Currently, the oom killer will attempt to kill a process that is in
TASK_UNINTERRUPTIBLE state. For tasks in this state for an exceptional
period of time, such as processes writing to a frozen filesystem during
a lengthy backup operation, this can result in a deadlock condition as
related processes memory access will stall within the page fault
handler.
Within oom_unkillable_task(), check for processes in
TASK_UNINTERRUPTIBLE (TASK_KILLABLE omitted). The oom killer will
move on to another task.
Signed-off-by: Kyle Walker <kwal...@redhat.com>
---
mm/oom_kill.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 1ecc0bc..66f03f8 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -131,6 +131,10 @@ static bool oom_unkillable_task(struct task_struct *p,
if (memcg && !task_in_mem_cgroup(p, memcg))
return true;
+ /* Uninterruptible tasks should not be killed unless in TASK_WAKEKILL */
+ if (p->state == TASK_UNINTERRUPTIBLE)
+ return true;
+
/* p may not have freeable memory in nodemask */
if (!has_intersects_mems_allowed(p, nodemask))
return true;
--
2.4.3
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