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authorCong Wang <xiyou.wangcong@gmail.com>2014-10-21 09:27:12 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-11-14 08:47:58 -0800
commitf95ad6ed20948dee0a7c1472250b530136f75db3 (patch)
treef9183751531d9d0850fb925347d50012f39f7962 /kernel
parent6ce75ebb5334c12febaf520682926ce34c3cfe2b (diff)
downloadlinux-linaro-stable-f95ad6ed20948dee0a7c1472250b530136f75db3.tar.gz
freezer: Do not freeze tasks killed by OOM killer
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@suse.cz: rewrote the changelog] Fixes: a3201227f803 (freezer: make freezing() test freeze conditions in effect instead of TIF_FREEZE) Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/freezer.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/freezer.c b/kernel/freezer.c
index 78758512b1e1..bd733f6e610d 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -42,6 +42,9 @@ bool freezing_slow_path(struct task_struct *p)
if (p->flags & PF_NOFREEZE)
return false;
+ if (test_thread_flag(TIF_MEMDIE))
+ return false;
+
if (pm_nosig_freezing || cgroup_freezing(p))
return true;