Merge tag 'for-5.16/passthrough-flag-2021-10-29' of git://git.kernel.dk/linux-block

[linux-2.6-microblaze.git] / kernel / workqueue.c

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 33a6b4a..1b3eb1e 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4830,8 +4830,16 @@ void show_workqueue_state(void)
 
                for_each_pwq(pwq, wq) {
                        raw_spin_lock_irqsave(&pwq->pool->lock, flags);
-                       if (pwq->nr_active || !list_empty(&pwq->inactive_works))
+                       if (pwq->nr_active || !list_empty(&pwq->inactive_works)) {
+                               /*
+                                * Defer printing to avoid deadlocks in console
+                                * drivers that queue work while holding locks
+                                * also taken in their write paths.
+                                */
+                               printk_deferred_enter();
                                show_pwq(pwq);
+                               printk_deferred_exit();
+                       }
                        raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
                        /*
                         * We could be printing a lot from atomic context, e.g.
@@ -4849,7 +4857,12 @@ void show_workqueue_state(void)
                raw_spin_lock_irqsave(&pool->lock, flags);
                if (pool->nr_workers == pool->nr_idle)
                        goto next_pool;
-
+               /*
+                * Defer printing to avoid deadlocks in console drivers that
+                * queue work while holding locks also taken in their write
+                * paths.
+                */
+               printk_deferred_enter();
                pr_info("pool %d:", pool->id);
                pr_cont_pool_info(pool);
                pr_cont(" hung=%us workers=%d",
@@ -4864,6 +4877,7 @@ void show_workqueue_state(void)
                        first = false;
                }
                pr_cont("\n");
+               printk_deferred_exit();
        next_pool:
                raw_spin_unlock_irqrestore(&pool->lock, flags);
                /*