Re: [PATCH 21/25] perf evsel: Skip ignored symbols while printingcallchain

From: Adrian Hunter
Date: Tue Nov 26 2013 - 05:44:55 EST


On 25/11/13 16:17, Arnaldo Carvalho de Melo wrote:
> From: David Ahern <dsahern@xxxxxxxxx>
>
> Allows a command to have a symbol_filter controlled by the user to skip
> certain functions in a backtrace. One example is to allow the user to
> reduce repeating patterns like:
>
> do_select core_sys_select sys_select
>
> to just sys_select when dumping callchains, consuming less real estate
> on the screen while still conveying the essential message - the process
> is in a select call.
>
> This option is leveraged by the upcoming timehist command.
>
> Signed-off-by: David Ahern <dsahern@xxxxxxxxx>
> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Stephane Eranian <eranian@xxxxxxxxxx>
> Link: http://lkml.kernel.org/r/1384806771-2945-2-git-send-email-dsahern@xxxxxxxxx
> Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> ---
> tools/perf/util/session.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index f36d24a02445..948f7644b4d9 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -1522,6 +1522,9 @@ void perf_evsel__print_ip(struct perf_evsel *evsel, union perf_event *event,
> if (!node)
> break;
>
> + if (node->sym && node->sym->ignore)
> + goto next;
> +
> if (print_ip)
> printf("%c%16" PRIx64, s, node->ip);
>
> @@ -1544,12 +1547,15 @@ void perf_evsel__print_ip(struct perf_evsel *evsel, union perf_event *event,
> if (!print_oneline)
> printf("\n");
>
> - callchain_cursor_advance(&callchain_cursor);
> -
> stack_depth--;
> +next:
> + callchain_cursor_advance(&callchain_cursor);
> }
>
> } else {
> + if (al.sym->ignore)

Seems to segfault here because sym is null

> + return;
> +
> if (print_ip)
> printf("%16" PRIx64, sample->ip);
>
>

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