tjh.dev
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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
Arnaldo reported broken builds in some distros using a newer flex
release, 2.6.4, found in Alpine Linux 3.6 and Edge, with flex not
spotting the REJECT macro:
CC /tmp/build/perf/util/parse-events-flex.o
util/parse-events.l: In function 'parse_events_lex':
/tmp/build/perf/util/parse-events-flex.c:4734:16: error: \
'reject_used_but_not_detected' undeclared (first use in this function)
It's happening because we put the REJECT under another USER_REJECT macro
in following commit:
9445464bb831 perf tools: Unwind properly location after REJECT
Fortunately flex provides option for force it to use REJECT, adding it
to parse-events.l.
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Andi Kleen <andi@firstfloor.org>
Tested-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Fixes: 9445464bb831 ("perf tools: Unwind properly location after REJECT")
Link: http://lkml.kernel.org/n/tip-7kdont984mw12ijk7rji6b8p@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
After the SPDX license tags were added a number of tooling headers got out of
sync with their kernel variants, generating lots of build warnings.
Sync them:
- tools/arch/x86/include/asm/disabled-features.h,
tools/arch/x86/include/asm/required-features.h,
tools/include/linux/hash.h:
Remove the SPDX tag where the kernel version does not have it.
- tools/include/asm-generic/bitops/__fls.h,
tools/include/asm-generic/bitops/arch_hweight.h,
tools/include/asm-generic/bitops/const_hweight.h,
tools/include/asm-generic/bitops/fls.h,
tools/include/asm-generic/bitops/fls64.h,
tools/include/uapi/asm-generic/ioctls.h,
tools/include/uapi/asm-generic/mman-common.h,
tools/include/uapi/sound/asound.h,
tools/include/uapi/linux/kvm.h,
tools/include/uapi/linux/perf_event.h,
tools/include/uapi/linux/sched.h,
tools/include/uapi/linux/vhost.h,
tools/include/uapi/sound/asound.h:
Add the SPDX tag of the respective kernel header.
- tools/include/uapi/linux/bpf_common.h,
tools/include/uapi/linux/fcntl.h,
tools/include/uapi/linux/hw_breakpoint.h,
tools/include/uapi/linux/mman.h,
tools/include/uapi/linux/stat.h,
Change the tag to the kernel header version:
-/* SPDX-License-Identifier: GPL-2.0 */
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
Also sync other header details:
- include/uapi/sound/asound.h:
Fix pointless end of line whitespace noise the header grew in this cycle.
- tools/arch/x86/lib/memcpy_64.S:
Sync the code and add tools/include/asm/export.h with dummy wrappers
to support building the kernel side code in a tooling header environment.
- tools/include/uapi/asm-generic/mman.h,
tools/include/uapi/linux/bpf.h:
Sync other details that don't impact tooling's use of the ABIs.
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The following commit:
864c2357ca89 ("perf/core: Do not set cpuctx->cgrp for unscheduled cgroups")
made list_update_cgroup_event() skip setting cpuctx->cgrp if no cgroup event
targets %current's cgroup.
This breaks perf_event's hierarchical support because events which target one
of the ancestors get ignored.
Fix it by using cgroup_is_descendant() test instead of equality.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@fb.com
Cc: stable@vger.kernel.org # v4.9+
Fixes: 864c2357ca89 ("perf/core: Do not set cpuctx->cgrp for unscheduled cgroups")
Link: http://lkml.kernel.org/r/20171028164237.GA972780@devbig577.frc2.facebook.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For some odd historical reason, we preprocessed the linker scripts with
"-C", which keeps comments around. That makes no sense, since the
comments are not meaningful for the build anyway.
And it actually breaks things, since linker scripts can't have C++ style
"//" comments in them, so keeping comments after preprocessing now
limits us in odd and surprising ways in our header files for no good
reason.
The -C option goes back to pre-git and pre-bitkeeper times, but seems to
have been historically used (along with "-traditional") for some
odd-ball architectures (ia64, MIPS and SH). It probably didn't matter
back then either, but might possibly have been used to minimize the
difference between the original file and the pre-processed result.
The reason for this may be lost in time, but let's not perpetuate it
only because we can't remember why we did this crazy thing.
This was triggered by the recent addition of SPDX lines to the source
tree, where people apparently were confused about why header files
couldn't use the C++ comment format.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull perf/urgent fixes from Arnaldo Carvalho de Melo:
- Fix memory corruption in the annotation routines because of zero
length symbols (asm ones) (Ravi Bangoria)
- Fix printing garbage as an error message when re-running the
lexer events matcher (Jiri Olsa)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This reverts commit 51204e0639c49ada02fd823782ad673b6326d748.
There wasn't really any good reason for it, and people are complaining
(rightly) that it broke existing practice.
Cc: Len Brown <len.brown@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull xen fixes from Juergen Gross:
- a fix for the Xen gntdev device repairing an issue in case of partial
failure of mapping multiple pages of another domain
- a fix of a regression in the Xen balloon driver introduced in 4.13
- a build fix for Xen on ARM which will trigger e.g. for Linux RT
- a maintainers update for pvops (not really Xen, but carrying through
this tree just for convenience)
* tag 'for-linus-4.14c-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
maintainers: drop Chris Wright from pvops
arm/xen: don't inclide rwlock.h directly.
xen: fix booting ballooned down hvm guest
xen/gntdev: avoid out of bounds access in case of partial gntdev_mmap()
We have defined YY_USER_ACTION to keep trace of the column location
during events parsing, but we need to clean it up when we call REJECT.
When REJECT is called, the lexer shrinks the text and re-runs the
matching, so we need to address it in resuming the previous location
value to keep it correct for error display, like:
Before:
$ perf stat -e 'cpu/uops_executed.core,krava/' true
event syntax error: '..38;5;9:mi=01;05;37;41:su=48;5;196;38;5;15:sg=48;5;1\
1;38;5;16:ca=48;5;196;38;5;226:tw=48;5;10;38;5;16:ow=48;5;10;38;5;21:st=48;5;\
21;38;50
�'
\___ unknown term
After:
$ ./perf stat -e 'cpu/uops_executed.core,krava/' true
event syntax error: '..cuted.core,krava/'
\___ unknown term
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Andi Kleen <ak@linux.intel.com>
Cc: Changbin Du <changbin.du@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-vug2hchlny30jfsfrumbym26@git.kernel.org
Link: http://lkml.kernel.org/r/20171009140944.GD28623@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull arm64 fix from Catalin Marinas:
"Check addr_limit in arm64 __dump_instr()"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: ensure __dump_instr() checks addr_limit
Pull ARC fixes from Vineet Gupta:
- Fixes for HSDK platform
- module build error for !LLSC config
* tag 'arc-4.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
ARC: unbork module link errors with !CONFIG_ARC_HAS_LLSC
ARC: [plat-hsdk] Increase SDIO CIU frequency to 50000000Hz
ARC: [plat-hsdk] select CONFIG_RESET_HSDK from Kconfig
Mails to chrisw@sous-sol.org are not deliverable since several months.
Drop him as PARAVIRT_OPS maintainer.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Chris Wright <chrisw@redhat.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Perf top is often crashing at very random locations on powerpc. After
investigating, I found the crash only happens when sample is of zero
length symbol. Powerpc kernel has many such symbols which does not
contain length details in vmlinux binary and thus start and end
addresses of such symbols are same.
Structure
struct sym_hist {
u64 nr_samples;
u64 period;
struct sym_hist_entry addr[0];
};
has last member 'addr[]' of size zero. 'addr[]' is an array of addresses
that belongs to one symbol (function). If function consist of 100
instructions, 'addr' points to an array of 100 'struct sym_hist_entry'
elements. For zero length symbol, it points to the *empty* array, i.e.
no members in the array and thus offset 0 is also invalid for such
array.
static int __symbol__inc_addr_samples(...)
{
...
offset = addr - sym->start;
h = annotation__histogram(notes, evidx);
h->nr_samples++;
h->addr[offset].nr_samples++;
h->period += sample->period;
h->addr[offset].period += sample->period;
...
}
Here, when 'addr' is same as 'sym->start', 'offset' becomes 0, which is
valid for normal symbols but *invalid* for zero length symbols and thus
updating h->addr[offset] causes memory corruption.
Fix this by adding one dummy element for zero length symbols.
Link: https://lkml.org/lkml/2016/10/10/148
Fixes: edee44be5919 ("perf annotate: Don't throw error for zero length symbols")
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Kim Phillips <kim.phillips@arm.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Taeung Song <treeze.taeung@gmail.com>
Link: http://lkml.kernel.org/r/1508854806-10542-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
README