Commit ed5378a3 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Andrew Morton
Browse files

taskstats: fill_stats_for_tgid: use for_each_thread() 

do/while_each_thread should be avoided when possible.

Plus I _think_ this change allows to avoid lock_task_sighand() but I am
not sure, I forgot everything about taskstats.  In any case, this code
does not look right in that the same thread can be accounted twice:
taskstats_exit() can account the exiting thread in signal->stats and drop
->siglock but this thread is still on the thread-group list, so
lock_task_sighand() can't help.

Link: https://lkml.kernel.org/r/20230909214951.GA24274@redhat.com


Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 13b7bc60

kernel/taskstats.c

+2 −3
Original line number Diff line number Diff line
@@ -233,9 +233,8 @@ static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats) 
	else

		memset(stats, 0, sizeof(*stats));



	tsk = first;

	start_time = ktime_get_ns();

	do {

	for_each_thread(first, tsk) {

		if (tsk->exit_state)

			continue;

		/*
@@ -258,7 +257,7 @@ static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats) 


		stats->nvcsw += tsk->nvcsw;

		stats->nivcsw += tsk->nivcsw;

	} while_each_thread(first, tsk);

	}



	unlock_task_sighand(first, &flags);

	rc = 0;