From 999767beb1b4a10eabf90e6017e496536cf4db0b Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Sun, 21 Oct 2012 01:30:06 +0900 Subject: [PATCH 1/2] workqueue: trivial fix for return statement in work_busy() Return type of work_busy() is unsigned int. There is return statement returning boolean value, 'false' in work_busy(). It is not problem, because 'false' may be treated '0'. However, fixing it would make code robust. Signed-off-by: Joonsoo Kim Signed-off-by: Tejun Heo --- kernel/workqueue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 084aa47bac8..26f5d16aef6 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -3485,7 +3485,7 @@ unsigned int work_busy(struct work_struct *work) unsigned int ret = 0; if (!gcwq) - return false; + return 0; spin_lock_irqsave(&gcwq->lock, flags); From 3657600040a7279e52252af3f9d7e253f4f49ef0 Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Fri, 26 Oct 2012 23:03:49 +0900 Subject: [PATCH 2/2] workqueue: add WARN_ON_ONCE() on CPU number to wq_worker_waking_up() Recently, workqueue code has gone through some changes and we found some bugs related to concurrency management operations happening on the wrong CPU. When a worker is concurrency managed (!WORKER_NOT_RUNNIG), it should be bound to its associated cpu and woken up to that cpu. Add WARN_ON_ONCE() to verify this. Signed-off-by: Joonsoo Kim Signed-off-by: Tejun Heo --- kernel/workqueue.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 26f5d16aef6..ae9a05603e0 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -739,8 +739,10 @@ void wq_worker_waking_up(struct task_struct *task, unsigned int cpu) { struct worker *worker = kthread_data(task); - if (!(worker->flags & WORKER_NOT_RUNNING)) + if (!(worker->flags & WORKER_NOT_RUNNING)) { + WARN_ON_ONCE(worker->pool->gcwq->cpu != cpu); atomic_inc(get_pool_nr_running(worker->pool)); + } } /**