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Filename Latest commit message Latest commit date
Tony Jones 8bf8c6da53 perf script: Fix crash when processing recorded stat data
While updating perf to work with Python3 and Python2 I noticed that the
stat-cpi script was dumping core.

$ perf  stat -e cycles,instructions record -o /tmp/perf.data /bin/false

 Performance counter stats for '/bin/false':

           802,148      cycles

           604,622      instructions                                                       802,148      cycles
           604,622      instructions

       0.001445842 seconds time elapsed

$ perf script -i /tmp/perf.data -s scripts/python/stat-cpi.py
Segmentation fault (core dumped)
...
...
    rblist=rblist@entry=0xb2a200 <rt_stat>,
    new_entry=new_entry@entry=0x7ffcb755c310) at util/rblist.c:33
    ctx=<optimized out>, type=<optimized out>, create=<optimized out>,
    cpu=<optimized out>, evsel=<optimized out>) at util/stat-shadow.c:118
    ctx=<optimized out>, type=<optimized out>, st=<optimized out>)
    at util/stat-shadow.c:196
    count=count@entry=727442, cpu=cpu@entry=0, st=0xb2a200 <rt_stat>)
    at util/stat-shadow.c:239
    config=config@entry=0xafeb40 <stat_config>,
    counter=counter@entry=0x133c6e0) at util/stat.c:372
...
...

The issue is that since 1fcd03946b perf_stat__update_shadow_stats now calls
update_runtime_stat passing rt_stat rather than calling update_stats but
perf_stat__init_shadow_stats has never been called to initialize rt_stat in
the script path processing recorded stat data.

Since I can't see any reason why perf_stat__init_shadow_stats() is presently
initialized like it is in builtin-script.c::perf_sample__fprint_metric()
[4bd1bef8bb] I'm proposing it instead be initialized once in __cmd_script

Committer testing:

After applying the patch:

  # perf script -i /tmp/perf.data -s tools/perf/scripts/python/stat-cpi.py
       0.001970: cpu -1, thread -1 -> cpi 1.709079 (1075684/629394)
  #

No segfault.

Signed-off-by: Tony Jones <tonyj@suse.de>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Fixes: 1fcd03946b ("perf stat: Update per-thread shadow stats")
Link: http://lkml.kernel.org/r/20190120191414.12925-1-tonyj@suse.de
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-01-21 11:29:07 -03:00
arch arch: restore generic-y += shmparam.h for some architectures 2019-01-06 18:16:11 -08:00
block for-4.21/block-20190102 2019-01-02 18:49:58 -08:00
certs kbuild: remove redundant target cleaning on failure 2019-01-06 09:46:51 +09:00
crypto
Documentation Kbuild late updates for v4.21 2019-01-06 16:33:10 -08:00
drivers chrome platform changes for v4.21 2019-01-06 11:40:06 -08:00
firmware kbuild: change filechk to surround the given command with { } 2019-01-06 09:46:51 +09:00
fs Add Adiantum support for fscrypt 2019-01-06 12:21:11 -08:00
include Kbuild late updates for v4.21 2019-01-06 16:33:10 -08:00
init jump_label: move 'asm goto' support test to Kconfig 2019-01-06 09:46:51 +09:00
ipc
kernel perf core: Fix perf_proc_update_handler() bug 2019-01-18 11:10:38 -03:00
lib Kbuild late updates for v4.21 2019-01-06 16:33:10 -08:00
LICENSES
mm Change mincore() to count "mapped" pages rather than "cached" pages 2019-01-06 13:43:02 -08:00
net jump_label: move 'asm goto' support test to Kconfig 2019-01-06 09:46:51 +09:00
samples Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid 2019-01-05 17:53:40 -08:00
scripts kconfig: rename generated .*conf-cfg to *conf-cfg 2019-01-06 10:47:09 +09:00
security Merge branch 'mount.part1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-01-05 13:25:58 -08:00
sound Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
tools perf script: Fix crash when processing recorded stat data 2019-01-21 11:29:07 -03:00
usr
virt Merge branch 'akpm' (patches from Andrew) 2019-01-05 09:16:18 -08:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap A few early MIPS fixes for 4.21: 2019-01-05 12:48:25 -08:00
COPYING
CREDITS Add CREDITS entry for Shaohua Li 2019-01-04 14:27:09 -07:00
Kbuild kbuild: use assignment instead of define ... endef for filechk_* rules 2019-01-06 10:22:35 +09:00
Kconfig
MAINTAINERS chrome platform changes for v4.21 2019-01-06 11:40:06 -08:00
Makefile Linux 5.0-rc1 2019-01-06 17:08:20 -08:00
README

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.