This is a note to let you know that I've just added the patch titled
freezer: Do not freeze tasks killed by OOM killer
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
freezer-do-not-freeze-tasks-killed-by-oom-killer.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 51fae6da640edf9d266c94f36bc806c63c301991 Mon Sep 17 00:00:00 2001
From: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Date: Tue, 21 Oct 2014 09:27:12 +0200
Subject: freezer: Do not freeze tasks killed by OOM killer
From: Cong Wang <xiyou.wangcong@xxxxxxxxx>
commit 51fae6da640edf9d266c94f36bc806c63c301991 upstream.
Since f660daac474c6f (oom: thaw threads if oom killed thread is frozen
before deferring) OOM killer relies on being able to thaw a frozen task
to handle OOM situation but a3201227f803 (freezer: make freezing() test
freeze conditions in effect instead of TIF_FREEZE) has reorganized the
code and stopped clearing freeze flag in __thaw_task. This means that
the target task only wakes up and goes into the fridge again because the
freezing condition hasn't changed for it. This reintroduces the bug
fixed by f660daac474c6f.
Fix the issue by checking for TIF_MEMDIE thread flag in
freezing_slow_path and exclude the task from freezing completely. If a
task was already frozen it would get woken by __thaw_task from OOM killer
and get out of freezer after rechecking freezing().
Changes since v1
- put TIF_MEMDIE check into freezing_slowpath rather than in __refrigerator
as per Oleg
- return __thaw_task into oom_scan_process_thread because
oom_kill_process will not wake task in the fridge because it is
sleeping uninterruptible
[mhocko@xxxxxxx: rewrote the changelog]
Fixes: a3201227f803 (freezer: make freezing() test freeze conditions in effect instead of TIF_FREEZE)
Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Signed-off-by: Michal Hocko <mhocko@xxxxxxx>
Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/freezer.c | 3 +++
1 file changed, 3 insertions(+)
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -42,6 +42,9 @@ bool freezing_slow_path(struct task_stru
if (p->flags & (PF_NOFREEZE | PF_SUSPEND_TASK))
return false;
+ if (test_thread_flag(TIF_MEMDIE))
+ return false;
+
if (pm_nosig_freezing || cgroup_freezing(p))
return true;
Patches currently in stable-queue which might be from xiyou.wangcong@xxxxxxxxx are
queue-3.14/freezer-do-not-freeze-tasks-killed-by-oom-killer.patch
queue-3.14/vxlan-using-pskb_may_pull-as-early-as-possible.patch
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