Hi,
On Wed, Dec 02, 2015 at 11:28:52AM +0000, Wang Nan wrote:
> If feed perf a symbol filter in cmdline and the result is empty,
> pressing 'Enter' in the hist browser causes crash:
>
> # ./perf report perf.data <-- Common mistake for beginners
>
> Then press 'Enter':
>
> perf: Segmentation fault
> -------- backtrace --------
> /home/wangnan/perf[0x53e578]
> /lib64/libc.so.6(+0x3545f)[0x7f76bafe045f]
> /home/wangnan/perf[0x539dd4]
> /home/wangnan/perf(perf_evlist__tui_browse_hists+0x96)[0x53d216]
> /home/wangnan/perf(cmd_report+0x1b9f)[0x442c7f]
> /home/wangnan/perf[0x47efa2]
> /home/wangnan/perf(main+0x5f5)[0x432fa5]
> /lib64/libc.so.6(__libc_start_main+0xf4)[0x7f76bafccbd4]
> /home/wangnan/perf[0x4330d4]
>
> This is because 'perf.data' is interperted as a symbol filter, and the
> result is empty, so selection is empty. However,
> hist_browser__toggle_fold() forgets to check it.
>
> This patch simply return faluse when selection is NULL.
s/faluse/false/
>
> Signed-off-by: Wang Nan <wangn...@huawei.com>
> Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Acked-by: Namhyung Kim <namhy...@kernel.org>
One nitpick below..
> ---
> tools/perf/ui/browsers/hists.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
> index dcdcbaf..33da341 100644
> --- a/tools/perf/ui/browsers/hists.c
> +++ b/tools/perf/ui/browsers/hists.c
> @@ -337,9 +337,12 @@ static bool hist_browser__toggle_fold(struct
> hist_browser *browser)
> {
> struct hist_entry *he = browser->he_selection;
> struct map_symbol *ms = browser->selection;
> - struct callchain_list *cl = container_of(ms, struct callchain_list, ms);
> + struct callchain_list *cl = ms ? container_of(ms, struct
> callchain_list, ms) : NULL;
I think this line is not needed as container_of doesn't make a pointer
dereference by itself. Just checking below is enough IMHO.
Thanks,
Namhyung
> bool has_children;
>
> + if (!ms)
> + return false;
> +
> if (ms == &he->ms)
> has_children = hist_entry__toggle_fold(he);
> else
> --
> 1.8.3.4
>
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