Re: [PATCH 5.10 65/73] exit: wait_task_zombie: kill the no longer necessary spin_lock_irq(siglock)

I do not know what does 5.10 mean. Does this tree has all the changes this patch depends on? Say, 1df4bd83cdfdbd0720dd ("do_io_accounting: use sig->stats_lock") ?

In any case please remove this patch from all your queues, it got the "stable" tag by mistake.

Oleg.

On 03/13, Sasha Levin wrote:

From: Oleg Nesterov oleg@redhat.com

[ Upstream commit c1be35a16b2f1fe21f4f26f9de030ad6eaaf6a25 ]

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 Signed-off-by: Sasha Levin sashal@kernel.org

---

kernel/exit.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/kernel/exit.c b/kernel/exit.c index c41bdc0a7f06b..8f25abdd5fa7d 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1106,17 +1106,14 @@ 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;

@@ -1139,8 +1136,7 @@ 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) -- 2.43.0