Re: [PATCH] selftests/tracing: Fix flakiness in trigger-hist-poll.tc by waiting for task exit

[Steven Rostedt]

On Tue, 21 Jul 2026 09:20:36 +0900

I'm finally getting around to looking at this!

"Masami Hiramatsu (Google)" <mhiramat@xxxxxxxxxx> wrote:

> diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc
> index 04eb8546fc07..d54d54f9ec77 100644
> --- a/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc
> +++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc
> @@ -38,11 +38,7 @@ BGPID=$!
>  ${POLL} -I -t 4000 ${EVENT}/hist
>  echo 0 > tracing_on
>  
> -if [ -d /proc/${BGPID} ]; then
> -  echo "poll exits too soon"
> -  kill -KILL ${BGPID} ||:
> -  exit_fail
> -fi
> +wait ${BGPID} 2>/dev/null ||:
>  
>  if ! grep -qw "sleep" trace; then
>    echo "poll exits before event happens"
> @@ -60,11 +56,7 @@ BGPID=$!
>  ${POLL} -P -t 4000 ${EVENT}/hist
>  echo 0 > tracing_on
>  
> -if [ -d /proc/${BGPID} ]; then
> -  echo "poll exits too soon"
> -  kill -KILL ${BGPID} ||:
> -  exit_fail
> -fi
> +wait ${BGPID} 2>/dev/null ||:
>  
>  if ! grep -qw "sleep" trace; then
>    echo "poll exits before event happens"
> @@ -72,3 +64,5 @@ if ! grep -qw "sleep" trace; then
>  fi
>  
>  exit_pass
> +
> +

Hmm, any reason for the two added newlines here?

-- Steve