[PATCH 1/2 wq/for-3.9] workqueue: fix is_chained_work() regression

From: Tejun Heo
Date: Wed Feb 13 2013 - 22:26:53 EST


c9e7cf273f ("workqueue: move busy_hash from global_cwq to
worker_pool") incorrectly converted is_chained_work() to use
get_gcwq() inside for_each_gcwq_cpu() while removing get_gcwq().

As cwq might not exist for all possible workqueue CPUs, @cwq can be
NULL and the following cwq deferences can lead to oops.

Fix it by using for_each_cwq_cpu() instead, which is the better one to
use anyway as we only need to check pools that the wq is associated
with.

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
kernel/workqueue.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1167,7 +1167,7 @@ static bool is_chained_work(struct workq
unsigned long flags;
unsigned int cpu;

- for_each_wq_cpu(cpu) {
+ for_each_cwq_cpu(cpu, wq) {
struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
struct worker_pool *pool = cwq->pool;
struct worker *worker;
--
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