lkml.org 
[lkml]   [2015]   [Sep]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH] perf tools: Fix segfault in 'perf top'
On Fri, Sep 11, 2015 at 04:59:11AM +0000, Wang Nan wrote:
> 'perf top' segfaults with following operation:
>
> # perf top -e page-faults -p 15173 # 15173 never generate page-fault
>
> Then on the resulting empty interface, press right key:
>
> # ./perf top -e page-faults -p 11400
> perf: Segmentation fault
> -------- backtrace --------
> ./perf[0x535428]
> /lib64/libc.so.6(+0x3545f)[0x7f0dd360745f]
> ./perf[0x531d46]
> ./perf(perf_evlist__tui_browse_hists+0x96)[0x5340d6]
> ./perf[0x44ba2f]
> /lib64/libpthread.so.0(+0x81d0)[0x7f0dd49dc1d0]
> /lib64/libc.so.6(clone+0x6c)[0x7f0dd36b90dc]
>
> The bug reside in perf_evsel__hists_browse() that, in the above circumstance
> browser->selection can be NULL, but code after skip_annotation doesn't consider
> it.
>
> This patch fix it by checing browser->selection before fetching
> browser->selection->map and browser->selection->sym.

I'm ok with this change, just a nitpick below..


>
> Signed-off-by: Wang Nan <wangnan0@huawei.com>
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Cc: Namhyung Kim <namhyung@kernel.org>
> ---
> tools/perf/ui/browsers/hists.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
> index e4fd40f..b00fa92 100644
> --- a/tools/perf/ui/browsers/hists.c
> +++ b/tools/perf/ui/browsers/hists.c
> @@ -2017,7 +2017,8 @@ skip_annotation:
> &options[nr_options], dso);
> nr_options += add_map_opt(browser, &actions[nr_options],
> &options[nr_options],
> - browser->selection->map);
> + browser->selection ?
> + browser->selection->map : NULL);
> nr_options += add_socket_opt(browser, &actions[nr_options],
> &options[nr_options],
> socket);
> @@ -2030,7 +2031,10 @@ skip_annotation:
> nr_options += add_script_opt(browser,
> &actions[nr_options],
> &options[nr_options],
> - NULL, browser->selection->sym);
> + NULL,
> + browser->selection ?
> + browser->selection->sym :
> + NULL);

Is this really needed? IIUC browser->selection is not NULL if
browser->he_selection is not NULL. Did you see a case it's NULL?
Also passing a NULL thread and a NULL sym is meaningless here since
it's a duplication..

Thanks,
Namhyung


> }
> nr_options += add_script_opt(browser, &actions[nr_options],
> &options[nr_options], NULL, NULL);
> --
> 1.8.3.4
>


\
 
 \ /
  Last update: 2015-09-11 18:41    [W:0.080 / U:0.212 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site