Commit 2b0fd9a5 authored by Steven Rostedt (Google)'s avatar Steven Rostedt (Google)
Browse files

tracing: Wake up waiters when tracing is disabled 



When tracing is disabled, there's no reason that waiters should stay
waiting, wake them up, otherwise tasks get stuck when they should be
flushing the buffers.

Cc: stable@vger.kernel.org
Fixes: e30f53aa ("tracing: Do not busy wait in buffer splice")
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 01b2a521

kernel/trace/trace.c

+6 −0
Original line number Diff line number Diff line
@@ -8334,6 +8334,10 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, 
		if (ret)

			goto out;



		/* No need to wait after waking up when tracing is off */

		if (!tracer_tracing_is_on(iter->tr))

			goto out;



		/* Make sure we see the new wait_index */

		smp_rmb();

		if (wait_index != iter->wait_index)
@@ -9065,6 +9069,8 @@ rb_simple_write(struct file *filp, const char __user *ubuf, 
			tracer_tracing_off(tr);

			if (tr->current_trace->stop)

				tr->current_trace->stop(tr);

			/* Wake up any waiters */

			ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS);

		}

		mutex_unlock(&trace_types_lock);

	}