From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 98B238C08; Wed, 24 Jan 2024 10:17:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706091452; cv=none; b=jkL1BFqet7MYI82m0Ypb3ET241SbIDswcpGcTpd4oWzR1Kkb78P49ag+kJbWI0Qk64mrqU/pltQsMsOtXmekdvDTUYDZi7y/Kwcu9Py2fiRBEMxsLE+OjjHlKEyd7SYmVHGQAlLKfU8gjg98ZwI1eolW+7JaBOYz42hjC3bhhI0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706091452; c=relaxed/simple; bh=O9A6yBZds1dVCfzvTKLXF7jzI6MmPn1h8mNNvyWzHao=; h=Date:To:From:Subject:Message-Id; b=aOthA9xqIcTOGeRVm24p03KaVeVRSrzTq2Hzdh5QNiz/Cn/ZGcItF5pCit2uveU/YdQ8zqq5TOCq13rbDUx70FE17gSY71Wt4qTeSG8MVUuqbHbB9+6LtS8MGDjn4GMmVZ28ur8ghYNlcFWYUrae1IgbFU7t1QOsgA1OE9rS9yk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=Bue/JsSy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="Bue/JsSy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 08858C43390; Wed, 24 Jan 2024 10:17:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1706091452; bh=O9A6yBZds1dVCfzvTKLXF7jzI6MmPn1h8mNNvyWzHao=; h=Date:To:From:Subject:From; b=Bue/JsSyfkyAqmqoImWccbiysCt1wZ0NM+IaGD6wGyyDDb1U2FEBuUS5XYFA7Sk0l AelKMFsu7uZvtSgk+asBGGDJ2f9LJb828zfufXfeedBb4tMi6KIOslHTaK/Wh1RODi CcCxmCuq0wptw0myEXOj5VmWXQHwD/S+5JgpUeUE= Date: Wed, 24 Jan 2024 02:17:29 -0800 To: mm-commits@vger.kernel.org,stable@vger.kernel.org,ebiederm@xmission.com,dylanbhatch@google.com,oleg@redhat.com,akpm@linux-foundation.org From: Andrew Morton Subject: + exit-wait_task_zombie-kill-the-no-longer-necessary-spin_lock_irqsiglock.patch added to mm-hotfixes-unstable branch Message-Id: <20240124101732.08858C43390@smtp.kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: exit: wait_task_zombie: kill the no longer necessary spin_lock_irq(siglock) has been added to the -mm mm-hotfixes-unstable branch. Its filename is exit-wait_task_zombie-kill-the-no-longer-necessary-spin_lock_irqsiglock.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/exit-wait_task_zombie-kill-the-no-longer-necessary-spin_lock_irqsiglock.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Oleg Nesterov Subject: exit: wait_task_zombie: kill the no longer necessary spin_lock_irq(siglock) Date: Tue, 23 Jan 2024 16:34:00 +0100 After the recent changes nobody use siglock to read the values protected by stats_lock, we can kill spin_lock_irq(¤t->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 Signed-off-by: Dylan Hatch Cc: Eric W. Biederman Cc: Signed-off-by: Andrew Morton --- kernel/exit.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) --- a/kernel/exit.c~exit-wait_task_zombie-kill-the-no-longer-necessary-spin_lock_irqsiglock +++ a/kernel/exit.c @@ -1127,17 +1127,14 @@ static int wait_task_zombie(struct wait_ * 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(¤t->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_ 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(¤t->sighand->siglock); + write_sequnlock_irq(&psig->stats_lock); } if (wo->wo_rusage) _ Patches currently in -mm which might be from oleg@redhat.com are getrusage-move-thread_group_cputime_adjusted-outside-of-lock_task_sighand.patch getrusage-use-sig-stats_lock-rather-than-lock_task_sighand.patch fs-proc-do_task_stat-move-thread_group_cputime_adjusted-outside-of-lock_task_sighand.patch fs-proc-do_task_stat-use-sig-stats_lock-to-gather-the-threads-children-stats.patch exit-wait_task_zombie-kill-the-no-longer-necessary-spin_lock_irqsiglock.patch ptrace_attach-shift-sendsigstop-into-ptrace_set_stopped.patch