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From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>,
	Kyle Walker <kwalker@redhat.com>,
	Michal Hocko <mhocko@kernel.org>,
	Stanislav Kozina <skozina@redhat.com>,
	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	linux-kernel@vger.kernel.org
Subject: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong fatal_signal_pending() check in oom_kill_process()
Date: Wed, 30 Sep 2015 20:24:05 +0200	[thread overview]
Message-ID: <20150930182405.GA15238@redhat.com> (raw)
In-Reply-To: <20150930182341.GA15047@redhat.com>

The fatal_signal_pending() was added to suppress unnecessary "sharing
same memory" message, but it can't 100% help anyway because it can be
false-negative; SIGKILL can be already dequeued.

And worse, it can be false-positive due to exec or coredump. exec is
mostly fine, but coredump is not. It is possible that the group leader
has the pending SIGKILL because its sub-thread originated the coredump,
in this case we must not skip this process.

We could probably add the additional ->group_exit_task check but this
pach just removes the wrong check along with pr_info().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 mm/oom_kill.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 4766e25..b6b8c78 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -588,11 +588,7 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
 		    !(p->flags & PF_KTHREAD)) {
 			if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
 				continue;
-			if (fatal_signal_pending(p))
-				continue;
 
-			pr_info("Kill process %d (%s) sharing same memory\n",
-				task_pid_nr(p), p->comm);
 			do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
 		}
 	rcu_read_unlock();
-- 
2.4.3


  reply	other threads:[~2015-09-30 18:27 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-29 14:17 [PATCH -mm 0/3] mm/oom_kill: ensure we actually kill all tasks sharing the same mm Oleg Nesterov
2015-09-29 14:18 ` [PATCH -mm 1/3] mm/oom_kill: remove the wrong fatal_signal_pending() Oleg Nesterov
2015-09-29 22:36   ` David Rientjes
2015-09-30  1:42     ` Tetsuo Handa
2015-09-30 13:47       ` Oleg Nesterov
2015-09-30 15:20         ` [PATCH -mm 1/3] mm/oom_kill: remove the wrongfatal_signal_pending() Tetsuo Handa
2015-09-30 13:43     ` [PATCH -mm 1/3] mm/oom_kill: remove the wrong fatal_signal_pending() Oleg Nesterov
2015-09-29 14:18 ` [PATCH -mm 2/3] mm/oom_kill: cleanup the "kill sharing same memory" Oleg Nesterov
2015-09-29 22:39   ` David Rientjes
2015-09-30 13:49     ` Oleg Nesterov
2015-09-29 14:18 ` [PATCH -mm 3/3] mm/oom_kill: fix the wrong task->mm == mm checks in Oleg Nesterov
2015-09-29 22:41   ` David Rientjes
2015-09-30 13:50     ` Oleg Nesterov
2015-09-30  2:16   ` Tetsuo Handa
2015-09-30 13:59     ` Oleg Nesterov
2015-09-30 18:23 ` [PATCH -mm v2 0/3] mm/oom_kill: ensure we actually kill all tasks sharing the same mm Oleg Nesterov
2015-09-30 18:24   ` Oleg Nesterov [this message]
2015-09-30 21:14     ` [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong fatal_signal_pending() check in oom_kill_process() David Rientjes
2015-10-01 10:52       ` [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong fatal_signal_pending()check " Tetsuo Handa
2015-10-01 12:49     ` [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong fatal_signal_pending() check " Michal Hocko
2015-10-01 15:00       ` Oleg Nesterov
2015-10-01 15:27         ` Michal Hocko
2015-10-01 15:41           ` Oleg Nesterov
2015-10-01 16:19             ` Michal Hocko
2015-10-01 17:53               ` Oleg Nesterov
2015-10-02 11:32                 ` Tetsuo Handa
2015-10-02 12:11                   ` Michal Hocko
2015-10-02 12:33                     ` Tetsuo Handa
2015-10-02 13:32                       ` Michal Hocko
2015-10-02 13:57                         ` Oleg Nesterov
2015-10-02 14:24                           ` Michal Hocko
2015-10-02 14:07                         ` Tetsuo Handa
2015-10-02 14:15                           ` Oleg Nesterov
2015-10-02 13:52                   ` Oleg Nesterov
2015-10-02 14:36                     ` Tetsuo Handa
2015-09-30 18:24   ` [PATCH -mm v2 2/3] mm/oom_kill: cleanup the "kill sharing same memory" loop Oleg Nesterov
2015-09-30 21:15     ` David Rientjes
2015-10-01 12:50     ` Michal Hocko
2015-09-30 18:24   ` [PATCH -mm v2 3/3] mm/oom_kill: fix the wrong task->mm == mm checks in oom_kill_process() Oleg Nesterov
2015-09-30 21:15     ` David Rientjes
2015-10-01 12:56     ` Michal Hocko
2015-10-01 22:24     ` Andrew Morton

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