Re: [PATCH] perf hists browser: Fix segfault when all entries be filtered

[He Kuang <hekuang@huawei.com>]

ping..
On 2015/3/4 12:13, He Kuang wrote:
> When all perf report entries be filtered, the result of
> hists__filter_entries() can be NULL, check the result before processing.
>
> Miss this checking will cause segmentation fault like this:
>
>    $ perf report
>
> (filter all entries and left nothing, then zoom in/out)
>    perf: Segmentation fault
>    -------- backtrace --------
>    ../bin/perf[0x4d1858]
>    ../lib64/libc.so.6(+0x3545f)[0x7fe72fc1145f]
>    ../bin/perf[0x4cd9f5]
>    ../bin/perf[0x4ce176]
>    ../bin/perf[0x4d0506]
>    ../bin/perf[0x41a94f]
>    ../bin/perf[0x408cf2]
>    ../bin/perf[0x408455]
>    ../lib64/libc.so.6(__libc_start_main+0xf4)[0x7fe72fbfdbd4]
>    ../bin/perf[0x408584]
>
> Signed-off-by: He Kuang <hekuang@huawei.com>
> ---
>   tools/perf/ui/browsers/hists.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
> index 788506e..1106bb8 100644
> --- a/tools/perf/ui/browsers/hists.c
> +++ b/tools/perf/ui/browsers/hists.c
> @@ -992,6 +992,9 @@ static void ui_browser__hists_seek(struct ui_browser *browser,
>   	 * and stop when we printed enough lines to fill the screen.
>   	 */
>   do_offset:
> +	if (!nd)
> +		return;
> +
>   	if (offset > 0) {
>   		do {
>   			h = rb_entry(nd, struct hist_entry, rb_node);