diff mbox

perf hists browser: Fix segfault if use symbol filter in cmdline

Message ID 1449055732-235627-1-git-send-email-wangnan0@huawei.com
State Superseded
Headers show

Commit Message

Wang Nan Dec. 2, 2015, 11:28 a.m. UTC
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.

Signed-off-by: Wang Nan <wangnan0@huawei.com>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/ui/browsers/hists.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

-- 
1.8.3.4

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Comments

Wang Nan Dec. 3, 2015, 2:19 a.m. UTC | #1
On 2015/12/2 23:49, Namhyung Kim wrote:
> 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 <wangnan0@huawei.com>

>> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>

> Acked-by: Namhyung Kim <namhyung@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.


I know it. Add it only for correctness.

Will be removed.

Thank you.

> 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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diff mbox

Patch

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;
 	bool has_children;
 
+	if (!ms)
+		return false;
+
 	if (ms == &he->ms)
 		has_children = hist_entry__toggle_fold(he);
 	else