When perf report on TUI shows callchain it checks first node has
siblings to determine whether it needs to print percentage value.
But it missed a case that first node is NULL. So sometimes it segfaults
like below:
$ perf top -g
perf: Segmentation fault
-------- backtrace --------
perf[0x4fcefb]
/usr/lib/libc.so.6(+0x33b20)[0x7f2a35839b20]
perf(rb_next+0x8)[0x47d3d8]
perf[0x4f6058]
perf[0x4f833b]
perf[0x4f8610]
perf[0x4f209e]
perf(ui_browser__run+0x3a)[0x4f2e6a]
perf[0x4f94ee]
perf(perf_evlist__tui_browse_hists+0x94)[0x4fbbf4]
perf[0x444d10]
/usr/lib/libpthread.so.0(+0x7314)[0x7f2a37070314]
/usr/lib/libc.so.6(clone+0x6d)[0x7f2a358ee5bd]
$ addr2line -e `which perf` 0x4f6058
/home/namhyung/project/linux/tools/perf/ui/browsers/hists.c:553
I don't know why the backtrace didn't print some symbols..
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Fixes: 4087d11cd9 ("perf hists browser: Print overhead percent value for first-level callchain")
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1419401076-21700-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
c09e31cc12