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  1. 03 Aug, 2016 1 commit
    • Arnaldo Carvalho de Melo's avatar
      perf tests bpf: Use SyS_epoll_wait alias · c369e0a1
      Arnaldo Carvalho de Melo authored 
      Something made the sys_epoll_wait() function alias not to be found in
the vmlinux DWARF info, being found only in /proc/kallsyms, which made
the BPF perf tests to fail:

  [root@jouet ~]# perf test BPF
  37: Test BPF filter                                          :
  37.1: Test basic BPF filtering                               : FAILED!
  37.2: Test BPF prologue generation                           : Skip
  37.3: Test BPF relocation checker                            : Skip
  [root@jouet ~]#

Using -v we can see it is failing to find DWARF info for the probed function,
sys_epoll_wait, which we can find in /proc/kallsyms but not in vmlinux with
CONFIG_DEBUG_INFO:

  [root@jouet ~]# grep -w sys_epoll_wait /proc/kallsyms
  ffffffffbd295b50 T sys_epoll_wait
  [root@jouet ~]#

  [root@jouet ~]# readelf -wi /lib/modules/4.7.0+/build/vmlinux | grep -w sys_epoll_wait
  [root@jouet ~]#

If we try to use perf probe:

[root@jouet ~]# perf probe sys_epoll_wait
Failed to find debug information for address ffffffffbd295b50
Probe point 'sys_epoll_wait' not found.
  Error: Failed to add events.
[root@jouet ~]#

It all works if we use SyS_epoll_wait, that is just an alias to the probed
function:

  [root@jouet ~]# grep -i sys_epoll_wait /proc/kallsyms
  ffffffffbd295b50 T SyS_epoll_wait
  ffffffffbd295b50 T sys_epoll_wait
  [root@jouet ~]#

So use it:

  [root@jouet ~]# perf test BPF
  37: Test BPF filter                                          :
  37.1: Test basic BPF filtering                               : Ok
  37.2: Test BPF prologue generation                           : Ok
  37.3: Test BPF relocation checker                            : Ok
  [root@jouet ~]#

Further info:

  [root@jouet ~]# gcc --version
  gcc (GCC) 6.1.1 20160621 (Red Hat 6.1.1-3)
  [acme@jouet linux]$ cat /etc/fedora-release
  Fedora release 24 (Twenty Four)

Investigation as to why it fails is still underway, but it was always
going from sys_epoll_wait to SyS_epoll_wait when looking up the DWARF
info in vmlinux, and this is what is breaking now.

Switching to use SyS_epoll_wait allows this test to proceed and test the
BPF code it was designed for, so lets have this in to allow passing this
test while we fix the root cause.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-7hekjp0bodwjbb419sl2b55h@git.kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      c369e0a1
  3. 02 Aug, 2016 10 commits
  5. 01 Aug, 2016 3 commits
  7. 29 Jul, 2016 2 commits
  9. 28 Jul, 2016 1 commit
  11. 25 Jul, 2016 3 commits
  13. 22 Jul, 2016 5 commits
  15. 21 Jul, 2016 3 commits
  17. 20 Jul, 2016 1 commit
  19. 19 Jul, 2016 1 commit
    • Ingo Molnar's avatar
      Merge tag 'perf-core-for-mingo-20160718' of... · 5048c2af
      Ingo Molnar authored 
      Merge tag 'perf-core-for-mingo-20160718' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

 - Properly report when a function wildcard produces no matches in 'perf probe'
   (Masami Hiramatsu)

 - Balance opening and reading events in 'perf stat', which could cause
   it to get stuck trying to close invalid file descriptors (Mark Rutland)

Infrastructure changes:

 - Copy more headers from the kernel, this time for headers that
   were just including the contents of its kernel counterparts, should
   help resolving the problems with linux-next, where some uapi related
   patches seem to be breaking tools/object/ build. (Arnaldo Carvalho de Melo)

   Some more combing will be done, but at least it is possible to build
   perf out of tree, via a detached tarball (make help | grep perf),
   without including kernel files in its MANIFEST (Arnaldo Carvalho de Melo)

 - Fix smatch found errors that were not causing problems, but are
   mistakes nonetheless (Dan Carpenter)

 - Fix string vs. byte array resolving in the python script code (Jiri Olsa)
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      5048c2af
  21. 18 Jul, 2016 10 commits
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