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authorOleg Nesterov <oleg@redhat.com>2024-01-23 16:34:00 +0100
committerAndrew Morton <akpm@linux-foundation.org>2024-02-07 21:20:33 -0800
commitc1be35a16b2f1fe21f4f26f9de030ad6eaaf6a25 (patch)
treed7ca24b5723bb9e8aaec90de0e06f9d22c026972
parent7601df8031fd67310af891897ef6cc0df4209305 (diff)
exit: wait_task_zombie: kill the no longer necessary spin_lock_irq(siglock)
After the recent changes nobody use siglock to read the values protected by stats_lock, we can kill spin_lock_irq(&current->sighand->siglock) and update the comment. With this patch only __exit_signal() and thread_group_start_cputime() take stats_lock under siglock. Link: https://lkml.kernel.org/r/20240123153359.GA21866@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Dylan Hatch <dylanbhatch@google.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--kernel/exit.c10
1 files changed, 3 insertions, 7 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 3988a02efaef..dfb963d2f862 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1127,17 +1127,14 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
* and nobody can change them.
*
* psig->stats_lock also protects us from our sub-threads
- * which can reap other children at the same time. Until
- * we change k_getrusage()-like users to rely on this lock
- * we have to take ->siglock as well.
+ * which can reap other children at the same time.
*
* We use thread_group_cputime_adjusted() to get times for
* the thread group, which consolidates times for all threads
* in the group including the group leader.
*/
thread_group_cputime_adjusted(p, &tgutime, &tgstime);
- spin_lock_irq(&current->sighand->siglock);
- write_seqlock(&psig->stats_lock);
+ write_seqlock_irq(&psig->stats_lock);
psig->cutime += tgutime + sig->cutime;
psig->cstime += tgstime + sig->cstime;
psig->cgtime += task_gtime(p) + sig->gtime + sig->cgtime;
@@ -1160,8 +1157,7 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
psig->cmaxrss = maxrss;
task_io_accounting_add(&psig->ioac, &p->ioac);
task_io_accounting_add(&psig->ioac, &sig->ioac);
- write_sequnlock(&psig->stats_lock);
- spin_unlock_irq(&current->sighand->siglock);
+ write_sequnlock_irq(&psig->stats_lock);
}
if (wo->wo_rusage)