From: "wang, biao" <biao.wang@xxxxxxxxx>
Date: Thu, 30 Jul 2015 14:14:44 +0800
Subject: [PATCH] improve lmk to avoid deadlock issue
Consider the following case:
Task A trigger lmk with a lock held, while process B try to
get this lock, but unfortunately B is the very culprit Task lmk select to
kill.
So B will never be killed, and A will forever select B to kill and
such dead lock trigger softlock up issue.
This patch try to pick the next task to break this loop.
Signed-off-by: wang, biao <biao.wang@xxxxxxxxx>
Signed-off-by: Zhang Di <di.zhang@xxxxxxxxx>
---
drivers/staging/android/lowmemorykiller.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c
index feafa17..efabeb7 100644
--- a/drivers/staging/android/lowmemorykiller.c
+++ b/drivers/staging/android/lowmemorykiller.c
@@ -127,11 +127,15 @@ static unsigned long lowmem_scan(struct shrinker *s, struct shrink_control *sc)
if (!p)
continue;
- if (test_tsk_thread_flag(p, TIF_MEMDIE) &&
- time_before_eq(jiffies, lowmem_deathpending_timeout)) {
- task_unlock(p);
- rcu_read_unlock();
- return 0;
+ if (test_tsk_thread_flag(p, TIF_MEMDIE)) {
+ if (time_before_eq(jiffies, lowmem_deathpending_timeout)) {
+ task_unlock(p);
+ rcu_read_unlock();
+ return 0;
+ } else {
+ task_unlock(p);
+ continue;
+ }
}
oom_score_adj = p->signal->oom_score_adj;
if (oom_score_adj < min_score_adj) {
--
1.7.9.5
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