From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f174.google.com (mail-wi0-f174.google.com [209.85.212.174]) by kanga.kvack.org (Postfix) with ESMTP id 9388B6B0038 for ; Wed, 26 Aug 2015 10:12:37 -0400 (EDT) Received: by wicja10 with SMTP id ja10so45999951wic.1 for ; Wed, 26 Aug 2015 07:12:37 -0700 (PDT) Received: from mail-wi0-f176.google.com (mail-wi0-f176.google.com. [209.85.212.176]) by mx.google.com with ESMTPS id ev15si5386957wjd.117.2015.08.26.07.12.35 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 26 Aug 2015 07:12:36 -0700 (PDT) Received: by wijn1 with SMTP id n1so25850616wij.0 for ; Wed, 26 Aug 2015 07:12:35 -0700 (PDT) Date: Wed, 26 Aug 2015 16:12:33 +0200 From: Michal Hocko Subject: Re: [REPOST] [PATCH 2/2] mm,oom: Reverse the order of setting TIF_MEMDIE and sending SIGKILL. Message-ID: <20150826141233.GI25196@dhcp22.suse.cz> References: <201508231619.CGF82826.MJtVLSHOFFQOOF@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201508231619.CGF82826.MJtVLSHOFFQOOF@I-love.SAKURA.ne.jp> Sender: owner-linux-mm@kvack.org List-ID: To: Oleg Nesterov Cc: Tetsuo Handa , rientjes@google.com, hannes@cmpxchg.org, linux-mm@kvack.org Hi Oleg, On Sun 23-08-15 16:19:38, Tetsuo Handa wrote: [...] > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index 5249e7e..c0a5a69 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -555,12 +555,17 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p, > /* Get a reference to safely compare mm after task_unlock(victim) */ > mm = victim->mm; > atomic_inc(&mm->mm_users); > - mark_oom_victim(victim); > pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n", > task_pid_nr(victim), victim->comm, K(victim->mm->total_vm), > K(get_mm_counter(victim->mm, MM_ANONPAGES)), > K(get_mm_counter(victim->mm, MM_FILEPAGES))); > task_unlock(victim); > + /* Send SIGKILL before setting TIF_MEMDIE. */ > + do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, true); > + task_lock(victim); > + if (victim->mm) > + mark_oom_victim(victim); > + task_unlock(victim); I cannot seem to find any explicit note about task_lock vs. signal nesting nor task_lock() anywhere in kernel/signal.c so I rather ask. Can we call do_send_sig_info with task_lock held? Thanks! -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org