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Filename Latest commit message Latest commit date
Jiri Olsa 3f938ee2f6 perf machine: Fix segfault for kernel.kptr_restrict=2
Michael reported the segfault when kernel.kptr_restrict=2 is set.

  $ perf record ls
  ...
  perf: Segmentation fault
  Obtained 16 stack frames.
  ./perf(dump_stack+0x2d) [0x5068df]
  ./perf(sighandler_dump_stack+0x2d) [0x5069bf]
  ./perf() [0x43e47b]
  /lib64/libc.so.6(+0x3594f) [0x7f762004794f]
  /lib64/libc.so.6(strlen+0x26) [0x7f762009ef86]
  /lib64/libc.so.6(__strdup+0xd) [0x7f762009ecbd]
  ./perf(maps__set_kallsyms_ref_reloc_sym+0x4d) [0x51590f]
  ./perf(machine__create_kernel_maps+0x136) [0x50a7de]
  ./perf(perf_session__create_kernel_maps+0x2c) [0x510a81]
  ./perf(perf_session__new+0x13d) [0x510e23]
  ./perf() [0x43fd61]
  ./perf(cmd_record+0x704) [0x441823]
  ./perf() [0x4bc1a0]
  ./perf() [0x4bc40d]
  ./perf() [0x4bc55f]
  ./perf(main+0x2d5) [0x4bc939]
  Segmentation fault (core dumped)

The reason is that with kernel.kptr_restrict=2, we don't get
the symbol from machine__get_running_kernel_start, which we
want to use in maps__set_kallsyms_ref_reloc_sym and we crash.

Check the symbol name value before calling
maps__set_kallsyms_ref_reloc_sym() and succeed without ref_reloc_sym
being set. It's safe because we check its existence before we use it.

Reported-by: Michael Petlan <mpetlan@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20170626095153.553-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2017-06-26 11:52:37 -03:00
arch perf/x86/intel: Add 1G DTLB load/store miss support for SKL 2017-06-22 11:07:08 +02:00
block
certs
crypto
Documentation One build fix for an Amlogic clk driver and a handful of Allwinner clk driver 2017-06-20 11:02:29 +08:00
drivers One build fix for an Amlogic clk driver and a handful of Allwinner clk driver 2017-06-20 11:02:29 +08:00
firmware
fs mm: larger stack guard gap, between vmas 2017-06-19 21:50:20 +08:00
include One build fix for an Amlogic clk driver and a handful of Allwinner clk driver 2017-06-20 11:02:29 +08:00
init
ipc
kernel perf/aux: Correct return code of rb_alloc_aux() if !has_aux(ev) 2017-06-21 11:58:30 +02:00
lib
mm mm: larger stack guard gap, between vmas 2017-06-19 21:50:20 +08:00
net
samples
scripts
security
sound
tools perf machine: Fix segfault for kernel.kptr_restrict=2 2017-06-26 11:52:37 -03:00
usr
virt
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 4.12-rc6 2017-06-19 22:19:37 +08:00
README

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.