Re: [PATCH] perf trace: Segfault when trying to trace events by cgroup

[Stanislav Ivanichkin <sivanichkin@yandex-team.ru>]

Hi,

+linux-perf-users@

Gentle ping for this patch

Many Thanks

--
Stanislav Ivanichkin

> On 9 Oct 2020, at 09:45, Stanislav Ivanichkin <sivanichkin@yandex-team.ru> wrote:
> 
> # ./perf trace -e sched:sched_switch -G test -a sleep 1
> perf: Segmentation fault
> Obtained 11 stack frames.
> ./perf(sighandler_dump_stack+0x43) [0x55cfdc636db3]
> /lib/x86_64-linux-gnu/libc.so.6(+0x3efcf) [0x7fd23eecafcf]
> ./perf(parse_cgroups+0x36) [0x55cfdc673f36]
> ./perf(+0x3186ed) [0x55cfdc70d6ed]
> ./perf(parse_options_subcommand+0x629) [0x55cfdc70e999]
> ./perf(cmd_trace+0x9c2) [0x55cfdc5ad6d2]
> ./perf(+0x1e8ae0) [0x55cfdc5ddae0]
> ./perf(+0x1e8ded) [0x55cfdc5ddded]
> ./perf(main+0x370) [0x55cfdc556f00]
> /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe6) [0x7fd23eeadb96]
> ./perf(_start+0x29) [0x55cfdc557389]
> Segmentation fault
> 
> It happens because "struct trace" in option->value is passed to
> parse_cgroups function instead of "struct evlist".
> 
> Signed-off-by: Stanislav Ivanichkin <sivanichkin@yandex-team.ru>
> Reviewed-by: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
> ---
> tools/perf/builtin-trace.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
> index bea461b6f937..cbc4de6840db 100644
> --- a/tools/perf/builtin-trace.c
> +++ b/tools/perf/builtin-trace.c
> @@ -4651,9 +4651,12 @@ static int trace__parse_cgroups(const struct option *opt, const char *str, int u
> {
> 	struct trace *trace = opt->value;
> 
> -	if (!list_empty(&trace->evlist->core.entries))
> -		return parse_cgroups(opt, str, unset);
> -
> +	if (!list_empty(&trace->evlist->core.entries)) {
> +		struct option o = OPT_CALLBACK('G', "cgroup", &trace->evlist,
> +			"name", "monitor event in cgroup name only",
> +			parse_cgroups);
> +		return parse_cgroups(&o, str, unset);
> +	}
> 	trace->cgroup = evlist__findnew_cgroup(trace->evlist, str);
> 
> 	return 0;
> -- 
> 2.17.1
>