Commit cef572ad authored by Li Bin's avatar Li Bin Committed by Tejun Heo
Browse files

workqueue: Fix NULL pointer dereference

When queue_work() is used in irq (not in task context), there is
a potential case that trigger NULL pointer dereference.
	|-worker->current_pwq = pwq
 	|-worker->current_pwq = NULL

				//interrupt here
						//assuming that the wq is draining
							//Here, 'current' is the interrupted worker!
								|-current->current_pwq is NULL here!

Avoid it by checking for task context in current_wq_worker(), and
if not in task context, we shouldn't use the 'current' to check the
Reported-by: default avatarXiaofei Tan <>
Signed-off-by: default avatarLi Bin <>
Reviewed-by: default avatarLai Jiangshan <>
Signed-off-by: default avatarTejun Heo <>
Fixes: 8d03ecfe ("workqueue: reimplement is_chained_work() using current_wq_worker()")
Cc: # v3.9+
parent 692b4825
......@@ -9,6 +9,7 @@
#include <linux/workqueue.h>
#include <linux/kthread.h>
#include <linux/preempt.h>
struct worker_pool;
......@@ -59,7 +60,7 @@ struct worker {
static inline struct worker *current_wq_worker(void)
if (current->flags & PF_WQ_WORKER)
if (in_task() && (current->flags & PF_WQ_WORKER))
return kthread_data(current);
return NULL;
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