tjh.dev
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1444015
3
928
Clone this repository
https://tangled.org/tjh.dev/kernel
https://tangled.org/did:plc:65gha4t3avpfpzmvpbwovss7/kernel
git@gordian.tjh.dev:tjh.dev/kernel
git@gordian.tjh.dev:did:plc:65gha4t3avpfpzmvpbwovss7/kernel
For self-hosted knots, clone URLs may differ based on your setup.
Download tar.gz
Pull ARM fixes from Russell King:
- avoid unnecessary rebuilds for library objects
- fix return value of __setup handlers
- fix invalid input check for "crashkernel=" kernel option
- silence KASAN warnings in unwind_frame
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 9191/1: arm/stacktrace, kasan: Silence KASAN warnings in unwind_frame()
ARM: 9190/1: kdump: add invalid input check for 'crashkernel=0'
ARM: 9187/1: JIVE: fix return value of __setup handler
ARM: 9189/1: decompressor: fix unneeded rebuilds of library objects
Pull more perf tools updates from Arnaldo Carvalho de Melo:
- Avoid SEGV if core.cpus isn't set in 'perf stat'.
- Stop depending on .git files for building PERF-VERSION-FILE, used in
'perf --version', fixing some perf tools build scenarios.
- Convert tracepoint.py example to python3.
- Update UAPI header copies from the kernel sources: socket,
mman-common, msr-index, KVM, i915 and cpufeatures.
- Update copy of libbpf's hashmap.c.
- Directly return instead of using local ret variable in
evlist__create_syswide_maps(), found by coccinelle.
* tag 'perf-tools-for-v5.18-2022-04-02' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
perf python: Convert tracepoint.py example to python3
perf evlist: Directly return instead of using local ret variable
perf cpumap: More cpu map reuse by merge.
perf cpumap: Add is_subset function
perf evlist: Rename cpus to user_requested_cpus
perf tools: Stop depending on .git files for building PERF-VERSION-FILE
tools headers cpufeatures: Sync with the kernel sources
tools headers UAPI: Sync drm/i915_drm.h with the kernel sources
tools headers UAPI: Sync linux/kvm.h with the kernel sources
tools kvm headers arm64: Update KVM headers from the kernel sources
tools arch x86: Sync the msr-index.h copy with the kernel sources
tools headers UAPI: Sync asm-generic/mman-common.h with the kernel
perf beauty: Update copy of linux/socket.h with the kernel sources
perf tools: Update copy of libbpf's hashmap.c
perf stat: Avoid SEGV if core.cpus isn't set
Pull Kbuild fixes from Masahiro Yamada:
- Fix empty $(PYTHON) expansion.
- Fix UML, which got broken by the attempt to suppress Clang warnings.
- Fix warning message in modpost.
* tag 'kbuild-fixes-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
modpost: restore the warning message for missing symbol versions
Revert "um: clang: Strip out -mno-global-merge from USER_CFLAGS"
kbuild: Remove '-mno-global-merge'
kbuild: fix empty ${PYTHON} in scripts/link-vmlinux.sh
kconfig: remove stale comment about removed kconfig_print_symbol()
Convert the tracepoint.py file to python3 as many of the files in
tools/perf are already written in python3.
Committer testing:
# export PYTHONPATH=/tmp/build/perf/python/
# python3 ~acme/git/perf/tools/perf/python/tracepoint.py | head
time 67394457376909 prev_comm=swapper/12 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=gnome-terminal- next_pid=3313 next_prio=120
time 67394457807669 prev_comm=python3 prev_pid=1485930 prev_prio=120 prev_state=0x1 ==> next_comm=swapper/13 next_pid=0 next_prio=120
time 67394457811859 prev_comm=swapper/13 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=python3 next_pid=1485930 next_prio=120
time 67394457824929 prev_comm=python3 prev_pid=1485930 prev_prio=120 prev_state=0x1 ==> next_comm=swapper/13 next_pid=0 next_prio=120
time 67394457831899 prev_comm=swapper/13 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=python3 next_pid=1485930 next_prio=120
time 67394457842299 prev_comm=python3 prev_pid=1485930 prev_prio=120 prev_state=0x1 ==> next_comm=swapper/13 next_pid=0 next_prio=120
time 67394457844179 prev_comm=swapper/13 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=python3 next_pid=1485930 next_prio=120
time 67394457853879 prev_comm=python3 prev_pid=1485930 prev_prio=120 prev_state=0x1 ==> next_comm=swapper/13 next_pid=0 next_prio=120
time 67394457856339 prev_comm=swapper/13 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=python3 next_pid=1485930 next_prio=120
time 67394457865659 prev_comm=python3 prev_pid=1485930 prev_prio=120 prev_state=0x1 ==> next_comm=swapper/13 next_pid=0 next_prio=120
Traceback (most recent call last):
File "/var/home/acme/git/perf/tools/perf/python/tracepoint.py", line 48, in <module>
main()
File "/var/home/acme/git/perf/tools/perf/python/tracepoint.py", line 37, in main
print("time %u prev_comm=%s prev_pid=%d prev_prio=%d prev_state=0x%x ==> next_comm=%s next_pid=%d next_prio=%d" % (
BrokenPipeError: [Errno 32] Broken pipe
#
Signed-off-by: Tanu M <tanu235m@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/linux-perf-users/CAPS78prawYzRZnyhWjgOnGw4EwoswNwztvfZFdCOPOydFzVwzQ@mail.gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The following KASAN warning is detected by QEMU.
==================================================================
BUG: KASAN: stack-out-of-bounds in unwind_frame+0x508/0x870
Read of size 4 at addr c36bba90 by task cat/163
CPU: 1 PID: 163 Comm: cat Not tainted 5.10.0-rc1 #40
Hardware name: ARM-Versatile Express
[<c0113fac>] (unwind_backtrace) from [<c010e71c>] (show_stack+0x10/0x14)
[<c010e71c>] (show_stack) from [<c0b805b4>] (dump_stack+0x98/0xb0)
[<c0b805b4>] (dump_stack) from [<c0b7d658>] (print_address_description.constprop.0+0x58/0x4bc)
[<c0b7d658>] (print_address_description.constprop.0) from [<c031435c>] (kasan_report+0x154/0x170)
[<c031435c>] (kasan_report) from [<c0113c44>] (unwind_frame+0x508/0x870)
[<c0113c44>] (unwind_frame) from [<c010e298>] (__save_stack_trace+0x110/0x134)
[<c010e298>] (__save_stack_trace) from [<c01ce0d8>] (stack_trace_save+0x8c/0xb4)
[<c01ce0d8>] (stack_trace_save) from [<c0313520>] (kasan_set_track+0x38/0x60)
[<c0313520>] (kasan_set_track) from [<c0314cb8>] (kasan_set_free_info+0x20/0x2c)
[<c0314cb8>] (kasan_set_free_info) from [<c0313474>] (__kasan_slab_free+0xec/0x120)
[<c0313474>] (__kasan_slab_free) from [<c0311e20>] (kmem_cache_free+0x7c/0x334)
[<c0311e20>] (kmem_cache_free) from [<c01c35dc>] (rcu_core+0x390/0xccc)
[<c01c35dc>] (rcu_core) from [<c01013a8>] (__do_softirq+0x180/0x518)
[<c01013a8>] (__do_softirq) from [<c0135214>] (irq_exit+0x9c/0xe0)
[<c0135214>] (irq_exit) from [<c01a40e4>] (__handle_domain_irq+0xb0/0x110)
[<c01a40e4>] (__handle_domain_irq) from [<c0691248>] (gic_handle_irq+0xa0/0xb8)
[<c0691248>] (gic_handle_irq) from [<c0100b0c>] (__irq_svc+0x6c/0x94)
Exception stack(0xc36bb928 to 0xc36bb970)
b920: c36bb9c0 00000000 c0126919 c0101228 c36bb9c0 b76d7730
b940: c36b8000 c36bb9a0 c3335b00 c01ce0d8 00000003 c36bba3c c36bb940 c36bb978
b960: c010e298 c011373c 60000013 ffffffff
[<c0100b0c>] (__irq_svc) from [<c011373c>] (unwind_frame+0x0/0x870)
[<c011373c>] (unwind_frame) from [<00000000>] (0x0)
The buggy address belongs to the page:
page:(ptrval) refcount:0 mapcount:0 mapping:00000000 index:0x0 pfn:0x636bb
flags: 0x0()
raw: 00000000 00000000 ef867764 00000000 00000000 00000000 ffffffff 00000000
page dumped because: kasan: bad access detected
addr c36bba90 is located in stack of task cat/163 at offset 48 in frame:
stack_trace_save+0x0/0xb4
this frame has 1 object:
[32, 48) 'trace'
Memory state around the buggy address:
c36bb980: f1 f1 f1 f1 00 04 f2 f2 00 00 f3 f3 00 00 00 00
c36bba00: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
>c36bba80: 00 00 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
^
c36bbb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
c36bbb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
There is a same issue on x86 and has been resolved by the commit f7d27c35ddff
("x86/mm, kasan: Silence KASAN warnings in get_wchan()").
The solution could be applied to arm architecture too.
Signed-off-by: Lin Yujun <linyujun809@huawei.com>
Reported-by: He Ying <heying24@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Since commit 251cc826be7d ("ARM: 9154/1: decompressor: do not copy source
files while building"), the following three are rebuilt every time.
AS arch/arm/boot/compressed/lib1funcs.o
AS arch/arm/boot/compressed/ashldi3.o
AS arch/arm/boot/compressed/bswapsdi2.o
Move the "OBJS += ..." line up so these objects are added to 'targets'.
Fixes: 251cc826be7d ("ARM: 9154/1: decompressor: do not copy source files while building")
Reported-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Pull MIPS fixes from Thomas Bogendoerfer:
- build fix for gpio
- fix crc32 build problems
- check for failed memory allocations
* tag 'mips_5.18_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
MIPS: crypto: Fix CRC32 code
MIPS: rb532: move GPIOD definition into C-files
MIPS: lantiq: check the return value of kzalloc()
mips: sgi-ip22: add a check for the return of kzalloc()
This log message was accidentally chopped off.
I was wondering why this happened, but checking the ML log, Mark
precisely followed my suggestion [1].
I just used "..." because I was too lazy to type the sentence fully.
Sorry for the confusion.
[1]: https://lore.kernel.org/all/CAK7LNAR6bXXk9-ZzZYpTqzFqdYbQsZHmiWspu27rtsFxvfRuVA@mail.gmail.com/
Fixes: 4a6795933a89 ("kbuild: modpost: Explicitly warn about unprototyped symbols")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Addresses this coccinelle warning:
./tools/perf/util/evlist.c:1333:5-8: Unneeded variable: "err". Return
"- ENOMEM" on line 1358
Signed-off-by: Haowen Bai <baihaowen@meizu.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/1648432532-23151-1-git-send-email-baihaowen@meizu.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add invalid input check expression when 'crashkernel=0' is specified
running kdump.
Signed-off-by: Austin Kim <austindh.kim@gmail.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
The -nostdlib option requests the compiler to not use the standard
system startup files or libraries when linking. It is effective only
when $(CC) is used as a linker driver.
Since commit fe00e50b2db8 ("ARM: 8858/1: vdso: use $(LD) instead of
$(CC) to link VDSO"), $(LD) is directly used, hence -nostdlib is
unneeded.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Pull kvm fixes from Paolo Bonzini:
- Only do MSR filtering for MSRs accessed by rdmsr/wrmsr
- Documentation improvements
- Prevent module exit until all VMs are freed
- PMU Virtualization fixes
- Fix for kvm_irq_delivery_to_apic_fast() NULL-pointer dereferences
- Other miscellaneous bugfixes
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (42 commits)
KVM: x86: fix sending PV IPI
KVM: x86/mmu: do compare-and-exchange of gPTE via the user address
KVM: x86: Remove redundant vm_entry_controls_clearbit() call
KVM: x86: cleanup enter_rmode()
KVM: x86: SVM: fix tsc scaling when the host doesn't support it
kvm: x86: SVM: remove unused defines
KVM: x86: SVM: move tsc ratio definitions to svm.h
KVM: x86: SVM: fix avic spec based definitions again
KVM: MIPS: remove reference to trap&emulate virtualization
KVM: x86: document limitations of MSR filtering
KVM: x86: Only do MSR filtering when access MSR by rdmsr/wrmsr
KVM: x86/emulator: Emulate RDPID only if it is enabled in guest
KVM: x86/pmu: Fix and isolate TSX-specific performance event logic
KVM: x86: mmu: trace kvm_mmu_set_spte after the new SPTE was set
KVM: x86/svm: Clear reserved bits written to PerfEvtSeln MSRs
KVM: x86: Trace all APICv inhibit changes and capture overall status
KVM: x86: Add wrappers for setting/clearing APICv inhibits
KVM: x86: Make APICv inhibit reasons an enum and cleanup naming
KVM: X86: Handle implicit supervisor access with SMAP
KVM: X86: Rename variable smap to not_smap in permission_fault()
...
README