From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + oom-add-per-mm-oom-disable-count-protect-oom_disable_count-with-task_lock-in-fork.patch added to -mm tree Date: Thu, 16 Sep 2010 15:50:27 -0700 Message-ID: <201009162250.o8GMoSug018489@imap1.linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:50596 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755640Ab0IPWup (ORCPT ); Thu, 16 Sep 2010 18:50:45 -0400 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: mm-commits@vger.kernel.org Cc: rientjes@google.com, kamezawa.hiroyu@jp.fujitsu.com, kosaki.motohiro@jp.fujitsu.com, riel@redhat.com, yinghan@google.com The patch titled oom: protect oom_disable_count with task_lock in fork has been added to the -mm tree. Its filename is oom-add-per-mm-oom-disable-count-protect-oom_disable_count-with-task_lock-in-fork.patch 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/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: oom: protect oom_disable_count with task_lock in fork From: David Rientjes task_lock(p) protects p->mm->oom_disable_count such that it accurately represents the number of threads attached to that mm that cannot be killed by the oom killer. p->signal->oom_score_adj is never changed without holding the lock. This was missed in the fork() path, so we take the lock to ensure checking its oom_score_adj and decrementing oom_disable_count don't race. Reported-by: KOSAKI Motohiro Signed-off-by: David Rientjes Cc: Ying Han Cc: KAMEZAWA Hiroyuki Cc: Rik van Riel Signed-off-by: Andrew Morton --- kernel/fork.c | 2 ++ 1 file changed, 2 insertions(+) diff -puN kernel/fork.c~oom-add-per-mm-oom-disable-count-protect-oom_disable_count-with-task_lock-in-fork kernel/fork.c --- a/kernel/fork.c~oom-add-per-mm-oom-disable-count-protect-oom_disable_count-with-task_lock-in-fork +++ a/kernel/fork.c @@ -1304,8 +1304,10 @@ bad_fork_cleanup_namespaces: exit_task_namespaces(p); bad_fork_cleanup_mm: if (p->mm) { + task_lock(p); if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) atomic_dec(&p->mm->oom_disable_count); + task_unlock(p); mmput(p->mm); } bad_fork_cleanup_signal: _ Patches currently in -mm which might be from rientjes@google.com are oom-always-return-a-badness-score-of-non-zero-for-eligible-tasks.patch linux-next.patch oom-filter-unkillable-tasks-from-tasklist-dump.patch oom-add-per-mm-oom-disable-count.patch oom-add-per-mm-oom-disable-count-protect-oom_disable_count-with-task_lock-in-fork.patch oom-add-per-mm-oom-disable-count-use-old_mm-for-oom_disable_count-in-exec.patch oom-avoid-killing-a-task-if-a-thread-sharing-its-mm-cannot-be-killed.patch oom-kill-all-threads-sharing-oom-killed-tasks-mm.patch oom-kill-all-threads-sharing-oom-killed-tasks-mm-fix.patch oom-kill-all-threads-sharing-oom-killed-tasks-mm-fix-fix.patch oom-rewrite-error-handling-for-oom_adj-and-oom_score_adj-tunables.patch oom-fix-locking-for-oom_adj-and-oom_score_adj.patch mm-mempolicy-check-return-code-of-check_range.patch jbd-remove-dependency-on-__gfp_nofail.patch