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-rw-r--r--kernel/workqueue.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index bfeef512f..c0b72dcc0 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3197,7 +3197,16 @@ restart:
#ifdef CONFIG_PREEMPT_RT
static void worker_lock_callback(struct worker_pool *pool)
{
- spin_lock(&pool->cb_lock);
+ /*
+ * SINGLE_DEPTH_NESTING is for a dead pool's bh_worker() running from
+ * drain_dead_softirq_workfn() inside a live pool's bh_worker(). The
+ * unlocked read is stable: the flag is only set while @pool's CPU is
+ * dead, inside a serialized hotplug operation. data_race() as the value
+ * only affects the lockdep annotation and the read can be elided when
+ * lockdep is disabled.
+ */
+ spin_lock_nested(&pool->cb_lock,
+ data_race(pool->flags) & POOL_BH_DRAINING ? SINGLE_DEPTH_NESTING : 0);
}
static void worker_unlock_callback(struct worker_pool *pool)