From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + oom-kill-all-threads-sharing-oom-killed-tasks-mm-fix.patch added to -mm tree Date: Tue, 24 Aug 2010 15:50:28 -0700 Message-ID: <201008242250.o7OMoSgd019457@imap1.linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:35180 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755708Ab0HXWvM (ORCPT ); Tue, 24 Aug 2010 18:51:12 -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, akpm@linux-foundation.org, kamezawa.hiroyu@jp.fujitsu.com, kosaki.motohiro@jp.fujitsu.com, riel@redhat.com, yinghan@google.com The patch titled oom: protect task name when killing threads sharing memory has been added to the -mm tree. Its filename is oom-kill-all-threads-sharing-oom-killed-tasks-mm-fix.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 task name when killing threads sharing memory From: David Rientjes It's necessary to prevent dereferences of q->comm for a task q when q != current because its name may change during prctl() with PR_SET_NAME. Unfortunately, we can't use get_task_comm() when killing other threads sharing the same memory as the oom killed task since it would require a string to be allocated on the stack which may be very deep, especially during failed page allocations. This patch protects the dereference with task_lock() instead. Suggested-by: Andrew Morton Signed-off-by: David Rientjes Cc: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro Cc: Rik van Riel Cc: Ying Han Signed-off-by: Andrew Morton --- mm/oom_kill.c | 2 ++ 1 file changed, 2 insertions(+) diff -puN mm/oom_kill.c~oom-kill-all-threads-sharing-oom-killed-tasks-mm-fix mm/oom_kill.c --- a/mm/oom_kill.c~oom-kill-all-threads-sharing-oom-killed-tasks-mm-fix +++ a/mm/oom_kill.c @@ -429,8 +429,10 @@ static int oom_kill_task(struct task_str */ for_each_process(q) if (q->mm == mm && !same_thread_group(q, p)) { + task_lock(q); pr_err("Kill process %d (%s) sharing same memory\n", task_pid_nr(q), q->comm); + task_unlock(q); force_sig(SIGKILL, q); } _ Patches currently in -mm which might be from rientjes@google.com are linux-next.patch oom-add-per-mm-oom-disable-count.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 jbd-remove-dependency-on-__gfp_nofail.patch