output_thread: fix race condition after CANCEL command

Clear the notification before finishing the CANCEL command, so the notify_wait() after that will always wait for the right notification, sent by audio_output_all_cancel().

output_thread: fix race condition after CANCEL command
64dacd17 · Max Kellermann · 625e4755 · 64dacd17 · 64dacd17
Commit 64dacd17 authored Aug 19, 2010 by Max Kellermann
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NEWS NEWS +1 -0

output_thread.c src/output_thread.c +10 -0

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--- a/NEWS
+++ b/NEWS
 ver 0.15.13 (2010/??/??)
+* output_thread: fix race condition after CANCEL command


 ver 0.15.12 (2010/07/20)

--- a/src/output_thread.c
+++ b/src/output_thread.c
@@ -268,6 +268,16 @@ static gpointer audio_output_task(gpointer arg)
 			ao->chunk = NULL;
 			if (ao->open)
 				ao_plugin_cancel(ao->plugin, ao->data);
+
+			/* we must clear the notification now, because
+			   the notify_wait() call below must wait
+			   until audio_output_all_cancel() has cleared
+			   the pipe; if another notification happens
+			   to be still pending, we get a race
+			   condition with a crash or an assertion
+			   failure */
+			notify_clear(&ao->notify);
+
 			ao_command_finished(ao);

 			/* the player thread will now clear our music