1 files changed, 12 insertions, 0 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 6ba0c6054224..8edc87185427 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1916,6 +1916,12 @@ static void send_mayday(struct work_struct *work)
 
         /* mayday mayday mayday */
         if (list_empty(&pwq->mayday_node)) {
+                /*
+                 * If @pwq is for an unbound wq, its base ref may be put at
+                 * any time due to an attribute change.  Pin @pwq until the
+                 * rescuer is done with it.
+                 */
+                get_pwq(pwq);
                 list_add_tail(&pwq->mayday_node, &wq->maydays);
                 wake_up_process(wq->rescuer->task);
         }
@@ -2450,6 +2456,12 @@ repeat:
                 process_scheduled_works(rescuer);
 
                 /*
+                 * Put the reference grabbed by send_mayday().  @pool won't
+                 * go away while we're holding its lock.
+                 */
+                put_pwq(pwq);
+
+                /*
                  * Leave this pool.  If keep_working() is %true, notify a
                  * regular worker; otherwise, we end up with 0 concurrency
                  * and stalling the execution.