From bd315aab8a3ab1bc7074774b89a5d8ec7c1ff7ab Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Mon, 14 Sep 2015 10:23:55 +0000 Subject: [PATCH] perf top: Fix segfault pressing -> with no hist entries 'perf top' segfaults with following operation: # perf top -e page-faults -p 11400 # 11400 never generates 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 resides 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 checking browser->selection before fetching browser->selection->map. Signed-off-by: Wang Nan Tested-by: Arnaldo Carvalho de Melo Cc: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1442226235-117265-1-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/ui/browsers/hists.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c index cf86f2d3a5e7..c04c60d4863c 100644 --- a/tools/perf/ui/browsers/hists.c +++ b/tools/perf/ui/browsers/hists.c @@ -1968,7 +1968,8 @@ 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); /* perf script support */ if (browser->he_selection) { @@ -1976,6 +1977,15 @@ skip_annotation: &actions[nr_options], &options[nr_options], thread, NULL); + /* + * Note that browser->selection != NULL + * when browser->he_selection is not NULL, + * so we don't need to check browser->selection + * before fetching browser->selection->sym like what + * we do before fetching browser->selection->map. + * + * See hist_browser__show_entry. + */ nr_options += add_script_opt(browser, &actions[nr_options], &options[nr_options], -- 2.20.1