Commit ec0bbc5e authored by Steven Rostedt (Google)'s avatar Steven Rostedt (Google)
Browse files

ring-buffer: Check pending waiters when doing wake ups as well 

The wake up waiters only checks the "wakeup_full" variable and not the
"full_waiters_pending". The full_waiters_pending is set when a waiter is
added to the wait queue. The wakeup_full is only set when an event is
triggered, and it clears the full_waiters_pending to avoid multiple calls
to irq_work_queue().

The irq_work callback really needs to check both wakeup_full as well as
full_waiters_pending such that this code can be used to wake up waiters
when a file is closed that represents the ring buffer and the waiters need
to be woken up.

Link: https://lkml.kernel.org/r/20220927231824.209460321@goodmis.org



Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 15693458 ("tracing/ring-buffer: Move poll wake ups into ring buffer code")
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 3b19d614

kernel/trace/ring_buffer.c

+2 −1
Original line number Diff line number Diff line
@@ -917,8 +917,9 @@ static void rb_wake_up_waiters(struct irq_work *work) 
	struct rb_irq_work *rbwork = container_of(work, struct rb_irq_work, work);



	wake_up_all(&rbwork->waiters);

	if (rbwork->wakeup_full) {

	if (rbwork->full_waiters_pending || rbwork->wakeup_full) {

		rbwork->wakeup_full = false;

		rbwork->full_waiters_pending = false;

		wake_up_all(&rbwork->full_waiters);

	}

}