linux-kernel - [PATCH 3/3] perf hists browser: Fix segfault when showing callchain

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1420731408-8631-4-git-send-email-acme@kernel.org>
Date:	Thu,  8 Jan 2015 12:36:48 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	linux-kernel@...r.kernel.org, Namhyung Kim <namhyung@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Andi Kleen <andi@...stfloor.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Jiri Olsa <jolsa@...hat.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Stephane Eranian <eranian@...gle.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 3/3] perf hists browser: Fix segfault when showing callchain

From: Namhyung Kim <namhyung@...nel.org>

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@...nel.org>
Fixes: 4087d11cd945 ("perf hists browser: Print overhead percent value for first-level callchain")
Cc: Adrian Hunter <adrian.hunter@...el.com>
Cc: Andi Kleen <andi@...stfloor.org>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Stephane Eranian <eranian@...gle.com>
Link: http://lkml.kernel.org/r/1419401076-21700-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/ui/browsers/hists.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
index e6bb04b5b09b..788506eef567 100644
--- a/tools/perf/ui/browsers/hists.c
+++ b/tools/perf/ui/browsers/hists.c
@@ -550,7 +550,7 @@ static int hist_browser__show_callchain(struct hist_browser *browser,
 	bool need_percent;
 
 	node = rb_first(root);
-	need_percent = !!rb_next(node);
+	need_percent = node && rb_next(node);
 
 	while (node) {
 		struct callchain_node *child = rb_entry(node, struct callchain_node, rb_node);
-- 
1.9.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/