Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1# SPDX-License-Identifier: GPL-2.0-only
2menu "Kernel hacking"
3
4menu "printk and dmesg options"
5
6config PRINTK_TIME
7 bool "Show timing information on printks"
8 depends on PRINTK
9 help
10 Selecting this option causes time stamps of the printk()
11 messages to be added to the output of the syslog() system
12 call and at the console.
13
14 The timestamp is always recorded internally, and exported
15 to /dev/kmsg. This flag just specifies if the timestamp should
16 be included, not that the timestamp is recorded.
17
18 The behavior is also controlled by the kernel command line
19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
20
21config PRINTK_CALLER
22 bool "Show caller information on printks"
23 depends on PRINTK
24 help
25 Selecting this option causes printk() to add a caller "thread id" (if
26 in task context) or a caller "processor id" (if not in task context)
27 to every message.
28
29 This option is intended for environments where multiple threads
30 concurrently call printk() for many times, for it is difficult to
31 interpret without knowing where these lines (or sometimes individual
32 line which was divided into multiple lines due to race) came from.
33
34 Since toggling after boot makes the code racy, currently there is
35 no option to enable/disable at the kernel command line parameter or
36 sysfs interface.
37
38config STACKTRACE_BUILD_ID
39 bool "Show build ID information in stacktraces"
40 depends on PRINTK
41 help
42 Selecting this option adds build ID information for symbols in
43 stacktraces printed with the printk format '%p[SR]b'.
44
45 This option is intended for distros where debuginfo is not easily
46 accessible but can be downloaded given the build ID of the vmlinux or
47 kernel module where the function is located.
48
49config CONSOLE_LOGLEVEL_DEFAULT
50 int "Default console loglevel (1-15)"
51 range 1 15
52 default "7"
53 help
54 Default loglevel to determine what will be printed on the console.
55
56 Setting a default here is equivalent to passing in loglevel=<x> in
57 the kernel bootargs. loglevel=<x> continues to override whatever
58 value is specified here as well.
59
60 Note: This does not affect the log level of un-prefixed printk()
61 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
62 option.
63
64config CONSOLE_LOGLEVEL_QUIET
65 int "quiet console loglevel (1-15)"
66 range 1 15
67 default "4"
68 help
69 loglevel to use when "quiet" is passed on the kernel commandline.
70
71 When "quiet" is passed on the kernel commandline this loglevel
72 will be used as the loglevel. IOW passing "quiet" will be the
73 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
74
75config MESSAGE_LOGLEVEL_DEFAULT
76 int "Default message log level (1-7)"
77 range 1 7
78 default "4"
79 help
80 Default log level for printk statements with no specified priority.
81
82 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83 that are auditing their logs closely may want to set it to a lower
84 priority.
85
86 Note: This does not affect what message level gets printed on the console
87 by default. To change that, use loglevel=<x> in the kernel bootargs,
88 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
89
90config BOOT_PRINTK_DELAY
91 bool "Delay each boot printk message by N milliseconds"
92 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
93 help
94 This build option allows you to read kernel boot messages
95 by inserting a short delay after each one. The delay is
96 specified in milliseconds on the kernel command line,
97 using "boot_delay=N".
98
99 It is likely that you would also need to use "lpj=M" to preset
100 the "loops per jiffy" value.
101 See a previous boot log for the "lpj" value to use for your
102 system, and then set "lpj=M" before setting "boot_delay=N".
103 NOTE: Using this option may adversely affect SMP systems.
104 I.e., processors other than the first one may not boot up.
105 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106 what it believes to be lockup conditions.
107
108config DYNAMIC_DEBUG
109 bool "Enable dynamic printk() support"
110 default n
111 depends on PRINTK
112 depends on (DEBUG_FS || PROC_FS)
113 select DYNAMIC_DEBUG_CORE
114 help
115
116 Compiles debug level messages into the kernel, which would not
117 otherwise be available at runtime. These messages can then be
118 enabled/disabled based on various levels of scope - per source file,
119 function, module, format string, and line number. This mechanism
120 implicitly compiles in all pr_debug() and dev_dbg() calls, which
121 enlarges the kernel text size by about 2%.
122
123 If a source file is compiled with DEBUG flag set, any
124 pr_debug() calls in it are enabled by default, but can be
125 disabled at runtime as below. Note that DEBUG flag is
126 turned on by many CONFIG_*DEBUG* options.
127
128 Usage:
129
130 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
131 which is contained in the 'debugfs' filesystem or procfs.
132 Thus, the debugfs or procfs filesystem must first be mounted before
133 making use of this feature.
134 We refer the control file as: <debugfs>/dynamic_debug/control. This
135 file contains a list of the debug statements that can be enabled. The
136 format for each line of the file is:
137
138 filename:lineno [module]function flags format
139
140 filename : source file of the debug statement
141 lineno : line number of the debug statement
142 module : module that contains the debug statement
143 function : function that contains the debug statement
144 flags : '=p' means the line is turned 'on' for printing
145 format : the format used for the debug statement
146
147 From a live system:
148
149 nullarbor:~ # cat <debugfs>/dynamic_debug/control
150 # filename:lineno [module]function flags format
151 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154
155 Example usage:
156
157 // enable the message at line 1603 of file svcsock.c
158 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159 <debugfs>/dynamic_debug/control
160
161 // enable all the messages in file svcsock.c
162 nullarbor:~ # echo -n 'file svcsock.c +p' >
163 <debugfs>/dynamic_debug/control
164
165 // enable all the messages in the NFS server module
166 nullarbor:~ # echo -n 'module nfsd +p' >
167 <debugfs>/dynamic_debug/control
168
169 // enable all 12 messages in the function svc_process()
170 nullarbor:~ # echo -n 'func svc_process +p' >
171 <debugfs>/dynamic_debug/control
172
173 // disable all 12 messages in the function svc_process()
174 nullarbor:~ # echo -n 'func svc_process -p' >
175 <debugfs>/dynamic_debug/control
176
177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
178 information.
179
180config DYNAMIC_DEBUG_CORE
181 bool "Enable core function of dynamic debug support"
182 depends on PRINTK
183 depends on (DEBUG_FS || PROC_FS)
184 help
185 Enable core functional support of dynamic debug. It is useful
186 when you want to tie dynamic debug to your kernel modules with
187 DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188 the case of embedded system where the kernel image size is
189 sensitive for people.
190
191config SYMBOLIC_ERRNAME
192 bool "Support symbolic error names in printf"
193 default y if PRINTK
194 help
195 If you say Y here, the kernel's printf implementation will
196 be able to print symbolic error names such as ENOSPC instead
197 of the number 28. It makes the kernel image slightly larger
198 (about 3KB), but can make the kernel logs easier to read.
199
200config DEBUG_BUGVERBOSE
201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
203 default y
204 help
205 Say Y here to make BUG() panics output the file name and line number
206 of the BUG call as well as the EIP and oops trace. This aids
207 debugging but costs about 70-100K of memory.
208
209config DEBUG_BUGVERBOSE_DETAILED
210 bool "Verbose WARN_ON_ONCE() reporting (adds 100K)" if DEBUG_BUGVERBOSE
211 help
212 Say Y here to make WARN_ON_ONCE() output the condition string of the
213 warning, in addition to the file name and line number.
214 This helps debugging, but costs about 100K of memory.
215
216 Say N if unsure.
217
218
219endmenu # "printk and dmesg options"
220
221config DEBUG_KERNEL
222 bool "Kernel debugging"
223 help
224 Say Y here if you are developing drivers or trying to debug and
225 identify kernel problems.
226
227config DEBUG_MISC
228 bool "Miscellaneous debug code"
229 default DEBUG_KERNEL
230 depends on DEBUG_KERNEL
231 help
232 Say Y here if you need to enable miscellaneous debug code that should
233 be under a more specific debug option but isn't.
234
235menu "Compile-time checks and compiler options"
236
237config DEBUG_INFO
238 bool
239 help
240 A kernel debug info option other than "None" has been selected
241 in the "Debug information" choice below, indicating that debug
242 information will be generated for build targets.
243
244# Clang generates .uleb128 with label differences for DWARF v5, a feature that
245# older binutils ports do not support when utilizing RISC-V style linker
246# relaxation: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
247config AS_HAS_NON_CONST_ULEB128
248 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
249
250choice
251 prompt "Debug information"
252 depends on DEBUG_KERNEL
253 help
254 Selecting something other than "None" results in a kernel image
255 that will include debugging info resulting in a larger kernel image.
256 This adds debug symbols to the kernel and modules (gcc -g), and
257 is needed if you intend to use kernel crashdump or binary object
258 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
259
260 Choose which version of DWARF debug info to emit. If unsure,
261 select "Toolchain default".
262
263config DEBUG_INFO_NONE
264 bool "Disable debug information"
265 help
266 Do not build the kernel with debugging information, which will
267 result in a faster and smaller build.
268
269config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
270 bool "Rely on the toolchain's implicit default DWARF version"
271 select DEBUG_INFO
272 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
273 help
274 The implicit default version of DWARF debug info produced by a
275 toolchain changes over time.
276
277 This can break consumers of the debug info that haven't upgraded to
278 support newer revisions, and prevent testing newer versions, but
279 those should be less common scenarios.
280
281config DEBUG_INFO_DWARF4
282 bool "Generate DWARF Version 4 debuginfo"
283 select DEBUG_INFO
284 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
285 help
286 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
287 if using clang without clang's integrated assembler, and gdb 7.0+.
288
289 If you have consumers of DWARF debug info that are not ready for
290 newer revisions of DWARF, you may wish to choose this or have your
291 config select this.
292
293config DEBUG_INFO_DWARF5
294 bool "Generate DWARF Version 5 debuginfo"
295 select DEBUG_INFO
296 depends on !ARCH_HAS_BROKEN_DWARF5
297 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
298 help
299 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
300 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
301 draft features until 7.0), and gdb 8.0+.
302
303 Changes to the structure of debug info in Version 5 allow for around
304 15-18% savings in resulting image and debug info section sizes as
305 compared to DWARF Version 4. DWARF Version 5 standardizes previous
306 extensions such as accelerators for symbol indexing and the format
307 for fission (.dwo/.dwp) files. Users may not want to select this
308 config if they rely on tooling that has not yet been updated to
309 support DWARF Version 5.
310
311endchoice # "Debug information"
312
313if DEBUG_INFO
314
315config DEBUG_INFO_REDUCED
316 bool "Reduce debugging information"
317 help
318 If you say Y here gcc is instructed to generate less debugging
319 information for structure types. This means that tools that
320 need full debugging information (like kgdb or systemtap) won't
321 be happy. But if you merely need debugging information to
322 resolve line numbers there is no loss. Advantage is that
323 build directory object sizes shrink dramatically over a full
324 DEBUG_INFO build and compile times are reduced too.
325 Only works with newer gcc versions.
326
327choice
328 prompt "Compressed Debug information"
329 help
330 Compress the resulting debug info. Results in smaller debug info sections,
331 but requires that consumers are able to decompress the results.
332
333 If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
334
335config DEBUG_INFO_COMPRESSED_NONE
336 bool "Don't compress debug information"
337 help
338 Don't compress debug info sections.
339
340config DEBUG_INFO_COMPRESSED_ZLIB
341 bool "Compress debugging information with zlib"
342 depends on $(cc-option,-gz=zlib)
343 depends on $(ld-option,--compress-debug-sections=zlib)
344 help
345 Compress the debug information using zlib.
346
347 Users of dpkg-deb via debian/rules may find an increase in
348 size of their debug .deb packages with this config set, due to the
349 debug info being compressed with zlib, then the object files being
350 recompressed with a different compression scheme. But this is still
351 preferable to setting KDEB_COMPRESS or DPKG_DEB_COMPRESSOR_TYPE to
352 "none" which would be even larger.
353
354config DEBUG_INFO_COMPRESSED_ZSTD
355 bool "Compress debugging information with zstd"
356 depends on $(cc-option,-gz=zstd)
357 depends on $(ld-option,--compress-debug-sections=zstd)
358 help
359 Compress the debug information using zstd. This may provide better
360 compression than zlib, for about the same time costs, but requires newer
361 toolchain support. Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
362 zstd.
363
364endchoice # "Compressed Debug information"
365
366config DEBUG_INFO_SPLIT
367 bool "Produce split debuginfo in .dwo files"
368 depends on $(cc-option,-gsplit-dwarf)
369 # RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC
370 # prior to 12.x:
371 # https://github.com/llvm/llvm-project/issues/56642
372 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090
373 depends on !RISCV || GCC_VERSION >= 120000
374 help
375 Generate debug info into separate .dwo files. This significantly
376 reduces the build directory size for builds with DEBUG_INFO,
377 because it stores the information only once on disk in .dwo
378 files instead of multiple times in object files and executables.
379 In addition the debug information is also compressed.
380
381 Requires recent gcc (4.7+) and recent gdb/binutils.
382 Any tool that packages or reads debug information would need
383 to know about the .dwo files and include them.
384 Incompatible with older versions of ccache.
385
386config DEBUG_INFO_BTF
387 bool "Generate BTF type information"
388 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
389 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
390 depends on BPF_SYSCALL
391 depends on PAHOLE_VERSION >= 116
392 depends on DEBUG_INFO_DWARF4 || PAHOLE_VERSION >= 121
393 # pahole uses elfutils, which does not have support for Hexagon relocations
394 depends on !HEXAGON
395 help
396 Generate deduplicated BTF type information from DWARF debug info.
397 Turning this on requires pahole v1.16 or later (v1.21 or later to
398 support DWARF 5), which will convert DWARF type info into equivalent
399 deduplicated BTF type info.
400
401config PAHOLE_HAS_SPLIT_BTF
402 def_bool PAHOLE_VERSION >= 119
403
404config PAHOLE_HAS_BTF_TAG
405 def_bool PAHOLE_VERSION >= 123
406 depends on CC_IS_CLANG
407 help
408 Decide whether pahole emits btf_tag attributes (btf_type_tag and
409 btf_decl_tag) or not. Currently only clang compiler implements
410 these attributes, so make the config depend on CC_IS_CLANG.
411
412config PAHOLE_HAS_LANG_EXCLUDE
413 def_bool PAHOLE_VERSION >= 124
414 help
415 Support for the --lang_exclude flag which makes pahole exclude
416 compilation units from the supplied language. Used in Kbuild to
417 omit Rust CUs which are not supported in version 1.24 of pahole,
418 otherwise it would emit malformed kernel and module binaries when
419 using DEBUG_INFO_BTF_MODULES.
420
421config DEBUG_INFO_BTF_MODULES
422 bool "Generate BTF type information for kernel modules"
423 default y
424 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
425 help
426 Generate compact split BTF type information for kernel modules.
427
428config MODULE_ALLOW_BTF_MISMATCH
429 bool "Allow loading modules with non-matching BTF type info"
430 depends on DEBUG_INFO_BTF_MODULES
431 help
432 For modules whose split BTF does not match vmlinux, load without
433 BTF rather than refusing to load. The default behavior with
434 module BTF enabled is to reject modules with such mismatches;
435 this option will still load module BTF where possible but ignore
436 it when a mismatch is found.
437
438config GDB_SCRIPTS
439 bool "Provide GDB scripts for kernel debugging"
440 help
441 This creates the required links to GDB helper scripts in the
442 build directory. If you load vmlinux into gdb, the helper
443 scripts will be automatically imported by gdb as well, and
444 additional functions are available to analyze a Linux kernel
445 instance. See Documentation/process/debugging/gdb-kernel-debugging.rst
446 for further details.
447
448endif # DEBUG_INFO
449
450config FRAME_WARN
451 int "Warn for stack frames larger than"
452 range 0 8192
453 default 0 if KMSAN
454 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
455 default 2048 if PARISC
456 default 1536 if (!64BIT && XTENSA)
457 default 1280 if !64BIT
458 default 2048 if 64BIT
459 help
460 Tell the compiler to warn at build time for stack frames larger than this.
461 Setting this too low will cause a lot of warnings.
462 Setting it to 0 disables the warning.
463
464config STRIP_ASM_SYMS
465 bool "Strip assembler-generated symbols during link"
466 default n
467 help
468 Strip internal assembler-generated symbols during a link (symbols
469 that look like '.Lxxx') so they don't pollute the output of
470 get_wchan() and suchlike.
471
472config READABLE_ASM
473 bool "Generate readable assembler code"
474 depends on DEBUG_KERNEL
475 depends on CC_IS_GCC
476 help
477 Disable some compiler optimizations that tend to generate human unreadable
478 assembler output. This may make the kernel slightly slower, but it helps
479 to keep kernel developers who have to stare a lot at assembler listings
480 sane.
481
482config HEADERS_INSTALL
483 bool "Install uapi headers to usr/include"
484 help
485 This option will install uapi headers (headers exported to user-space)
486 into the usr/include directory for use during the kernel build.
487 This is unneeded for building the kernel itself, but needed for some
488 user-space program samples. It is also needed by some features such
489 as uapi header sanity checks.
490
491config DEBUG_SECTION_MISMATCH
492 bool "Enable full Section mismatch analysis"
493 depends on CC_IS_GCC
494 help
495 The section mismatch analysis checks if there are illegal references
496 from one section to another. During linktime or runtime, some
497 sections are dropped; any use of code/data previously in these
498 sections would most likely result in an oops.
499
500 In the code, functions and variables are annotated with __init,
501 __initdata, and so on (see the full list in include/linux/init.h).
502 This directs the toolchain to place code/data in specific sections.
503
504 The section mismatch analysis is always performed after a full
505 kernel build, and enabling this option causes the option
506 -fno-inline-functions-called-once to be added to gcc commands.
507
508 However, when inlining a function annotated with __init in
509 a non-init function, we would lose the section information and thus
510 the analysis would not catch the illegal reference. This option
511 tells gcc to inline less (but it does result in a larger kernel).
512
513config SECTION_MISMATCH_WARN_ONLY
514 bool "Make section mismatch errors non-fatal"
515 default y
516 help
517 If you say N here, the build process will fail if there are any
518 section mismatch, instead of just throwing warnings.
519
520 If unsure, say Y.
521
522config DEBUG_FORCE_FUNCTION_ALIGN_64B
523 bool "Force all function address 64B aligned"
524 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390)
525 select FUNCTION_ALIGNMENT_64B
526 help
527 There are cases that a commit from one domain changes the function
528 address alignment of other domains, and cause magic performance
529 bump (regression or improvement). Enable this option will help to
530 verify if the bump is caused by function alignment changes, while
531 it will slightly increase the kernel size and affect icache usage.
532
533 It is mainly for debug and performance tuning use.
534
535#
536# Select this config option from the architecture Kconfig, if it
537# is preferred to always offer frame pointers as a config
538# option on the architecture (regardless of KERNEL_DEBUG):
539#
540config ARCH_WANT_FRAME_POINTERS
541 bool
542
543config FRAME_POINTER
544 bool "Compile the kernel with frame pointers"
545 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
546 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
547 help
548 If you say Y here the resulting kernel image will be slightly
549 larger and slower, but it gives very useful debugging information
550 in case of kernel bugs. (precise oopses/stacktraces/warnings)
551
552config OBJTOOL
553 bool
554
555config OBJTOOL_WERROR
556 bool "Upgrade objtool warnings to errors"
557 depends on OBJTOOL && !COMPILE_TEST
558 help
559 Fail the build on objtool warnings.
560
561 Objtool warnings can indicate kernel instability, including boot
562 failures. This option is highly recommended.
563
564 If unsure, say Y.
565
566config STACK_VALIDATION
567 bool "Compile-time stack metadata validation"
568 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
569 select OBJTOOL
570 default n
571 help
572 Validate frame pointer rules at compile-time. This helps ensure that
573 runtime stack traces are more reliable.
574
575 For more information, see
576 tools/objtool/Documentation/objtool.txt.
577
578config NOINSTR_VALIDATION
579 bool
580 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
581 select OBJTOOL
582 default y
583
584config VMLINUX_MAP
585 bool "Generate vmlinux.map file when linking"
586 depends on EXPERT
587 help
588 Selecting this option will pass "-Map=vmlinux.map" to ld
589 when linking vmlinux. That file can be useful for verifying
590 and debugging magic section games, and for seeing which
591 pieces of code get eliminated with
592 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
593
594config BUILTIN_MODULE_RANGES
595 bool "Generate address range information for builtin modules"
596 depends on !LTO
597 depends on VMLINUX_MAP
598 help
599 When modules are built into the kernel, there will be no module name
600 associated with its symbols in /proc/kallsyms. Tracers may want to
601 identify symbols by module name and symbol name regardless of whether
602 the module is configured as loadable or not.
603
604 This option generates modules.builtin.ranges in the build tree with
605 offset ranges (per ELF section) for the module(s) they belong to.
606 It also records an anchor symbol to determine the load address of the
607 section.
608
609config DEBUG_FORCE_WEAK_PER_CPU
610 bool "Force weak per-cpu definitions"
611 depends on DEBUG_KERNEL
612 help
613 s390 and alpha require percpu variables in modules to be
614 defined weak to work around addressing range issue which
615 puts the following two restrictions on percpu variable
616 definitions.
617
618 1. percpu symbols must be unique whether static or not
619 2. percpu variables can't be defined inside a function
620
621 To ensure that generic code follows the above rules, this
622 option forces all percpu variables to be defined as weak.
623
624endmenu # "Compiler options"
625
626menu "Generic Kernel Debugging Instruments"
627
628config MAGIC_SYSRQ
629 bool "Magic SysRq key"
630 depends on !UML
631 help
632 If you say Y here, you will have some control over the system even
633 if the system crashes for example during kernel debugging (e.g., you
634 will be able to flush the buffer cache to disk, reboot the system
635 immediately or dump some status information). This is accomplished
636 by pressing various keys while holding SysRq (Alt+PrintScreen). It
637 also works on a serial console (on PC hardware at least), if you
638 send a BREAK and then within 5 seconds a command keypress. The
639 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
640 Don't say Y unless you really know what this hack does.
641
642config MAGIC_SYSRQ_DEFAULT_ENABLE
643 hex "Enable magic SysRq key functions by default"
644 depends on MAGIC_SYSRQ
645 default 0x1
646 help
647 Specifies which SysRq key functions are enabled by default.
648 This may be set to 1 or 0 to enable or disable them all, or
649 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
650
651config MAGIC_SYSRQ_SERIAL
652 bool "Enable magic SysRq key over serial"
653 depends on MAGIC_SYSRQ
654 default y
655 help
656 Many embedded boards have a disconnected TTL level serial which can
657 generate some garbage that can lead to spurious false sysrq detects.
658 This option allows you to decide whether you want to enable the
659 magic SysRq key.
660
661config MAGIC_SYSRQ_SERIAL_SEQUENCE
662 string "Char sequence that enables magic SysRq over serial"
663 depends on MAGIC_SYSRQ_SERIAL
664 default ""
665 help
666 Specifies a sequence of characters that can follow BREAK to enable
667 SysRq on a serial console.
668
669 If unsure, leave an empty string and the option will not be enabled.
670
671config DEBUG_FS
672 bool "Debug Filesystem"
673 help
674 debugfs is a virtual file system that kernel developers use to put
675 debugging files into. Enable this option to be able to read and
676 write to these files.
677
678 For detailed documentation on the debugfs API, see
679 Documentation/filesystems/.
680
681 If unsure, say N.
682
683choice
684 prompt "Debugfs default access"
685 depends on DEBUG_FS
686 default DEBUG_FS_ALLOW_ALL
687 help
688 This selects the default access restrictions for debugfs.
689 It can be overridden with kernel command line option
690 debugfs=[on,off]. The restrictions apply for API access
691 and filesystem registration.
692
693config DEBUG_FS_ALLOW_ALL
694 bool "Access normal"
695 help
696 No restrictions apply. Both API and filesystem registration
697 is on. This is the normal default operation.
698
699config DEBUG_FS_ALLOW_NONE
700 bool "No access"
701 help
702 Access is off. Clients get -PERM when trying to create nodes in
703 debugfs tree and debugfs is not registered as a filesystem.
704 Client can then back-off or continue without debugfs access.
705
706endchoice
707
708source "lib/Kconfig.kgdb"
709source "lib/Kconfig.ubsan"
710source "lib/Kconfig.kcsan"
711
712endmenu
713
714menu "Networking Debugging"
715
716source "net/Kconfig.debug"
717
718endmenu # "Networking Debugging"
719
720menu "Memory Debugging"
721
722source "mm/Kconfig.debug"
723
724config DEBUG_OBJECTS
725 bool "Debug object operations"
726 depends on DEBUG_KERNEL
727 help
728 If you say Y here, additional code will be inserted into the
729 kernel to track the life time of various objects and validate
730 the operations on those objects.
731
732config DEBUG_OBJECTS_SELFTEST
733 bool "Debug objects selftest"
734 depends on DEBUG_OBJECTS
735 help
736 This enables the selftest of the object debug code.
737
738config DEBUG_OBJECTS_FREE
739 bool "Debug objects in freed memory"
740 depends on DEBUG_OBJECTS
741 help
742 This enables checks whether a k/v free operation frees an area
743 which contains an object which has not been deactivated
744 properly. This can make kmalloc/kfree-intensive workloads
745 much slower.
746
747config DEBUG_OBJECTS_TIMERS
748 bool "Debug timer objects"
749 depends on DEBUG_OBJECTS
750 help
751 If you say Y here, additional code will be inserted into the
752 timer routines to track the life time of timer objects and
753 validate the timer operations.
754
755config DEBUG_OBJECTS_WORK
756 bool "Debug work objects"
757 depends on DEBUG_OBJECTS
758 help
759 If you say Y here, additional code will be inserted into the
760 work queue routines to track the life time of work objects and
761 validate the work operations.
762
763config DEBUG_OBJECTS_RCU_HEAD
764 bool "Debug RCU callbacks objects"
765 depends on DEBUG_OBJECTS
766 help
767 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
768
769config DEBUG_OBJECTS_PERCPU_COUNTER
770 bool "Debug percpu counter objects"
771 depends on DEBUG_OBJECTS
772 help
773 If you say Y here, additional code will be inserted into the
774 percpu counter routines to track the life time of percpu counter
775 objects and validate the percpu counter operations.
776
777config DEBUG_OBJECTS_ENABLE_DEFAULT
778 int "debug_objects bootup default value (0-1)"
779 range 0 1
780 default "1"
781 depends on DEBUG_OBJECTS
782 help
783 Debug objects boot parameter default value
784
785config SHRINKER_DEBUG
786 bool "Enable shrinker debugging support"
787 depends on DEBUG_FS
788 help
789 Say Y to enable the shrinker debugfs interface which provides
790 visibility into the kernel memory shrinkers subsystem.
791 Disable it to avoid an extra memory footprint.
792
793config DEBUG_STACK_USAGE
794 bool "Stack utilization instrumentation"
795 depends on DEBUG_KERNEL
796 help
797 Enables the display of the minimum amount of free stack which each
798 task has ever had available in the sysrq-T and sysrq-P debug output.
799 Also emits a message to dmesg when a process exits if that process
800 used more stack space than previously exiting processes.
801
802 This option will slow down process creation somewhat.
803
804config SCHED_STACK_END_CHECK
805 bool "Detect stack corruption on calls to schedule()"
806 depends on DEBUG_KERNEL
807 default n
808 help
809 This option checks for a stack overrun on calls to schedule().
810 If the stack end location is found to be over written always panic as
811 the content of the corrupted region can no longer be trusted.
812 This is to ensure no erroneous behaviour occurs which could result in
813 data corruption or a sporadic crash at a later stage once the region
814 is examined. The runtime overhead introduced is minimal.
815
816config ARCH_HAS_DEBUG_VM_PGTABLE
817 bool
818 help
819 An architecture should select this when it can successfully
820 build and run DEBUG_VM_PGTABLE.
821
822config DEBUG_VFS
823 bool "Debug VFS"
824 depends on DEBUG_KERNEL
825 help
826 Enable this to turn on extended checks in the VFS layer that may impact
827 performance.
828
829 If unsure, say N.
830
831config DEBUG_VM_IRQSOFF
832 def_bool DEBUG_VM && !PREEMPT_RT
833
834config DEBUG_VM
835 bool "Debug VM"
836 depends on DEBUG_KERNEL
837 help
838 Enable this to turn on extended checks in the virtual-memory system
839 that may impact performance.
840
841 If unsure, say N.
842
843config DEBUG_VM_SHOOT_LAZIES
844 bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
845 depends on DEBUG_VM
846 depends on MMU_LAZY_TLB_SHOOTDOWN
847 help
848 Enable additional IPIs that ensure lazy tlb mm references are removed
849 before the mm is freed.
850
851 If unsure, say N.
852
853config DEBUG_VM_MAPLE_TREE
854 bool "Debug VM maple trees"
855 depends on DEBUG_VM
856 select DEBUG_MAPLE_TREE
857 help
858 Enable VM maple tree debugging information and extra validations.
859
860 If unsure, say N.
861
862config DEBUG_VM_RB
863 bool "Debug VM red-black trees"
864 depends on DEBUG_VM
865 help
866 Enable VM red-black tree debugging information and extra validations.
867
868 If unsure, say N.
869
870config DEBUG_VM_PGFLAGS
871 bool "Debug page-flags operations"
872 depends on DEBUG_VM
873 help
874 Enables extra validation on page flags operations.
875
876 If unsure, say N.
877
878config DEBUG_VM_PGTABLE
879 bool "Debug arch page table for semantics compliance"
880 depends on MMU
881 depends on ARCH_HAS_DEBUG_VM_PGTABLE
882 default y if DEBUG_VM
883 help
884 This option provides a debug method which can be used to test
885 architecture page table helper functions on various platforms in
886 verifying if they comply with expected generic MM semantics. This
887 will help architecture code in making sure that any changes or
888 new additions of these helpers still conform to expected
889 semantics of the generic MM. Platforms will have to opt in for
890 this through ARCH_HAS_DEBUG_VM_PGTABLE.
891
892 If unsure, say N.
893
894config ARCH_HAS_DEBUG_VIRTUAL
895 bool
896
897config DEBUG_VIRTUAL
898 bool "Debug VM translations"
899 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
900 help
901 Enable some costly sanity checks in virtual to page code. This can
902 catch mistakes with virt_to_page() and friends.
903
904 If unsure, say N.
905
906config DEBUG_NOMMU_REGIONS
907 bool "Debug the global anon/private NOMMU mapping region tree"
908 depends on DEBUG_KERNEL && !MMU
909 help
910 This option causes the global tree of anonymous and private mapping
911 regions to be regularly checked for invalid topology.
912
913config DEBUG_MEMORY_INIT
914 bool "Debug memory initialisation" if EXPERT
915 default !EXPERT
916 help
917 Enable this for additional checks during memory initialisation.
918 The sanity checks verify aspects of the VM such as the memory model
919 and other information provided by the architecture. Verbose
920 information will be printed at KERN_DEBUG loglevel depending
921 on the mminit_loglevel= command-line option.
922
923 If unsure, say Y
924
925config MEMORY_NOTIFIER_ERROR_INJECT
926 tristate "Memory hotplug notifier error injection module"
927 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
928 help
929 This option provides the ability to inject artificial errors to
930 memory hotplug notifier chain callbacks. It is controlled through
931 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
932
933 If the notifier call chain should be failed with some events
934 notified, write the error code to "actions/<notifier event>/error".
935
936 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
937
938 # cd /sys/kernel/debug/notifier-error-inject/memory
939 # echo -12 > actions/MEM_GOING_OFFLINE/error
940 # echo offline > /sys/devices/system/memory/memoryXXX/state
941 bash: echo: write error: Cannot allocate memory
942
943 To compile this code as a module, choose M here: the module will
944 be called memory-notifier-error-inject.
945
946 If unsure, say N.
947
948config DEBUG_PER_CPU_MAPS
949 bool "Debug access to per_cpu maps"
950 depends on DEBUG_KERNEL
951 depends on SMP
952 help
953 Say Y to verify that the per_cpu map being accessed has
954 been set up. This adds a fair amount of code to kernel memory
955 and decreases performance.
956
957 Say N if unsure.
958
959config DEBUG_KMAP_LOCAL
960 bool "Debug kmap_local temporary mappings"
961 depends on DEBUG_KERNEL && KMAP_LOCAL
962 help
963 This option enables additional error checking for the kmap_local
964 infrastructure. Disable for production use.
965
966config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
967 bool
968
969config DEBUG_KMAP_LOCAL_FORCE_MAP
970 bool "Enforce kmap_local temporary mappings"
971 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
972 select KMAP_LOCAL
973 select DEBUG_KMAP_LOCAL
974 help
975 This option enforces temporary mappings through the kmap_local
976 mechanism for non-highmem pages and on non-highmem systems.
977 Disable this for production systems!
978
979config DEBUG_HIGHMEM
980 bool "Highmem debugging"
981 depends on DEBUG_KERNEL && HIGHMEM
982 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
983 select DEBUG_KMAP_LOCAL
984 help
985 This option enables additional error checking for high memory
986 systems. Disable for production systems.
987
988config HAVE_DEBUG_STACKOVERFLOW
989 bool
990
991config DEBUG_STACKOVERFLOW
992 bool "Check for stack overflows"
993 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
994 help
995 Say Y here if you want to check for overflows of kernel, IRQ
996 and exception stacks (if your architecture uses them). This
997 option will show detailed messages if free stack space drops
998 below a certain limit.
999
1000 These kinds of bugs usually occur when call-chains in the
1001 kernel get too deep, especially when interrupts are
1002 involved.
1003
1004 Use this in cases where you see apparently random memory
1005 corruption, especially if it appears in 'struct thread_info'
1006
1007 If in doubt, say "N".
1008
1009config CODE_TAGGING
1010 bool
1011 select KALLSYMS
1012
1013config MEM_ALLOC_PROFILING
1014 bool "Enable memory allocation profiling"
1015 default n
1016 depends on MMU
1017 depends on PROC_FS
1018 depends on !DEBUG_FORCE_WEAK_PER_CPU
1019 select CODE_TAGGING
1020 select PAGE_EXTENSION
1021 select SLAB_OBJ_EXT
1022 help
1023 Track allocation source code and record total allocation size
1024 initiated at that code location. The mechanism can be used to track
1025 memory leaks with a low performance and memory impact.
1026
1027config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1028 bool "Enable memory allocation profiling by default"
1029 default y
1030 depends on MEM_ALLOC_PROFILING
1031
1032config MEM_ALLOC_PROFILING_DEBUG
1033 bool "Memory allocation profiler debugging"
1034 default n
1035 depends on MEM_ALLOC_PROFILING
1036 select MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1037 help
1038 Adds warnings with helpful error messages for memory allocation
1039 profiling.
1040
1041source "lib/Kconfig.kasan"
1042source "lib/Kconfig.kfence"
1043source "lib/Kconfig.kmsan"
1044
1045endmenu # "Memory Debugging"
1046
1047config DEBUG_SHIRQ
1048 bool "Debug shared IRQ handlers"
1049 depends on DEBUG_KERNEL
1050 help
1051 Enable this to generate a spurious interrupt just before a shared
1052 interrupt handler is deregistered (generating one when registering
1053 is currently disabled). Drivers need to handle this correctly. Some
1054 don't and need to be caught.
1055
1056menu "Debug Oops, Lockups and Hangs"
1057
1058config PANIC_ON_OOPS
1059 bool "Panic on Oops"
1060 help
1061 Say Y here to enable the kernel to panic when it oopses. This
1062 has the same effect as setting oops=panic on the kernel command
1063 line.
1064
1065 This feature is useful to ensure that the kernel does not do
1066 anything erroneous after an oops which could result in data
1067 corruption or other issues.
1068
1069 Say N if unsure.
1070
1071config PANIC_TIMEOUT
1072 int "panic timeout"
1073 default 0
1074 help
1075 Set the timeout value (in seconds) until a reboot occurs when
1076 the kernel panics. If n = 0, then we wait forever. A timeout
1077 value n > 0 will wait n seconds before rebooting, while a timeout
1078 value n < 0 will reboot immediately. This setting can be overridden
1079 with the kernel command line option panic=, and from userspace via
1080 /proc/sys/kernel/panic.
1081
1082config LOCKUP_DETECTOR
1083 bool
1084
1085config SOFTLOCKUP_DETECTOR
1086 bool "Detect Soft Lockups"
1087 depends on DEBUG_KERNEL && !S390
1088 select LOCKUP_DETECTOR
1089 help
1090 Say Y here to enable the kernel to act as a watchdog to detect
1091 soft lockups.
1092
1093 Softlockups are bugs that cause the kernel to loop in kernel
1094 mode for more than 20 seconds, without giving other tasks a
1095 chance to run. The current stack trace is displayed upon
1096 detection and the system will stay locked up.
1097
1098config SOFTLOCKUP_DETECTOR_INTR_STORM
1099 bool "Detect Interrupt Storm in Soft Lockups"
1100 depends on SOFTLOCKUP_DETECTOR && IRQ_TIME_ACCOUNTING
1101 select GENERIC_IRQ_STAT_SNAPSHOT
1102 default y if NR_CPUS <= 128
1103 help
1104 Say Y here to enable the kernel to detect interrupt storm
1105 during "soft lockups".
1106
1107 "soft lockups" can be caused by a variety of reasons. If one is
1108 caused by an interrupt storm, then the storming interrupts will not
1109 be on the callstack. To detect this case, it is necessary to report
1110 the CPU stats and the interrupt counts during the "soft lockups".
1111
1112config BOOTPARAM_SOFTLOCKUP_PANIC
1113 bool "Panic (Reboot) On Soft Lockups"
1114 depends on SOFTLOCKUP_DETECTOR
1115 help
1116 Say Y here to enable the kernel to panic on "soft lockups",
1117 which are bugs that cause the kernel to loop in kernel
1118 mode for more than 20 seconds (configurable using the watchdog_thresh
1119 sysctl), without giving other tasks a chance to run.
1120
1121 The panic can be used in combination with panic_timeout,
1122 to cause the system to reboot automatically after a
1123 lockup has been detected. This feature is useful for
1124 high-availability systems that have uptime guarantees and
1125 where a lockup must be resolved ASAP.
1126
1127 Say N if unsure.
1128
1129config HAVE_HARDLOCKUP_DETECTOR_BUDDY
1130 bool
1131 depends on SMP
1132 default y
1133
1134#
1135# Global switch whether to build a hardlockup detector at all. It is available
1136# only when the architecture supports at least one implementation. There are
1137# two exceptions. The hardlockup detector is never enabled on:
1138#
1139# s390: it reported many false positives there
1140#
1141# sparc64: has a custom implementation which is not using the common
1142# hardlockup command line options and sysctl interface.
1143#
1144config HARDLOCKUP_DETECTOR
1145 bool "Detect Hard Lockups"
1146 depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
1147 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
1148 imply HARDLOCKUP_DETECTOR_PERF
1149 imply HARDLOCKUP_DETECTOR_BUDDY
1150 imply HARDLOCKUP_DETECTOR_ARCH
1151 select LOCKUP_DETECTOR
1152
1153 help
1154 Say Y here to enable the kernel to act as a watchdog to detect
1155 hard lockups.
1156
1157 Hardlockups are bugs that cause the CPU to loop in kernel mode
1158 for more than 10 seconds, without letting other interrupts have a
1159 chance to run. The current stack trace is displayed upon detection
1160 and the system will stay locked up.
1161
1162#
1163# Note that arch-specific variants are always preferred.
1164#
1165config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1166 bool "Prefer the buddy CPU hardlockup detector"
1167 depends on HARDLOCKUP_DETECTOR
1168 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
1169 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1170 help
1171 Say Y here to prefer the buddy hardlockup detector over the perf one.
1172
1173 With the buddy detector, each CPU uses its softlockup hrtimer
1174 to check that the next CPU is processing hrtimer interrupts by
1175 verifying that a counter is increasing.
1176
1177 This hardlockup detector is useful on systems that don't have
1178 an arch-specific hardlockup detector or if resources needed
1179 for the hardlockup detector are better used for other things.
1180
1181config HARDLOCKUP_DETECTOR_PERF
1182 bool
1183 depends on HARDLOCKUP_DETECTOR
1184 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
1185 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1186 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1187
1188config HARDLOCKUP_DETECTOR_BUDDY
1189 bool
1190 depends on HARDLOCKUP_DETECTOR
1191 depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1192 depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
1193 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1194 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1195
1196config HARDLOCKUP_DETECTOR_ARCH
1197 bool
1198 depends on HARDLOCKUP_DETECTOR
1199 depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1200 help
1201 The arch-specific implementation of the hardlockup detector will
1202 be used.
1203
1204#
1205# Both the "perf" and "buddy" hardlockup detectors count hrtimer
1206# interrupts. This config enables functions managing this common code.
1207#
1208config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1209 bool
1210 select SOFTLOCKUP_DETECTOR
1211
1212#
1213# Enables a timestamp based low pass filter to compensate for perf based
1214# hard lockup detection which runs too fast due to turbo modes.
1215#
1216config HARDLOCKUP_CHECK_TIMESTAMP
1217 bool
1218
1219config BOOTPARAM_HARDLOCKUP_PANIC
1220 bool "Panic (Reboot) On Hard Lockups"
1221 depends on HARDLOCKUP_DETECTOR
1222 help
1223 Say Y here to enable the kernel to panic on "hard lockups",
1224 which are bugs that cause the kernel to loop in kernel
1225 mode with interrupts disabled for more than 10 seconds (configurable
1226 using the watchdog_thresh sysctl).
1227
1228 Say N if unsure.
1229
1230config DETECT_HUNG_TASK
1231 bool "Detect Hung Tasks"
1232 depends on DEBUG_KERNEL
1233 default SOFTLOCKUP_DETECTOR
1234 help
1235 Say Y here to enable the kernel to detect "hung tasks",
1236 which are bugs that cause the task to be stuck in
1237 uninterruptible "D" state indefinitely.
1238
1239 When a hung task is detected, the kernel will print the
1240 current stack trace (which you should report), but the
1241 task will stay in uninterruptible state. If lockdep is
1242 enabled then all held locks will also be reported. This
1243 feature has negligible overhead.
1244
1245config DEFAULT_HUNG_TASK_TIMEOUT
1246 int "Default timeout for hung task detection (in seconds)"
1247 depends on DETECT_HUNG_TASK
1248 default 120
1249 help
1250 This option controls the default timeout (in seconds) used
1251 to determine when a task has become non-responsive and should
1252 be considered hung.
1253
1254 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1255 sysctl or by writing a value to
1256 /proc/sys/kernel/hung_task_timeout_secs.
1257
1258 A timeout of 0 disables the check. The default is two minutes.
1259 Keeping the default should be fine in most cases.
1260
1261config BOOTPARAM_HUNG_TASK_PANIC
1262 int "Number of hung tasks to trigger kernel panic"
1263 depends on DETECT_HUNG_TASK
1264 default 0
1265 help
1266 When set to a non-zero value, a kernel panic will be triggered
1267 if the number of hung tasks found during a single scan reaches
1268 this value.
1269
1270 The panic can be used in combination with panic_timeout,
1271 to cause the system to reboot automatically after a
1272 hung task has been detected. This feature is useful for
1273 high-availability systems that have uptime guarantees and
1274 where a hung tasks must be resolved ASAP.
1275
1276 Say N if unsure.
1277
1278config DETECT_HUNG_TASK_BLOCKER
1279 bool "Dump Hung Tasks Blocker"
1280 depends on DETECT_HUNG_TASK
1281 depends on !PREEMPT_RT
1282 default y
1283 help
1284 Say Y here to show the blocker task's stacktrace who acquires
1285 the mutex lock which "hung tasks" are waiting.
1286 This will add overhead a bit but shows suspicious tasks and
1287 call trace if it comes from waiting a mutex.
1288
1289config WQ_WATCHDOG
1290 bool "Detect Workqueue Stalls"
1291 depends on DEBUG_KERNEL
1292 help
1293 Say Y here to enable stall detection on workqueues. If a
1294 worker pool doesn't make forward progress on a pending work
1295 item for over a given amount of time, 30s by default, a
1296 warning message is printed along with dump of workqueue
1297 state. This can be configured through kernel parameter
1298 "workqueue.watchdog_thresh" and its sysfs counterpart.
1299
1300config WQ_CPU_INTENSIVE_REPORT
1301 bool "Report per-cpu work items which hog CPU for too long"
1302 depends on DEBUG_KERNEL
1303 help
1304 Say Y here to enable reporting of concurrency-managed per-cpu work
1305 items that hog CPUs for longer than
1306 workqueue.cpu_intensive_thresh_us. Workqueue automatically
1307 detects and excludes them from concurrency management to prevent
1308 them from stalling other per-cpu work items. Occassional
1309 triggering may not necessarily indicate a problem. Repeated
1310 triggering likely indicates that the work item should be switched
1311 to use an unbound workqueue.
1312
1313config TEST_LOCKUP
1314 tristate "Test module to generate lockups"
1315 depends on m
1316 help
1317 This builds the "test_lockup" module that helps to make sure
1318 that watchdogs and lockup detectors are working properly.
1319
1320 Depending on module parameters it could emulate soft or hard
1321 lockup, "hung task", or locking arbitrary lock for a long time.
1322 Also it could generate series of lockups with cooling-down periods.
1323
1324 If unsure, say N.
1325
1326endmenu # "Debug lockups and hangs"
1327
1328menu "Scheduler Debugging"
1329
1330config SCHED_INFO
1331 bool
1332 default n
1333
1334config SCHEDSTATS
1335 bool "Collect scheduler statistics"
1336 depends on PROC_FS
1337 select SCHED_INFO
1338 help
1339 If you say Y here, additional code will be inserted into the
1340 scheduler and related routines to collect statistics about
1341 scheduler behavior and provide them in /proc/schedstat. These
1342 stats may be useful for both tuning and debugging the scheduler
1343 If you aren't debugging the scheduler or trying to tune a specific
1344 application, you can say N to avoid the very slight overhead
1345 this adds.
1346
1347endmenu
1348
1349config DEBUG_PREEMPT
1350 bool "Debug preemptible kernel"
1351 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1352 help
1353 If you say Y here then the kernel will use a debug variant of the
1354 commonly used smp_processor_id() function and will print warnings
1355 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1356 will detect preemption count underflows.
1357
1358 This option has potential to introduce high runtime overhead,
1359 depending on workload as it triggers debugging routines for each
1360 this_cpu operation. It should only be used for debugging purposes.
1361
1362menu "Lock Debugging (spinlocks, mutexes, etc...)"
1363
1364config LOCK_DEBUGGING_SUPPORT
1365 bool
1366 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1367 default y
1368
1369config PROVE_LOCKING
1370 bool "Lock debugging: prove locking correctness"
1371 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1372 select LOCKDEP
1373 select DEBUG_SPINLOCK
1374 select DEBUG_MUTEXES if !PREEMPT_RT
1375 select DEBUG_RT_MUTEXES if RT_MUTEXES
1376 select DEBUG_RWSEMS if !PREEMPT_RT
1377 select DEBUG_WW_MUTEX_SLOWPATH
1378 select DEBUG_LOCK_ALLOC
1379 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1380 select TRACE_IRQFLAGS
1381 default n
1382 help
1383 This feature enables the kernel to prove that all locking
1384 that occurs in the kernel runtime is mathematically
1385 correct: that under no circumstance could an arbitrary (and
1386 not yet triggered) combination of observed locking
1387 sequences (on an arbitrary number of CPUs, running an
1388 arbitrary number of tasks and interrupt contexts) cause a
1389 deadlock.
1390
1391 In short, this feature enables the kernel to report locking
1392 related deadlocks before they actually occur.
1393
1394 The proof does not depend on how hard and complex a
1395 deadlock scenario would be to trigger: how many
1396 participant CPUs, tasks and irq-contexts would be needed
1397 for it to trigger. The proof also does not depend on
1398 timing: if a race and a resulting deadlock is possible
1399 theoretically (no matter how unlikely the race scenario
1400 is), it will be proven so and will immediately be
1401 reported by the kernel (once the event is observed that
1402 makes the deadlock theoretically possible).
1403
1404 If a deadlock is impossible (i.e. the locking rules, as
1405 observed by the kernel, are mathematically correct), the
1406 kernel reports nothing.
1407
1408 NOTE: this feature can also be enabled for rwlocks, mutexes
1409 and rwsems - in which case all dependencies between these
1410 different locking variants are observed and mapped too, and
1411 the proof of observed correctness is also maintained for an
1412 arbitrary combination of these separate locking variants.
1413
1414 For more details, see Documentation/locking/lockdep-design.rst.
1415
1416config PROVE_RAW_LOCK_NESTING
1417 bool "Enable raw_spinlock - spinlock nesting checks" if !ARCH_SUPPORTS_RT
1418 depends on PROVE_LOCKING
1419 default y if ARCH_SUPPORTS_RT
1420 help
1421 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1422 that the lock nesting rules for PREEMPT_RT enabled kernels are
1423 not violated.
1424
1425config LOCK_STAT
1426 bool "Lock usage statistics"
1427 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1428 select LOCKDEP
1429 select DEBUG_SPINLOCK
1430 select DEBUG_MUTEXES if !PREEMPT_RT
1431 select DEBUG_RT_MUTEXES if RT_MUTEXES
1432 select DEBUG_LOCK_ALLOC
1433 default n
1434 help
1435 This feature enables tracking lock contention points
1436
1437 For more details, see Documentation/locking/lockstat.rst
1438
1439 This also enables lock events required by "perf lock",
1440 subcommand of perf.
1441 If you want to use "perf lock", you also need to turn on
1442 CONFIG_EVENT_TRACING.
1443
1444 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1445 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1446
1447config DEBUG_RT_MUTEXES
1448 bool "RT Mutex debugging, deadlock detection"
1449 depends on DEBUG_KERNEL && RT_MUTEXES
1450 help
1451 This allows rt mutex semantics violations and rt mutex related
1452 deadlocks (lockups) to be detected and reported automatically.
1453
1454config DEBUG_SPINLOCK
1455 bool "Spinlock and rw-lock debugging: basic checks"
1456 depends on DEBUG_KERNEL
1457 select UNINLINE_SPIN_UNLOCK
1458 help
1459 Say Y here and build SMP to catch missing spinlock initialization
1460 and certain other kinds of spinlock errors commonly made. This is
1461 best used in conjunction with the NMI watchdog so that spinlock
1462 deadlocks are also debuggable.
1463
1464config DEBUG_MUTEXES
1465 bool "Mutex debugging: basic checks"
1466 depends on DEBUG_KERNEL && !PREEMPT_RT
1467 help
1468 This feature allows mutex semantics violations to be detected and
1469 reported.
1470
1471config DEBUG_WW_MUTEX_SLOWPATH
1472 bool "Wait/wound mutex debugging: Slowpath testing"
1473 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1474 select DEBUG_LOCK_ALLOC
1475 select DEBUG_SPINLOCK
1476 select DEBUG_MUTEXES if !PREEMPT_RT
1477 select DEBUG_RT_MUTEXES if PREEMPT_RT
1478 help
1479 This feature enables slowpath testing for w/w mutex users by
1480 injecting additional -EDEADLK wound/backoff cases. Together with
1481 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1482 will test all possible w/w mutex interface abuse with the
1483 exception of simply not acquiring all the required locks.
1484 Note that this feature can introduce significant overhead, so
1485 it really should not be enabled in a production or distro kernel,
1486 even a debug kernel. If you are a driver writer, enable it. If
1487 you are a distro, do not.
1488
1489config DEBUG_RWSEMS
1490 bool "RW Semaphore debugging: basic checks"
1491 depends on DEBUG_KERNEL && !PREEMPT_RT
1492 help
1493 This debugging feature allows mismatched rw semaphore locks
1494 and unlocks to be detected and reported.
1495
1496config DEBUG_LOCK_ALLOC
1497 bool "Lock debugging: detect incorrect freeing of live locks"
1498 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1499 select DEBUG_SPINLOCK
1500 select DEBUG_MUTEXES if !PREEMPT_RT
1501 select DEBUG_RT_MUTEXES if RT_MUTEXES
1502 select LOCKDEP
1503 help
1504 This feature will check whether any held lock (spinlock, rwlock,
1505 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1506 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1507 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1508 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1509 held during task exit.
1510
1511config LOCKDEP
1512 bool
1513 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1514 select STACKTRACE
1515 select KALLSYMS
1516 select KALLSYMS_ALL
1517
1518config LOCKDEP_SMALL
1519 bool
1520
1521config LOCKDEP_BITS
1522 int "Size for MAX_LOCKDEP_ENTRIES (as Nth power of 2)"
1523 depends on LOCKDEP && !LOCKDEP_SMALL
1524 range 10 24
1525 default 15
1526 help
1527 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1528
1529config LOCKDEP_CHAINS_BITS
1530 int "Size for MAX_LOCKDEP_CHAINS (as Nth power of 2)"
1531 depends on LOCKDEP && !LOCKDEP_SMALL
1532 range 10 21
1533 default 16
1534 help
1535 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1536
1537config LOCKDEP_STACK_TRACE_BITS
1538 int "Size for MAX_STACK_TRACE_ENTRIES (as Nth power of 2)"
1539 depends on LOCKDEP && !LOCKDEP_SMALL
1540 range 10 26
1541 default 19
1542 help
1543 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1544
1545config LOCKDEP_STACK_TRACE_HASH_BITS
1546 int "Size for STACK_TRACE_HASH_SIZE (as Nth power of 2)"
1547 depends on LOCKDEP && !LOCKDEP_SMALL
1548 range 10 26
1549 default 14
1550 help
1551 Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1552
1553config LOCKDEP_CIRCULAR_QUEUE_BITS
1554 int "Size for elements in circular_queue struct (as Nth power of 2)"
1555 depends on LOCKDEP
1556 range 10 26
1557 default 12
1558 help
1559 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1560
1561config DEBUG_LOCKDEP
1562 bool "Lock dependency engine debugging"
1563 depends on DEBUG_KERNEL && LOCKDEP
1564 select DEBUG_IRQFLAGS
1565 help
1566 If you say Y here, the lock dependency engine will do
1567 additional runtime checks to debug itself, at the price
1568 of more runtime overhead.
1569
1570config DEBUG_ATOMIC_SLEEP
1571 bool "Sleep inside atomic section checking"
1572 select PREEMPT_COUNT
1573 depends on DEBUG_KERNEL
1574 depends on !ARCH_NO_PREEMPT
1575 help
1576 If you say Y here, various routines which may sleep will become very
1577 noisy if they are called inside atomic sections: when a spinlock is
1578 held, inside an rcu read side critical section, inside preempt disabled
1579 sections, inside an interrupt, etc...
1580
1581config DEBUG_LOCKING_API_SELFTESTS
1582 bool "Locking API boot-time self-tests"
1583 depends on DEBUG_KERNEL
1584 help
1585 Say Y here if you want the kernel to run a short self-test during
1586 bootup. The self-test checks whether common types of locking bugs
1587 are detected by debugging mechanisms or not. (if you disable
1588 lock debugging then those bugs won't be detected of course.)
1589 The following locking APIs are covered: spinlocks, rwlocks,
1590 mutexes and rwsems.
1591
1592config LOCK_TORTURE_TEST
1593 tristate "torture tests for locking"
1594 depends on DEBUG_KERNEL
1595 select TORTURE_TEST
1596 help
1597 This option provides a kernel module that runs torture tests
1598 on kernel locking primitives. The kernel module may be built
1599 after the fact on the running kernel to be tested, if desired.
1600
1601 Say Y here if you want kernel locking-primitive torture tests
1602 to be built into the kernel.
1603 Say M if you want these torture tests to build as a module.
1604 Say N if you are unsure.
1605
1606config WW_MUTEX_SELFTEST
1607 tristate "Wait/wound mutex selftests"
1608 help
1609 This option provides a kernel module that runs tests on the
1610 on the struct ww_mutex locking API.
1611
1612 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1613 with this test harness.
1614
1615 Say M if you want these self tests to build as a module.
1616 Say N if you are unsure.
1617
1618config SCF_TORTURE_TEST
1619 tristate "torture tests for smp_call_function*()"
1620 depends on DEBUG_KERNEL
1621 select TORTURE_TEST
1622 help
1623 This option provides a kernel module that runs torture tests
1624 on the smp_call_function() family of primitives. The kernel
1625 module may be built after the fact on the running kernel to
1626 be tested, if desired.
1627
1628config CSD_LOCK_WAIT_DEBUG
1629 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1630 depends on DEBUG_KERNEL
1631 depends on SMP
1632 depends on 64BIT
1633 default n
1634 help
1635 This option enables debug prints when CPUs are slow to respond
1636 to the smp_call_function*() IPI wrappers. These debug prints
1637 include the IPI handler function currently executing (if any)
1638 and relevant stack traces.
1639
1640config CSD_LOCK_WAIT_DEBUG_DEFAULT
1641 bool "Default csd_lock_wait() debugging on at boot time"
1642 depends on CSD_LOCK_WAIT_DEBUG
1643 depends on 64BIT
1644 default n
1645 help
1646 This option causes the csdlock_debug= kernel boot parameter to
1647 default to 1 (basic debugging) instead of 0 (no debugging).
1648
1649endmenu # lock debugging
1650
1651config TRACE_IRQFLAGS
1652 depends on TRACE_IRQFLAGS_SUPPORT
1653 bool
1654 help
1655 Enables hooks to interrupt enabling and disabling for
1656 either tracing or lock debugging.
1657
1658config TRACE_IRQFLAGS_NMI
1659 def_bool y
1660 depends on TRACE_IRQFLAGS
1661 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1662
1663config NMI_CHECK_CPU
1664 bool "Debugging for CPUs failing to respond to backtrace requests"
1665 depends on DEBUG_KERNEL
1666 depends on X86
1667 default n
1668 help
1669 Enables debug prints when a CPU fails to respond to a given
1670 backtrace NMI. These prints provide some reasons why a CPU
1671 might legitimately be failing to respond, for example, if it
1672 is offline of if ignore_nmis is set.
1673
1674config DEBUG_IRQFLAGS
1675 bool "Debug IRQ flag manipulation"
1676 help
1677 Enables checks for potentially unsafe enabling or disabling of
1678 interrupts, such as calling raw_local_irq_restore() when interrupts
1679 are enabled.
1680
1681config STACKTRACE
1682 bool "Stack backtrace support"
1683 depends on STACKTRACE_SUPPORT
1684 help
1685 This option causes the kernel to create a /proc/pid/stack for
1686 every process, showing its current stack trace.
1687 It is also used by various kernel debugging features that require
1688 stack trace generation.
1689
1690config WARN_ALL_UNSEEDED_RANDOM
1691 bool "Warn for all uses of unseeded randomness"
1692 default n
1693 help
1694 Some parts of the kernel contain bugs relating to their use of
1695 cryptographically secure random numbers before it's actually possible
1696 to generate those numbers securely. This setting ensures that these
1697 flaws don't go unnoticed, by enabling a message, should this ever
1698 occur. This will allow people with obscure setups to know when things
1699 are going wrong, so that they might contact developers about fixing
1700 it.
1701
1702 Unfortunately, on some models of some architectures getting
1703 a fully seeded CRNG is extremely difficult, and so this can
1704 result in dmesg getting spammed for a surprisingly long
1705 time. This is really bad from a security perspective, and
1706 so architecture maintainers really need to do what they can
1707 to get the CRNG seeded sooner after the system is booted.
1708 However, since users cannot do anything actionable to
1709 address this, by default this option is disabled.
1710
1711 Say Y here if you want to receive warnings for all uses of
1712 unseeded randomness. This will be of use primarily for
1713 those developers interested in improving the security of
1714 Linux kernels running on their architecture (or
1715 subarchitecture).
1716
1717config DEBUG_KOBJECT
1718 bool "kobject debugging"
1719 depends on DEBUG_KERNEL
1720 help
1721 If you say Y here, some extra kobject debugging messages will be sent
1722 to the syslog.
1723
1724config DEBUG_KOBJECT_RELEASE
1725 bool "kobject release debugging"
1726 depends on DEBUG_OBJECTS_TIMERS
1727 help
1728 kobjects are reference counted objects. This means that their
1729 last reference count put is not predictable, and the kobject can
1730 live on past the point at which a driver decides to drop its
1731 initial reference to the kobject gained on allocation. An
1732 example of this would be a struct device which has just been
1733 unregistered.
1734
1735 However, some buggy drivers assume that after such an operation,
1736 the memory backing the kobject can be immediately freed. This
1737 goes completely against the principles of a refcounted object.
1738
1739 If you say Y here, the kernel will delay the release of kobjects
1740 on the last reference count to improve the visibility of this
1741 kind of kobject release bug.
1742
1743config HAVE_DEBUG_BUGVERBOSE
1744 bool
1745
1746menu "Debug kernel data structures"
1747
1748config DEBUG_LIST
1749 bool "Debug linked list manipulation"
1750 depends on DEBUG_KERNEL
1751 select LIST_HARDENED
1752 help
1753 Enable this to turn on extended checks in the linked-list walking
1754 routines.
1755
1756 This option trades better quality error reports for performance, and
1757 is more suitable for kernel debugging. If you care about performance,
1758 you should only enable CONFIG_LIST_HARDENED instead.
1759
1760 If unsure, say N.
1761
1762config DEBUG_PLIST
1763 bool "Debug priority linked list manipulation"
1764 depends on DEBUG_KERNEL
1765 help
1766 Enable this to turn on extended checks in the priority-ordered
1767 linked-list (plist) walking routines. This checks the entire
1768 list multiple times during each manipulation.
1769
1770 If unsure, say N.
1771
1772config DEBUG_SG
1773 bool "Debug SG table operations"
1774 depends on DEBUG_KERNEL
1775 help
1776 Enable this to turn on checks on scatter-gather tables. This can
1777 help find problems with drivers that do not properly initialize
1778 their sg tables.
1779
1780 If unsure, say N.
1781
1782config DEBUG_NOTIFIERS
1783 bool "Debug notifier call chains"
1784 depends on DEBUG_KERNEL
1785 help
1786 Enable this to turn on sanity checking for notifier call chains.
1787 This is most useful for kernel developers to make sure that
1788 modules properly unregister themselves from notifier chains.
1789 This is a relatively cheap check but if you care about maximum
1790 performance, say N.
1791
1792config DEBUG_CLOSURES
1793 bool "Debug closures (bcache async widgits)"
1794 depends on CLOSURES
1795 select DEBUG_FS
1796 help
1797 Keeps all active closures in a linked list and provides a debugfs
1798 interface to list them, which makes it possible to see asynchronous
1799 operations that get stuck.
1800
1801config DEBUG_MAPLE_TREE
1802 bool "Debug maple trees"
1803 depends on DEBUG_KERNEL
1804 help
1805 Enable maple tree debugging information and extra validations.
1806
1807 If unsure, say N.
1808
1809endmenu
1810
1811source "kernel/rcu/Kconfig.debug"
1812
1813config DEBUG_WQ_FORCE_RR_CPU
1814 bool "Force round-robin CPU selection for unbound work items"
1815 depends on DEBUG_KERNEL
1816 default n
1817 help
1818 Workqueue used to implicitly guarantee that work items queued
1819 without explicit CPU specified are put on the local CPU. This
1820 guarantee is no longer true and while local CPU is still
1821 preferred work items may be put on foreign CPUs. Kernel
1822 parameter "workqueue.debug_force_rr_cpu" is added to force
1823 round-robin CPU selection to flush out usages which depend on the
1824 now broken guarantee. This config option enables the debug
1825 feature by default. When enabled, memory and cache locality will
1826 be impacted.
1827
1828config CPU_HOTPLUG_STATE_CONTROL
1829 bool "Enable CPU hotplug state control"
1830 depends on DEBUG_KERNEL
1831 depends on HOTPLUG_CPU
1832 default n
1833 help
1834 Allows to write steps between "offline" and "online" to the CPUs
1835 sysfs target file so states can be stepped granular. This is a debug
1836 option for now as the hotplug machinery cannot be stopped and
1837 restarted at arbitrary points yet.
1838
1839 Say N if your are unsure.
1840
1841config LATENCYTOP
1842 bool "Latency measuring infrastructure"
1843 depends on DEBUG_KERNEL
1844 depends on STACKTRACE_SUPPORT
1845 depends on PROC_FS
1846 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1847 select KALLSYMS
1848 select KALLSYMS_ALL
1849 select STACKTRACE
1850 select SCHEDSTATS
1851 help
1852 Enable this option if you want to use the LatencyTOP tool
1853 to find out which userspace is blocking on what kernel operations.
1854
1855config DEBUG_CGROUP_REF
1856 bool "Disable inlining of cgroup css reference count functions"
1857 depends on DEBUG_KERNEL
1858 depends on CGROUPS
1859 depends on KPROBES
1860 default n
1861 help
1862 Force cgroup css reference count functions to not be inlined so
1863 that they can be kprobed for debugging.
1864
1865source "kernel/trace/Kconfig"
1866
1867config PROVIDE_OHCI1394_DMA_INIT
1868 bool "Remote debugging over FireWire early on boot"
1869 depends on PCI && X86
1870 help
1871 If you want to debug problems which hang or crash the kernel early
1872 on boot and the crashing machine has a FireWire port, you can use
1873 this feature to remotely access the memory of the crashed machine
1874 over FireWire. This employs remote DMA as part of the OHCI1394
1875 specification which is now the standard for FireWire controllers.
1876
1877 With remote DMA, you can monitor the printk buffer remotely using
1878 firescope and access all memory below 4GB using fireproxy from gdb.
1879 Even controlling a kernel debugger is possible using remote DMA.
1880
1881 Usage:
1882
1883 If ohci1394_dma=early is used as boot parameter, it will initialize
1884 all OHCI1394 controllers which are found in the PCI config space.
1885
1886 As all changes to the FireWire bus such as enabling and disabling
1887 devices cause a bus reset and thereby disable remote DMA for all
1888 devices, be sure to have the cable plugged and FireWire enabled on
1889 the debugging host before booting the debug target for debugging.
1890
1891 This code (~1k) is freed after boot. By then, the firewire stack
1892 in charge of the OHCI-1394 controllers should be used instead.
1893
1894 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1895
1896source "samples/Kconfig"
1897
1898config ARCH_HAS_DEVMEM_IS_ALLOWED
1899 bool
1900
1901config STRICT_DEVMEM
1902 bool "Filter access to /dev/mem"
1903 depends on MMU && DEVMEM
1904 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1905 default y if PPC || X86 || ARM64 || S390
1906 help
1907 If this option is disabled, you allow userspace (root) access to all
1908 of memory, including kernel and userspace memory. Accidental
1909 access to this is obviously disastrous, but specific access can
1910 be used by people debugging the kernel. Note that with PAT support
1911 enabled, even in this case there are restrictions on /dev/mem
1912 use due to the cache aliasing requirements.
1913
1914 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1915 file only allows userspace access to PCI space and the BIOS code and
1916 data regions. This is sufficient for dosemu and X and all common
1917 users of /dev/mem.
1918
1919 If in doubt, say Y.
1920
1921config IO_STRICT_DEVMEM
1922 bool "Filter I/O access to /dev/mem"
1923 depends on STRICT_DEVMEM
1924 help
1925 If this option is disabled, you allow userspace (root) access to all
1926 io-memory regardless of whether a driver is actively using that
1927 range. Accidental access to this is obviously disastrous, but
1928 specific access can be used by people debugging kernel drivers.
1929
1930 If this option is switched on, the /dev/mem file only allows
1931 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1932 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1933 if the driver using a given range cannot be disabled.
1934
1935 If in doubt, say Y.
1936
1937menu "$(SRCARCH) Debugging"
1938
1939source "arch/$(SRCARCH)/Kconfig.debug"
1940
1941endmenu
1942
1943menu "Kernel Testing and Coverage"
1944
1945source "lib/kunit/Kconfig"
1946
1947config NOTIFIER_ERROR_INJECTION
1948 tristate "Notifier error injection"
1949 depends on DEBUG_KERNEL
1950 select DEBUG_FS
1951 help
1952 This option provides the ability to inject artificial errors to
1953 specified notifier chain callbacks. It is useful to test the error
1954 handling of notifier call chain failures.
1955
1956 Say N if unsure.
1957
1958config PM_NOTIFIER_ERROR_INJECT
1959 tristate "PM notifier error injection module"
1960 depends on PM && NOTIFIER_ERROR_INJECTION
1961 default m if PM_DEBUG
1962 help
1963 This option provides the ability to inject artificial errors to
1964 PM notifier chain callbacks. It is controlled through debugfs
1965 interface /sys/kernel/debug/notifier-error-inject/pm
1966
1967 If the notifier call chain should be failed with some events
1968 notified, write the error code to "actions/<notifier event>/error".
1969
1970 Example: Inject PM suspend error (-12 = -ENOMEM)
1971
1972 # cd /sys/kernel/debug/notifier-error-inject/pm/
1973 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1974 # echo mem > /sys/power/state
1975 bash: echo: write error: Cannot allocate memory
1976
1977 To compile this code as a module, choose M here: the module will
1978 be called pm-notifier-error-inject.
1979
1980 If unsure, say N.
1981
1982config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1983 tristate "OF reconfig notifier error injection module"
1984 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1985 help
1986 This option provides the ability to inject artificial errors to
1987 OF reconfig notifier chain callbacks. It is controlled
1988 through debugfs interface under
1989 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1990
1991 If the notifier call chain should be failed with some events
1992 notified, write the error code to "actions/<notifier event>/error".
1993
1994 To compile this code as a module, choose M here: the module will
1995 be called of-reconfig-notifier-error-inject.
1996
1997 If unsure, say N.
1998
1999config NETDEV_NOTIFIER_ERROR_INJECT
2000 tristate "Netdev notifier error injection module"
2001 depends on NET && NOTIFIER_ERROR_INJECTION
2002 help
2003 This option provides the ability to inject artificial errors to
2004 netdevice notifier chain callbacks. It is controlled through debugfs
2005 interface /sys/kernel/debug/notifier-error-inject/netdev
2006
2007 If the notifier call chain should be failed with some events
2008 notified, write the error code to "actions/<notifier event>/error".
2009
2010 Example: Inject netdevice mtu change error (-22 = -EINVAL)
2011
2012 # cd /sys/kernel/debug/notifier-error-inject/netdev
2013 # echo -22 > actions/NETDEV_CHANGEMTU/error
2014 # ip link set eth0 mtu 1024
2015 RTNETLINK answers: Invalid argument
2016
2017 To compile this code as a module, choose M here: the module will
2018 be called netdev-notifier-error-inject.
2019
2020 If unsure, say N.
2021
2022config FUNCTION_ERROR_INJECTION
2023 bool "Fault-injections of functions"
2024 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
2025 help
2026 Add fault injections into various functions that are annotated with
2027 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
2028 value of these functions. This is useful to test error paths of code.
2029
2030 If unsure, say N
2031
2032config FAULT_INJECTION
2033 bool "Fault-injection framework"
2034 depends on DEBUG_KERNEL
2035 help
2036 Provide fault-injection framework.
2037 For more details, see Documentation/fault-injection/.
2038
2039config FAILSLAB
2040 bool "Fault-injection capability for kmalloc"
2041 depends on FAULT_INJECTION
2042 help
2043 Provide fault-injection capability for kmalloc.
2044
2045config FAIL_PAGE_ALLOC
2046 bool "Fault-injection capability for alloc_pages()"
2047 depends on FAULT_INJECTION
2048 help
2049 Provide fault-injection capability for alloc_pages().
2050
2051config FAULT_INJECTION_USERCOPY
2052 bool "Fault injection capability for usercopy functions"
2053 depends on FAULT_INJECTION
2054 help
2055 Provides fault-injection capability to inject failures
2056 in usercopy functions (copy_from_user(), get_user(), ...).
2057
2058config FAIL_MAKE_REQUEST
2059 bool "Fault-injection capability for disk IO"
2060 depends on FAULT_INJECTION && BLOCK
2061 help
2062 Provide fault-injection capability for disk IO.
2063
2064config FAIL_IO_TIMEOUT
2065 bool "Fault-injection capability for faking disk interrupts"
2066 depends on FAULT_INJECTION && BLOCK
2067 help
2068 Provide fault-injection capability on end IO handling. This
2069 will make the block layer "forget" an interrupt as configured,
2070 thus exercising the error handling.
2071
2072 Only works with drivers that use the generic timeout handling,
2073 for others it won't do anything.
2074
2075config FAIL_FUTEX
2076 bool "Fault-injection capability for futexes"
2077 select DEBUG_FS
2078 depends on FAULT_INJECTION && FUTEX
2079 help
2080 Provide fault-injection capability for futexes.
2081
2082config FAULT_INJECTION_DEBUG_FS
2083 bool "Debugfs entries for fault-injection capabilities"
2084 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2085 help
2086 Enable configuration of fault-injection capabilities via debugfs.
2087
2088config FAIL_FUNCTION
2089 bool "Fault-injection capability for functions"
2090 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2091 help
2092 Provide function-based fault-injection capability.
2093 This will allow you to override a specific function with a return
2094 with given return value. As a result, function caller will see
2095 an error value and have to handle it. This is useful to test the
2096 error handling in various subsystems.
2097
2098config FAIL_MMC_REQUEST
2099 bool "Fault-injection capability for MMC IO"
2100 depends on FAULT_INJECTION_DEBUG_FS && MMC
2101 help
2102 Provide fault-injection capability for MMC IO.
2103 This will make the mmc core return data errors. This is
2104 useful to test the error handling in the mmc block device
2105 and to test how the mmc host driver handles retries from
2106 the block device.
2107
2108config FAIL_SUNRPC
2109 bool "Fault-injection capability for SunRPC"
2110 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2111 help
2112 Provide fault-injection capability for SunRPC and
2113 its consumers.
2114
2115config FAIL_SKB_REALLOC
2116 bool "Fault-injection capability forcing skb to reallocate"
2117 depends on FAULT_INJECTION_DEBUG_FS
2118 help
2119 Provide fault-injection capability that forces the skb to be
2120 reallocated, catching possible invalid pointers to the skb.
2121
2122 For more information, check
2123 Documentation/fault-injection/fault-injection.rst
2124
2125config FAULT_INJECTION_CONFIGFS
2126 bool "Configfs interface for fault-injection capabilities"
2127 depends on FAULT_INJECTION
2128 select CONFIGFS_FS
2129 help
2130 This option allows configfs-based drivers to dynamically configure
2131 fault-injection via configfs. Each parameter for driver-specific
2132 fault-injection can be made visible as a configfs attribute in a
2133 configfs group.
2134
2135
2136config FAULT_INJECTION_STACKTRACE_FILTER
2137 bool "stacktrace filter for fault-injection capabilities"
2138 depends on FAULT_INJECTION
2139 depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
2140 select STACKTRACE
2141 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2142 help
2143 Provide stacktrace filter for fault-injection capabilities
2144
2145config ARCH_HAS_KCOV
2146 bool
2147 help
2148 An architecture should select this when it can successfully
2149 build and run with CONFIG_KCOV. This typically requires
2150 disabling instrumentation for some early boot code.
2151
2152config KCOV
2153 bool "Code coverage for fuzzing"
2154 depends on ARCH_HAS_KCOV
2155 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2156 GCC_VERSION >= 120000 || CC_IS_CLANG
2157 select DEBUG_FS
2158 select OBJTOOL if HAVE_NOINSTR_HACK
2159 help
2160 KCOV exposes kernel code coverage information in a form suitable
2161 for coverage-guided fuzzing (randomized testing).
2162
2163 For more details, see Documentation/dev-tools/kcov.rst.
2164
2165config KCOV_ENABLE_COMPARISONS
2166 bool "Enable comparison operands collection by KCOV"
2167 depends on KCOV
2168 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2169 help
2170 KCOV also exposes operands of every comparison in the instrumented
2171 code along with operand sizes and PCs of the comparison instructions.
2172 These operands can be used by fuzzing engines to improve the quality
2173 of fuzzing coverage.
2174
2175config KCOV_INSTRUMENT_ALL
2176 bool "Instrument all code by default"
2177 depends on KCOV
2178 default y
2179 help
2180 If you are doing generic system call fuzzing (like e.g. syzkaller),
2181 then you will want to instrument the whole kernel and you should
2182 say y here. If you are doing more targeted fuzzing (like e.g.
2183 filesystem fuzzing with AFL) then you will want to enable coverage
2184 for more specific subsets of files, and should say n here.
2185
2186config KCOV_IRQ_AREA_SIZE
2187 hex "Size of interrupt coverage collection area in words"
2188 depends on KCOV
2189 default 0x40000
2190 help
2191 KCOV uses preallocated per-cpu areas to collect coverage from
2192 soft interrupts. This specifies the size of those areas in the
2193 number of unsigned long words.
2194
2195config KCOV_SELFTEST
2196 bool "Perform short selftests on boot"
2197 depends on KCOV
2198 help
2199 Run short KCOV coverage collection selftests on boot.
2200 On test failure, causes the kernel to panic. Recommended to be
2201 enabled, ensuring critical functionality works as intended.
2202
2203menuconfig RUNTIME_TESTING_MENU
2204 bool "Runtime Testing"
2205 default y
2206
2207if RUNTIME_TESTING_MENU
2208
2209config TEST_DHRY
2210 tristate "Dhrystone benchmark test"
2211 help
2212 Enable this to include the Dhrystone 2.1 benchmark. This test
2213 calculates the number of Dhrystones per second, and the number of
2214 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2215 by 1757 (the number of Dhrystones per second obtained on the VAX
2216 11/780, nominally a 1 MIPS machine).
2217
2218 To run the benchmark, it needs to be enabled explicitly, either from
2219 the kernel command line (when built-in), or from userspace (when
2220 built-in or modular).
2221
2222 Run once during kernel boot:
2223
2224 test_dhry.run
2225
2226 Set number of iterations from kernel command line:
2227
2228 test_dhry.iterations=<n>
2229
2230 Set number of iterations from userspace:
2231
2232 echo <n> > /sys/module/test_dhry/parameters/iterations
2233
2234 Trigger manual run from userspace:
2235
2236 echo y > /sys/module/test_dhry/parameters/run
2237
2238 If the number of iterations is <= 0, the test will devise a suitable
2239 number of iterations (test runs for at least 2s) automatically.
2240 This process takes ca. 4s.
2241
2242 If unsure, say N.
2243
2244config LKDTM
2245 tristate "Linux Kernel Dump Test Tool Module"
2246 depends on DEBUG_FS
2247 help
2248 This module enables testing of the different dumping mechanisms by
2249 inducing system failures at predefined crash points.
2250 If you don't need it: say N
2251 Choose M here to compile this code as a module. The module will be
2252 called lkdtm.
2253
2254 Documentation on how to use the module can be found in
2255 Documentation/fault-injection/provoke-crashes.rst
2256
2257config CPUMASK_KUNIT_TEST
2258 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2259 depends on KUNIT
2260 default KUNIT_ALL_TESTS
2261 help
2262 Enable to turn on cpumask tests, running at boot or module load time.
2263
2264 For more information on KUnit and unit tests in general, please refer
2265 to the KUnit documentation in Documentation/dev-tools/kunit/.
2266
2267 If unsure, say N.
2268
2269config TEST_LIST_SORT
2270 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2271 depends on KUNIT
2272 default KUNIT_ALL_TESTS
2273 help
2274 Enable this to turn on 'list_sort()' function test. This test is
2275 executed only once during system boot (so affects only boot time),
2276 or at module load time.
2277
2278 If unsure, say N.
2279
2280config TEST_MIN_HEAP
2281 tristate "Min heap test"
2282 depends on DEBUG_KERNEL || m
2283 help
2284 Enable this to turn on min heap function tests. This test is
2285 executed only once during system boot (so affects only boot time),
2286 or at module load time.
2287
2288 If unsure, say N.
2289
2290config TEST_SORT
2291 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2292 depends on KUNIT
2293 default KUNIT_ALL_TESTS
2294 help
2295 This option enables the self-test function of 'sort()' at boot,
2296 or at module load time.
2297
2298 If unsure, say N.
2299
2300config TEST_DIV64
2301 tristate "64bit/32bit division and modulo test"
2302 depends on DEBUG_KERNEL || m
2303 help
2304 Enable this to turn on 'do_div()' function test. This test is
2305 executed only once during system boot (so affects only boot time),
2306 or at module load time.
2307
2308 If unsure, say N.
2309
2310config TEST_MULDIV64
2311 tristate "mul_u64_u64_div_u64() test"
2312 depends on DEBUG_KERNEL || m
2313 help
2314 Enable this to turn on 'mul_u64_u64_div_u64()' function test.
2315 This test is executed only once during system boot (so affects
2316 only boot time), or at module load time.
2317
2318 If unsure, say N.
2319
2320config TEST_IOV_ITER
2321 tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS
2322 depends on KUNIT
2323 depends on MMU
2324 default KUNIT_ALL_TESTS
2325 help
2326 Enable this to turn on testing of the operation of the I/O iterator
2327 (iov_iter). This test is executed only once during system boot (so
2328 affects only boot time), or at module load time.
2329
2330 If unsure, say N.
2331
2332config KPROBES_SANITY_TEST
2333 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2334 depends on DEBUG_KERNEL
2335 depends on KPROBES
2336 depends on KUNIT
2337 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2338 default KUNIT_ALL_TESTS
2339 help
2340 This option provides for testing basic kprobes functionality on
2341 boot. Samples of kprobe and kretprobe are inserted and
2342 verified for functionality.
2343
2344 Say N if you are unsure.
2345
2346config FPROBE_SANITY_TEST
2347 bool "Self test for fprobe"
2348 depends on DEBUG_KERNEL
2349 depends on FPROBE
2350 depends on KUNIT=y
2351 help
2352 This option will enable testing the fprobe when the system boot.
2353 A series of tests are made to verify that the fprobe is functioning
2354 properly.
2355
2356 Say N if you are unsure.
2357
2358config BACKTRACE_SELF_TEST
2359 tristate "Self test for the backtrace code"
2360 depends on DEBUG_KERNEL
2361 help
2362 This option provides a kernel module that can be used to test
2363 the kernel stack backtrace code. This option is not useful
2364 for distributions or general kernels, but only for kernel
2365 developers working on architecture code.
2366
2367 Note that if you want to also test saved backtraces, you will
2368 have to enable STACKTRACE as well.
2369
2370 Say N if you are unsure.
2371
2372config TEST_REF_TRACKER
2373 tristate "Self test for reference tracker"
2374 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2375 select REF_TRACKER
2376 help
2377 This option provides a kernel module performing tests
2378 using reference tracker infrastructure.
2379
2380 Say N if you are unsure.
2381
2382config RBTREE_TEST
2383 tristate "Red-Black tree test"
2384 depends on DEBUG_KERNEL
2385 help
2386 A benchmark measuring the performance of the rbtree library.
2387 Also includes rbtree invariant checks.
2388
2389config REED_SOLOMON_TEST
2390 tristate "Reed-Solomon library test"
2391 depends on DEBUG_KERNEL || m
2392 select REED_SOLOMON
2393 select REED_SOLOMON_ENC16
2394 select REED_SOLOMON_DEC16
2395 help
2396 This option enables the self-test function of rslib at boot,
2397 or at module load time.
2398
2399 If unsure, say N.
2400
2401config INTERVAL_TREE_TEST
2402 tristate "Interval tree test"
2403 depends on DEBUG_KERNEL
2404 select INTERVAL_TREE
2405 help
2406 A benchmark measuring the performance of the interval tree library
2407
2408config PERCPU_TEST
2409 tristate "Per cpu operations test"
2410 depends on m && DEBUG_KERNEL
2411 help
2412 Enable this option to build test module which validates per-cpu
2413 operations.
2414
2415 If unsure, say N.
2416
2417config ATOMIC64_SELFTEST
2418 tristate "Perform an atomic64_t self-test"
2419 help
2420 Enable this option to test the atomic64_t functions at boot or
2421 at module load time.
2422
2423 If unsure, say N.
2424
2425config ASYNC_RAID6_TEST
2426 tristate "Self test for hardware accelerated raid6 recovery"
2427 depends on ASYNC_RAID6_RECOV
2428 select ASYNC_MEMCPY
2429 help
2430 This is a one-shot self test that permutes through the
2431 recovery of all the possible two disk failure scenarios for a
2432 N-disk array. Recovery is performed with the asynchronous
2433 raid6 recovery routines, and will optionally use an offload
2434 engine if one is available.
2435
2436 If unsure, say N.
2437
2438config TEST_HEXDUMP
2439 tristate "Test functions located in the hexdump module at runtime"
2440
2441config PRINTF_KUNIT_TEST
2442 tristate "KUnit test printf() family of functions at runtime" if !KUNIT_ALL_TESTS
2443 depends on KUNIT
2444 default KUNIT_ALL_TESTS
2445 help
2446 Enable this option to test the printf functions at runtime.
2447
2448 If unsure, say N.
2449
2450config SCANF_KUNIT_TEST
2451 tristate "KUnit test scanf() family of functions at runtime" if !KUNIT_ALL_TESTS
2452 depends on KUNIT
2453 default KUNIT_ALL_TESTS
2454 help
2455 Enable this option to test the scanf functions at runtime.
2456
2457 If unsure, say N.
2458
2459config SEQ_BUF_KUNIT_TEST
2460 tristate "KUnit test for seq_buf" if !KUNIT_ALL_TESTS
2461 depends on KUNIT
2462 default KUNIT_ALL_TESTS
2463 help
2464 This builds unit tests for the seq_buf library.
2465
2466 If unsure, say N.
2467
2468config STRING_KUNIT_TEST
2469 tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS
2470 depends on KUNIT
2471 default KUNIT_ALL_TESTS
2472
2473config STRING_HELPERS_KUNIT_TEST
2474 tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS
2475 depends on KUNIT
2476 default KUNIT_ALL_TESTS
2477
2478config FFS_KUNIT_TEST
2479 tristate "KUnit test ffs-family functions at runtime" if !KUNIT_ALL_TESTS
2480 depends on KUNIT
2481 default KUNIT_ALL_TESTS
2482 help
2483 This builds KUnit tests for ffs-family bit manipulation functions
2484 including ffs(), __ffs(), fls(), __fls(), fls64(), and __ffs64().
2485
2486 These tests validate mathematical correctness, edge case handling,
2487 and cross-architecture consistency of bit scanning functions.
2488
2489 For more information on KUnit and unit tests in general,
2490 please refer to Documentation/dev-tools/kunit/.
2491
2492config TEST_KSTRTOX
2493 tristate "Test kstrto*() family of functions at runtime"
2494
2495config TEST_BITMAP
2496 tristate "Test bitmap_*() family of functions at runtime"
2497 help
2498 Enable this option to test the bitmap functions at boot.
2499
2500 If unsure, say N.
2501
2502config TEST_UUID
2503 tristate "Test functions located in the uuid module at runtime"
2504
2505config TEST_XARRAY
2506 tristate "Test the XArray code at runtime"
2507
2508config TEST_MAPLE_TREE
2509 tristate "Test the Maple Tree code at runtime or module load"
2510 help
2511 Enable this option to test the maple tree code functions at boot, or
2512 when the module is loaded. Enable "Debug Maple Trees" will enable
2513 more verbose output on failures.
2514
2515 If unsure, say N.
2516
2517config TEST_RHASHTABLE
2518 tristate "Perform selftest on resizable hash table"
2519 help
2520 Enable this option to test the rhashtable functions at boot.
2521
2522 If unsure, say N.
2523
2524config TEST_IDA
2525 tristate "Perform selftest on IDA functions"
2526
2527config TEST_MISC_MINOR
2528 bool "miscdevice KUnit test" if !KUNIT_ALL_TESTS
2529 depends on KUNIT=y
2530 default KUNIT_ALL_TESTS
2531 help
2532 Kunit test for miscdevice API, specially its behavior in respect to
2533 static and dynamic minor numbers.
2534
2535 KUnit tests run during boot and output the results to the debug log
2536 in TAP format (https://testanything.org/). Only useful for kernel devs
2537 running the KUnit test harness, and not intended for inclusion into a
2538 production build.
2539
2540 For more information on KUnit and unit tests in general please refer
2541 to the KUnit documentation in Documentation/dev-tools/kunit/.
2542
2543 If unsure, say N.
2544
2545config TEST_PARMAN
2546 tristate "Perform selftest on priority array manager"
2547 depends on PARMAN
2548 help
2549 Enable this option to test priority array manager on boot
2550 (or module load).
2551
2552 If unsure, say N.
2553
2554config TEST_IRQ_TIMINGS
2555 bool "IRQ timings selftest"
2556 depends on IRQ_TIMINGS
2557 help
2558 Enable this option to test the irq timings code on boot.
2559
2560 If unsure, say N.
2561
2562config TEST_LKM
2563 tristate "Test module loading with 'hello world' module"
2564 depends on m
2565 help
2566 This builds the "test_module" module that emits "Hello, world"
2567 on printk when loaded. It is designed to be used for basic
2568 evaluation of the module loading subsystem (for example when
2569 validating module verification). It lacks any extra dependencies,
2570 and will not normally be loaded by the system unless explicitly
2571 requested by name.
2572
2573 If unsure, say N.
2574
2575config TEST_BITOPS
2576 tristate "Test module for compilation of bitops operations"
2577 help
2578 This builds the "test_bitops" module that is much like the
2579 TEST_LKM module except that it does a basic exercise of the
2580 set/clear_bit macros and get_count_order/long to make sure there are
2581 no compiler warnings from C=1 sparse checker or -Wextra
2582 compilations. It has no dependencies and doesn't run or load unless
2583 explicitly requested by name. for example: modprobe test_bitops.
2584
2585 If unsure, say N.
2586
2587config TEST_VMALLOC
2588 tristate "Test module for stress/performance analysis of vmalloc allocator"
2589 default n
2590 depends on MMU
2591 help
2592 This builds the "test_vmalloc" module that should be used for
2593 stress and performance analysis. So, any new change for vmalloc
2594 subsystem can be evaluated from performance and stability point
2595 of view.
2596
2597 If unsure, say N.
2598
2599config TEST_BPF
2600 tristate "Test BPF filter functionality"
2601 depends on m && NET
2602 help
2603 This builds the "test_bpf" module that runs various test vectors
2604 against the BPF interpreter or BPF JIT compiler depending on the
2605 current setting. This is in particular useful for BPF JIT compiler
2606 development, but also to run regression tests against changes in
2607 the interpreter code. It also enables test stubs for eBPF maps and
2608 verifier used by user space verifier testsuite.
2609
2610 If unsure, say N.
2611
2612config FIND_BIT_BENCHMARK
2613 tristate "Test find_bit functions"
2614 help
2615 This builds the "test_find_bit" module that measure find_*_bit()
2616 functions performance.
2617
2618 If unsure, say N.
2619
2620config FIND_BIT_BENCHMARK_RUST
2621 tristate "Test find_bit functions in Rust"
2622 depends on RUST
2623 help
2624 This builds the "find_bit_benchmark_rust" module. It is a micro
2625 benchmark that measures the performance of Rust functions that
2626 correspond to the find_*_bit() operations in C. It follows the
2627 FIND_BIT_BENCHMARK closely but will in general not yield same
2628 numbers due to extra bounds checks and overhead of foreign
2629 function calls.
2630
2631 If unsure, say N.
2632
2633config TEST_FIRMWARE
2634 tristate "Test firmware loading via userspace interface"
2635 depends on FW_LOADER
2636 help
2637 This builds the "test_firmware" module that creates a userspace
2638 interface for testing firmware loading. This can be used to
2639 control the triggering of firmware loading without needing an
2640 actual firmware-using device. The contents can be rechecked by
2641 userspace.
2642
2643 If unsure, say N.
2644
2645config TEST_SYSCTL
2646 tristate "sysctl test driver"
2647 depends on PROC_SYSCTL
2648 help
2649 This builds the "test_sysctl" module. This driver enables to test the
2650 proc sysctl interfaces available to drivers safely without affecting
2651 production knobs which might alter system functionality.
2652
2653 If unsure, say N.
2654
2655config BITFIELD_KUNIT
2656 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2657 depends on KUNIT
2658 default KUNIT_ALL_TESTS
2659 help
2660 Enable this option to test the bitfield functions at boot.
2661
2662 KUnit tests run during boot and output the results to the debug log
2663 in TAP format (http://testanything.org/). Only useful for kernel devs
2664 running the KUnit test harness, and not intended for inclusion into a
2665 production build.
2666
2667 For more information on KUnit and unit tests in general please refer
2668 to the KUnit documentation in Documentation/dev-tools/kunit/.
2669
2670 If unsure, say N.
2671
2672config CHECKSUM_KUNIT
2673 tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2674 depends on KUNIT
2675 default KUNIT_ALL_TESTS
2676 help
2677 Enable this option to test the checksum functions at boot.
2678
2679 KUnit tests run during boot and output the results to the debug log
2680 in TAP format (http://testanything.org/). Only useful for kernel devs
2681 running the KUnit test harness, and not intended for inclusion into a
2682 production build.
2683
2684 For more information on KUnit and unit tests in general please refer
2685 to the KUnit documentation in Documentation/dev-tools/kunit/.
2686
2687 If unsure, say N.
2688
2689config UTIL_MACROS_KUNIT
2690 tristate "KUnit test util_macros.h functions at runtime" if !KUNIT_ALL_TESTS
2691 depends on KUNIT
2692 default KUNIT_ALL_TESTS
2693 help
2694 Enable this option to test the util_macros.h function at boot.
2695
2696 KUnit tests run during boot and output the results to the debug log
2697 in TAP format (http://testanything.org/). Only useful for kernel devs
2698 running the KUnit test harness, and not intended for inclusion into a
2699 production build.
2700
2701 For more information on KUnit and unit tests in general please refer
2702 to the KUnit documentation in Documentation/dev-tools/kunit/.
2703
2704 If unsure, say N.
2705
2706config HASH_KUNIT_TEST
2707 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2708 depends on KUNIT
2709 default KUNIT_ALL_TESTS
2710 help
2711 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2712 integer (<linux/hash.h>) hash functions on boot.
2713
2714 KUnit tests run during boot and output the results to the debug log
2715 in TAP format (https://testanything.org/). Only useful for kernel devs
2716 running the KUnit test harness, and not intended for inclusion into a
2717 production build.
2718
2719 For more information on KUnit and unit tests in general please refer
2720 to the KUnit documentation in Documentation/dev-tools/kunit/.
2721
2722 This is intended to help people writing architecture-specific
2723 optimized versions. If unsure, say N.
2724
2725config RESOURCE_KUNIT_TEST
2726 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2727 depends on KUNIT
2728 default KUNIT_ALL_TESTS
2729 select GET_FREE_REGION
2730 help
2731 This builds the resource API unit test.
2732 Tests the logic of API provided by resource.c and ioport.h.
2733 For more information on KUnit and unit tests in general please refer
2734 to the KUnit documentation in Documentation/dev-tools/kunit/.
2735
2736 If unsure, say N.
2737
2738config SYSCTL_KUNIT_TEST
2739 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2740 depends on KUNIT
2741 default KUNIT_ALL_TESTS
2742 help
2743 This builds the proc sysctl unit test, which runs on boot.
2744 Tests the API contract and implementation correctness of sysctl.
2745 For more information on KUnit and unit tests in general please refer
2746 to the KUnit documentation in Documentation/dev-tools/kunit/.
2747
2748 If unsure, say N.
2749
2750config KFIFO_KUNIT_TEST
2751 tristate "KUnit Test for the generic kernel FIFO implementation" if !KUNIT_ALL_TESTS
2752 depends on KUNIT
2753 default KUNIT_ALL_TESTS
2754 help
2755 This builds the generic FIFO implementation KUnit test suite.
2756 It tests that the API and basic functionality of the kfifo type
2757 and associated macros.
2758
2759 For more information on KUnit and unit tests in general please refer
2760 to the KUnit documentation in Documentation/dev-tools/kunit/.
2761
2762 If unsure, say N.
2763
2764config LIST_KUNIT_TEST
2765 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2766 depends on KUNIT
2767 default KUNIT_ALL_TESTS
2768 help
2769 This builds the linked list KUnit test suite.
2770 It tests that the API and basic functionality of the list_head type
2771 and associated macros.
2772
2773 KUnit tests run during boot and output the results to the debug log
2774 in TAP format (https://testanything.org/). Only useful for kernel devs
2775 running the KUnit test harness, and not intended for inclusion into a
2776 production build.
2777
2778 For more information on KUnit and unit tests in general please refer
2779 to the KUnit documentation in Documentation/dev-tools/kunit/.
2780
2781 If unsure, say N.
2782
2783config HASHTABLE_KUNIT_TEST
2784 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2785 depends on KUNIT
2786 default KUNIT_ALL_TESTS
2787 help
2788 This builds the hashtable KUnit test suite.
2789 It tests the basic functionality of the API defined in
2790 include/linux/hashtable.h. For more information on KUnit and
2791 unit tests in general please refer to the KUnit documentation
2792 in Documentation/dev-tools/kunit/.
2793
2794 If unsure, say N.
2795
2796config LINEAR_RANGES_TEST
2797 tristate "KUnit test for linear_ranges"
2798 depends on KUNIT
2799 select LINEAR_RANGES
2800 help
2801 This builds the linear_ranges unit test, which runs on boot.
2802 Tests the linear_ranges logic correctness.
2803 For more information on KUnit and unit tests in general please refer
2804 to the KUnit documentation in Documentation/dev-tools/kunit/.
2805
2806 If unsure, say N.
2807
2808config CMDLINE_KUNIT_TEST
2809 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2810 depends on KUNIT
2811 default KUNIT_ALL_TESTS
2812 help
2813 This builds the cmdline API unit test.
2814 Tests the logic of API provided by cmdline.c.
2815 For more information on KUnit and unit tests in general please refer
2816 to the KUnit documentation in Documentation/dev-tools/kunit/.
2817
2818 If unsure, say N.
2819
2820config BASE64_KUNIT
2821 tristate "KUnit test for base64 decoding and encoding" if !KUNIT_ALL_TESTS
2822 depends on KUNIT
2823 default KUNIT_ALL_TESTS
2824 help
2825 This builds the base64 unit tests.
2826
2827 The tests cover the encoding and decoding logic of Base64 functions
2828 in the kernel.
2829 In addition to correctness checks, simple performance benchmarks
2830 for both encoding and decoding are also included.
2831
2832 For more information on KUnit and unit tests in general please refer
2833 to the KUnit documentation in Documentation/dev-tools/kunit/.
2834
2835 If unsure, say N.
2836
2837config BITS_TEST
2838 tristate "KUnit test for bit functions and macros" if !KUNIT_ALL_TESTS
2839 depends on KUNIT
2840 default KUNIT_ALL_TESTS
2841 help
2842 This builds the bits unit test.
2843 Tests the logic of macros defined in bits.h.
2844 For more information on KUnit and unit tests in general please refer
2845 to the KUnit documentation in Documentation/dev-tools/kunit/.
2846
2847 If unsure, say N.
2848
2849config SLUB_KUNIT_TEST
2850 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2851 depends on SLUB_DEBUG && KUNIT
2852 default KUNIT_ALL_TESTS
2853 help
2854 This builds SLUB allocator unit test.
2855 Tests SLUB cache debugging functionality.
2856 For more information on KUnit and unit tests in general please refer
2857 to the KUnit documentation in Documentation/dev-tools/kunit/.
2858
2859 If unsure, say N.
2860
2861config RATIONAL_KUNIT_TEST
2862 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2863 depends on KUNIT && RATIONAL
2864 default KUNIT_ALL_TESTS
2865 help
2866 This builds the rational math unit test.
2867 For more information on KUnit and unit tests in general please refer
2868 to the KUnit documentation in Documentation/dev-tools/kunit/.
2869
2870 If unsure, say N.
2871
2872config MEMCPY_KUNIT_TEST
2873 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2874 depends on KUNIT
2875 default KUNIT_ALL_TESTS
2876 help
2877 Builds unit tests for memcpy(), memmove(), and memset() functions.
2878 For more information on KUnit and unit tests in general please refer
2879 to the KUnit documentation in Documentation/dev-tools/kunit/.
2880
2881 If unsure, say N.
2882
2883config IS_SIGNED_TYPE_KUNIT_TEST
2884 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2885 depends on KUNIT
2886 default KUNIT_ALL_TESTS
2887 help
2888 Builds unit tests for the is_signed_type() macro.
2889
2890 For more information on KUnit and unit tests in general please refer
2891 to the KUnit documentation in Documentation/dev-tools/kunit/.
2892
2893 If unsure, say N.
2894
2895config OVERFLOW_KUNIT_TEST
2896 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2897 depends on KUNIT
2898 default KUNIT_ALL_TESTS
2899 help
2900 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2901 related functions.
2902
2903 For more information on KUnit and unit tests in general please refer
2904 to the KUnit documentation in Documentation/dev-tools/kunit/.
2905
2906 If unsure, say N.
2907
2908config RANDSTRUCT_KUNIT_TEST
2909 tristate "Test randstruct structure layout randomization at runtime" if !KUNIT_ALL_TESTS
2910 depends on KUNIT
2911 default KUNIT_ALL_TESTS
2912 help
2913 Builds unit tests for the checking CONFIG_RANDSTRUCT=y, which
2914 randomizes structure layouts.
2915
2916config STACKINIT_KUNIT_TEST
2917 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2918 depends on KUNIT
2919 default KUNIT_ALL_TESTS
2920 help
2921 Test if the kernel is zero-initializing stack variables and
2922 padding. Coverage is controlled by compiler flags,
2923 CONFIG_INIT_STACK_ALL_PATTERN or CONFIG_INIT_STACK_ALL_ZERO.
2924
2925config FORTIFY_KUNIT_TEST
2926 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2927 depends on KUNIT
2928 default KUNIT_ALL_TESTS
2929 help
2930 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2931 by the str*() and mem*() family of functions. For testing runtime
2932 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2933
2934config LONGEST_SYM_KUNIT_TEST
2935 tristate "Test the longest symbol possible" if !KUNIT_ALL_TESTS
2936 depends on KUNIT && KPROBES
2937 depends on !PREFIX_SYMBOLS && !CFI && !GCOV_KERNEL
2938 default KUNIT_ALL_TESTS
2939 help
2940 Tests the longest symbol possible
2941
2942 If unsure, say N.
2943
2944config HW_BREAKPOINT_KUNIT_TEST
2945 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2946 depends on HAVE_HW_BREAKPOINT
2947 depends on KUNIT=y
2948 default KUNIT_ALL_TESTS
2949 help
2950 Tests for hw_breakpoint constraints accounting.
2951
2952 If unsure, say N.
2953
2954config SIPHASH_KUNIT_TEST
2955 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2956 depends on KUNIT
2957 default KUNIT_ALL_TESTS
2958 help
2959 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2960 functions on boot (or module load).
2961
2962 This is intended to help people writing architecture-specific
2963 optimized versions. If unsure, say N.
2964
2965config USERCOPY_KUNIT_TEST
2966 tristate "KUnit Test for user/kernel boundary protections"
2967 depends on KUNIT
2968 default KUNIT_ALL_TESTS
2969 help
2970 This builds the "usercopy_kunit" module that runs sanity checks
2971 on the copy_to/from_user infrastructure, making sure basic
2972 user/kernel boundary testing is working.
2973
2974config BLACKHOLE_DEV_KUNIT_TEST
2975 tristate "Test blackhole netdev functionality" if !KUNIT_ALL_TESTS
2976 depends on NET
2977 depends on KUNIT
2978 default KUNIT_ALL_TESTS
2979 help
2980 This builds the "blackhole_dev_kunit" module that validates the
2981 data path through this blackhole netdev.
2982
2983 If unsure, say N.
2984
2985config TEST_UDELAY
2986 tristate "udelay test driver"
2987 help
2988 This builds the "udelay_test" module that helps to make sure
2989 that udelay() is working properly.
2990
2991 If unsure, say N.
2992
2993config TEST_STATIC_KEYS
2994 tristate "Test static keys"
2995 depends on m
2996 help
2997 Test the static key interfaces.
2998
2999 If unsure, say N.
3000
3001config TEST_DYNAMIC_DEBUG
3002 tristate "Test DYNAMIC_DEBUG"
3003 depends on DYNAMIC_DEBUG
3004 help
3005 This module registers a tracer callback to count enabled
3006 pr_debugs in a 'do_debugging' function, then alters their
3007 enablements, calls the function, and compares counts.
3008
3009 If unsure, say N.
3010
3011config TEST_KMOD
3012 tristate "kmod stress tester"
3013 depends on m
3014 select TEST_LKM
3015 help
3016 Test the kernel's module loading mechanism: kmod. kmod implements
3017 support to load modules using the Linux kernel's usermode helper.
3018 This test provides a series of tests against kmod.
3019
3020 Although technically you can either build test_kmod as a module or
3021 into the kernel we disallow building it into the kernel since
3022 it stress tests request_module() and this will very likely cause
3023 some issues by taking over precious threads available from other
3024 module load requests, ultimately this could be fatal.
3025
3026 To run tests run:
3027
3028 tools/testing/selftests/kmod/kmod.sh --help
3029
3030 If unsure, say N.
3031
3032config TEST_RUNTIME
3033 bool
3034
3035config TEST_RUNTIME_MODULE
3036 bool
3037
3038config TEST_KALLSYMS
3039 tristate "module kallsyms find_symbol() test"
3040 depends on m
3041 select TEST_RUNTIME
3042 select TEST_RUNTIME_MODULE
3043 select TEST_KALLSYMS_A
3044 select TEST_KALLSYMS_B
3045 select TEST_KALLSYMS_C
3046 select TEST_KALLSYMS_D
3047 help
3048 This allows us to stress test find_symbol() through the kallsyms
3049 used to place symbols on the kernel ELF kallsyms and modules kallsyms
3050 where we place kernel symbols such as exported symbols.
3051
3052 We have four test modules:
3053
3054 A: has KALLSYSMS_NUMSYMS exported symbols
3055 B: uses one of A's symbols
3056 C: adds KALLSYMS_SCALE_FACTOR * KALLSYSMS_NUMSYMS exported
3057 D: adds 2 * the symbols than C
3058
3059 We stress test find_symbol() through two means:
3060
3061 1) Upon load of B it will trigger simplify_symbols() to look for the
3062 one symbol it uses from the module A with tons of symbols. This is an
3063 indirect way for us to have B call resolve_symbol_wait() upon module
3064 load. This will eventually call find_symbol() which will eventually
3065 try to find the symbols used with find_exported_symbol_in_section().
3066 find_exported_symbol_in_section() uses bsearch() so a binary search
3067 for each symbol. Binary search will at worst be O(log(n)) so the
3068 larger TEST_MODULE_KALLSYSMS the worse the search.
3069
3070 2) The selftests should load C first, before B. Upon B's load towards
3071 the end right before we call module B's init routine we get
3072 complete_formation() called on the module. That will first check
3073 for duplicate symbols with the call to verify_exported_symbols().
3074 That is when we'll force iteration on module C's insane symbol list.
3075 Since it has 10 * KALLSYMS_NUMSYMS it means we can first test
3076 just loading B without C. The amount of time it takes to load C Vs
3077 B can give us an idea of the impact growth of the symbol space and
3078 give us projection. Module A only uses one symbol from B so to allow
3079 this scaling in module C to be proportional, if it used more symbols
3080 then the first test would be doing more and increasing just the
3081 search space would be slightly different. The last module, module D
3082 will just increase the search space by twice the number of symbols in
3083 C so to allow for full projects.
3084
3085 tools/testing/selftests/module/find_symbol.sh
3086
3087 The current defaults will incur a build delay of about 7 minutes
3088 on an x86_64 with only 8 cores. Enable this only if you want to
3089 stress test find_symbol() with thousands of symbols. At the same
3090 time this is also useful to test building modules with thousands of
3091 symbols, and if BTF is enabled this also stress tests adding BTF
3092 information for each module. Currently enabling many more symbols
3093 will segfault the build system.
3094
3095 If unsure, say N.
3096
3097if TEST_KALLSYMS
3098
3099config TEST_KALLSYMS_A
3100 tristate
3101 depends on m
3102
3103config TEST_KALLSYMS_B
3104 tristate
3105 depends on m
3106
3107config TEST_KALLSYMS_C
3108 tristate
3109 depends on m
3110
3111config TEST_KALLSYMS_D
3112 tristate
3113 depends on m
3114
3115choice
3116 prompt "Kallsym test range"
3117 default TEST_KALLSYMS_LARGE
3118 help
3119 Selecting something other than "Fast" will enable tests which slow
3120 down the build and may crash your build.
3121
3122config TEST_KALLSYMS_FAST
3123 bool "Fast builds"
3124 help
3125 You won't really be testing kallsysms, so this just helps fast builds
3126 when allmodconfig is used..
3127
3128config TEST_KALLSYMS_LARGE
3129 bool "Enable testing kallsyms with large exports"
3130 help
3131 This will enable larger number of symbols. This will slow down
3132 your build considerably.
3133
3134config TEST_KALLSYMS_MAX
3135 bool "Known kallsysms limits"
3136 help
3137 This will enable exports to the point we know we'll start crashing
3138 builds.
3139
3140endchoice
3141
3142config TEST_KALLSYMS_NUMSYMS
3143 int "test kallsyms number of symbols"
3144 range 2 10000
3145 default 2 if TEST_KALLSYMS_FAST
3146 default 100 if TEST_KALLSYMS_LARGE
3147 default 10000 if TEST_KALLSYMS_MAX
3148 help
3149 The number of symbols to create on TEST_KALLSYMS_A, only one of which
3150 module TEST_KALLSYMS_B will use. This also will be used
3151 for how many symbols TEST_KALLSYMS_C will have, scaled up by
3152 TEST_KALLSYMS_SCALE_FACTOR. Note that setting this to 10,000 will
3153 trigger a segfault today, don't use anything close to it unless
3154 you are aware that this should not be used for automated build tests.
3155
3156config TEST_KALLSYMS_SCALE_FACTOR
3157 int "test kallsyms scale factor"
3158 default 8
3159 help
3160 How many more unusued symbols will TEST_KALLSYSMS_C have than
3161 TEST_KALLSYMS_A. If 8, then module C will have 8 * syms
3162 than module A. Then TEST_KALLSYMS_D will have double the amount
3163 of symbols than C so to allow projections.
3164
3165endif # TEST_KALLSYMS
3166
3167config TEST_DEBUG_VIRTUAL
3168 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
3169 depends on DEBUG_VIRTUAL
3170 help
3171 Test the kernel's ability to detect incorrect calls to
3172 virt_to_phys() done against the non-linear part of the
3173 kernel's virtual address map.
3174
3175 If unsure, say N.
3176
3177config TEST_MEMCAT_P
3178 tristate "Test memcat_p() helper function"
3179 help
3180 Test the memcat_p() helper for correctly merging two
3181 pointer arrays together.
3182
3183 If unsure, say N.
3184
3185config TEST_OBJAGG
3186 tristate "Perform selftest on object aggreration manager"
3187 default n
3188 depends on OBJAGG
3189 help
3190 Enable this option to test object aggregation manager on boot
3191 (or module load).
3192
3193config TEST_MEMINIT
3194 tristate "Test heap/page initialization"
3195 help
3196 Test if the kernel is zero-initializing heap and page allocations.
3197 This can be useful to test init_on_alloc and init_on_free features.
3198
3199 If unsure, say N.
3200
3201config TEST_HMM
3202 tristate "Test HMM (Heterogeneous Memory Management)"
3203 depends on TRANSPARENT_HUGEPAGE
3204 depends on DEVICE_PRIVATE
3205 select HMM_MIRROR
3206 select MMU_NOTIFIER
3207 help
3208 This is a pseudo device driver solely for testing HMM.
3209 Say M here if you want to build the HMM test module.
3210 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
3211
3212 If unsure, say N.
3213
3214config TEST_FREE_PAGES
3215 tristate "Test freeing pages"
3216 help
3217 Test that a memory leak does not occur due to a race between
3218 freeing a block of pages and a speculative page reference.
3219 Loading this module is safe if your kernel has the bug fixed.
3220 If the bug is not fixed, it will leak gigabytes of memory and
3221 probably OOM your system.
3222
3223config TEST_FPU
3224 tristate "Test floating point operations in kernel space"
3225 depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL
3226 help
3227 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
3228 which will trigger a sequence of floating point operations. This is used
3229 for self-testing floating point control register setting in
3230 kernel_fpu_begin().
3231
3232 If unsure, say N.
3233
3234config TEST_CLOCKSOURCE_WATCHDOG
3235 tristate "Test clocksource watchdog in kernel space"
3236 depends on CLOCKSOURCE_WATCHDOG
3237 help
3238 Enable this option to create a kernel module that will trigger
3239 a test of the clocksource watchdog. This module may be loaded
3240 via modprobe or insmod in which case it will run upon being
3241 loaded, or it may be built in, in which case it will run
3242 shortly after boot.
3243
3244 If unsure, say N.
3245
3246config TEST_OBJPOOL
3247 tristate "Test module for correctness and stress of objpool"
3248 default n
3249 depends on m && DEBUG_KERNEL
3250 help
3251 This builds the "test_objpool" module that should be used for
3252 correctness verification and concurrent testings of objects
3253 allocation and reclamation.
3254
3255 If unsure, say N.
3256
3257config TEST_KEXEC_HANDOVER
3258 bool "Test for Kexec HandOver"
3259 default n
3260 depends on KEXEC_HANDOVER
3261 help
3262 This option enables test for Kexec HandOver (KHO).
3263 The test consists of two parts: saving kernel data before kexec and
3264 restoring the data after kexec and verifying that it was properly
3265 handed over. This test module creates and saves data on the boot of
3266 the first kernel and restores and verifies the data on the boot of
3267 kexec'ed kernel.
3268
3269 For detailed documentation about KHO, see Documentation/core-api/kho.
3270
3271 To run the test run:
3272
3273 tools/testing/selftests/kho/vmtest.sh -h
3274
3275 If unsure, say N.
3276
3277config RATELIMIT_KUNIT_TEST
3278 tristate "KUnit Test for correctness and stress of ratelimit" if !KUNIT_ALL_TESTS
3279 depends on KUNIT
3280 default KUNIT_ALL_TESTS
3281 help
3282 This builds the "test_ratelimit" module that should be used
3283 for correctness verification and concurrent testings of rate
3284 limiting.
3285
3286 If unsure, say N.
3287
3288config INT_POW_KUNIT_TEST
3289 tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS
3290 depends on KUNIT
3291 default KUNIT_ALL_TESTS
3292 help
3293 This option enables the KUnit test suite for the int_pow function,
3294 which performs integer exponentiation. The test suite is designed to
3295 verify that the implementation of int_pow correctly computes the power
3296 of a given base raised to a given exponent.
3297
3298 Enabling this option will include tests that check various scenarios
3299 and edge cases to ensure the accuracy and reliability of the exponentiation
3300 function.
3301
3302 If unsure, say N
3303
3304config INT_SQRT_KUNIT_TEST
3305 tristate "Integer square root test" if !KUNIT_ALL_TESTS
3306 depends on KUNIT
3307 default KUNIT_ALL_TESTS
3308 help
3309 This option enables the KUnit test suite for the int_sqrt() function,
3310 which performs square root calculation. The test suite checks
3311 various scenarios, including edge cases, to ensure correctness.
3312
3313 Enabling this option will include tests that check various scenarios
3314 and edge cases to ensure the accuracy and reliability of the square root
3315 function.
3316
3317 If unsure, say N
3318
3319config INT_LOG_KUNIT_TEST
3320 tristate "Integer log (int_log) test" if !KUNIT_ALL_TESTS
3321 depends on KUNIT
3322 default KUNIT_ALL_TESTS
3323 help
3324 This option enables the KUnit test suite for the int_log library, which
3325 provides two functions to compute the integer logarithm in base 2 and
3326 base 10, called respectively as intlog2 and intlog10.
3327
3328 If unsure, say N
3329
3330config GCD_KUNIT_TEST
3331 tristate "Greatest common divisor test" if !KUNIT_ALL_TESTS
3332 depends on KUNIT
3333 default KUNIT_ALL_TESTS
3334 help
3335 This option enables the KUnit test suite for the gcd() function,
3336 which computes the greatest common divisor of two numbers.
3337
3338 This test suite verifies the correctness of gcd() across various
3339 scenarios, including edge cases.
3340
3341 If unsure, say N
3342
3343config PRIME_NUMBERS_KUNIT_TEST
3344 tristate "Prime number generator test" if !KUNIT_ALL_TESTS
3345 depends on KUNIT
3346 depends on PRIME_NUMBERS
3347 default KUNIT_ALL_TESTS
3348 help
3349 This option enables the KUnit test suite for the {is,next}_prime_number
3350 functions.
3351
3352 Enabling this option will include tests that compare the prime number
3353 generator functions against a brute force implementation.
3354
3355 If unsure, say N
3356
3357endif # RUNTIME_TESTING_MENU
3358
3359config ARCH_USE_MEMTEST
3360 bool
3361 help
3362 An architecture should select this when it uses early_memtest()
3363 during boot process.
3364
3365config MEMTEST
3366 bool "Memtest"
3367 depends on ARCH_USE_MEMTEST
3368 help
3369 This option adds a kernel parameter 'memtest', which allows memtest
3370 to be set and executed.
3371 memtest=0, mean disabled; -- default
3372 memtest=1, mean do 1 test pattern;
3373 ...
3374 memtest=17, mean do 17 test patterns.
3375 If you are unsure how to answer this question, answer N.
3376
3377
3378
3379config HYPERV_TESTING
3380 bool "Microsoft Hyper-V driver testing"
3381 default n
3382 depends on HYPERV && DEBUG_FS
3383 help
3384 Select this option to enable Hyper-V vmbus testing.
3385
3386endmenu # "Kernel Testing and Coverage"
3387
3388menu "Rust hacking"
3389
3390config RUST_DEBUG_ASSERTIONS
3391 bool "Debug assertions"
3392 depends on RUST
3393 help
3394 Enables rustc's `-Cdebug-assertions` codegen option.
3395
3396 This flag lets you turn `cfg(debug_assertions)` conditional
3397 compilation on or off. This can be used to enable extra debugging
3398 code in development but not in production. For example, it controls
3399 the behavior of the standard library's `debug_assert!` macro.
3400
3401 Note that this will apply to all Rust code, including `core`.
3402
3403 If unsure, say N.
3404
3405config RUST_OVERFLOW_CHECKS
3406 bool "Overflow checks"
3407 default y
3408 depends on RUST
3409 help
3410 Enables rustc's `-Coverflow-checks` codegen option.
3411
3412 This flag allows you to control the behavior of runtime integer
3413 overflow. When overflow-checks are enabled, a Rust panic will occur
3414 on overflow.
3415
3416 Note that this will apply to all Rust code, including `core`.
3417
3418 If unsure, say Y.
3419
3420config RUST_BUILD_ASSERT_ALLOW
3421 bool "Allow unoptimized build-time assertions"
3422 depends on RUST
3423 help
3424 Controls how `build_error!` and `build_assert!` are handled during the build.
3425
3426 If calls to them exist in the binary, it may indicate a violated invariant
3427 or that the optimizer failed to verify the invariant during compilation.
3428
3429 This should not happen, thus by default the build is aborted. However,
3430 as an escape hatch, you can choose Y here to ignore them during build
3431 and let the check be carried at runtime (with `panic!` being called if
3432 the check fails).
3433
3434 If unsure, say N.
3435
3436config RUST_KERNEL_DOCTESTS
3437 bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
3438 depends on RUST && KUNIT=y
3439 default KUNIT_ALL_TESTS
3440 help
3441 This builds the documentation tests of the `kernel` crate
3442 as KUnit tests.
3443
3444 For more information on KUnit and unit tests in general,
3445 please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
3446
3447 If unsure, say N.
3448
3449endmenu # "Rust"
3450
3451endmenu # Kernel hacking