Re: [PATCH] perf-probe: Accept the instance number of kretprobe event

[Arnaldo Carvalho de Melo]

Em Wed, May 06, 2020 at 11:29:12PM +0900, Masami Hiramatsu escreveu:
> Since the commit 6a13a0d7b4d1 ("ftrace/kprobe: Show the
> maxactive number on kprobe_events") introduced to show the
> instance number of kretprobe events, the length of the 1st
> format of the kprobe event will not 1, but it can be longer.
> This caused a parser error in perf-probe.

Thanks for the quick fix!

I'll add this right after the Fixes tag:

Reported-by: yshuiv7@xxxxxxxxx
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=207587

Ok?

yshuiv, can I have your name to add to that Reported-by tag? And if you
test it, please, I can add a Tested-by: tag as well, credits where
credits are due!

Thanks!

- Arnaldo
 
> Skip the length check the 1st format of the kprobe event
> to accept this instance number.
> 
> Without this fix:
> 
>   # perf probe -a vfs_read%return
>   Added new event:
>     probe:vfs_read__return (on vfs_read%return)
> 
>   You can now use it in all perf tools, such as:
> 
>   	perf record -e probe:vfs_read__return -aR sleep 1
> 
>   # perf probe -l
>   Semantic error :Failed to parse event name: r16:probe/vfs_read__return
>     Error: Failed to show event list.
> 
> And with this fixes:
> 
>   # perf probe -a vfs_read%return
>   ...
>   # perf probe -l
>     probe:vfs_read__return (on vfs_read%return)
> 
> 
> Fixes: 6a13a0d7b4d1 ("ftrace/kprobe: Show the maxactive number on kprobe_events")
> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=207587
> ---
>  tools/perf/util/probe-event.c |    3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index eea132f512b0..c6bcf5709564 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -1765,8 +1765,7 @@ int parse_probe_trace_command(const char *cmd, struct probe_trace_event *tev)
>  	fmt1_str = strtok_r(argv0_str, ":", &fmt);
>  	fmt2_str = strtok_r(NULL, "/", &fmt);
>  	fmt3_str = strtok_r(NULL, " \t", &fmt);
> -	if (fmt1_str == NULL || strlen(fmt1_str) != 1 || fmt2_str == NULL
> -	    || fmt3_str == NULL) {
> +	if (fmt1_str == NULL || fmt2_str == NULL || fmt3_str == NULL) {
>  		semantic_error("Failed to parse event name: %s\n", argv[0]);
>  		ret = -EINVAL;
>  		goto out;
> 

-- 

- Arnaldo