[asterisk-commits] irroot: branch 1.8 r330311 - /branches/1.8/main/channel.c

[SVN commits to the Asterisk project]

Author: irroot
Date: Sat Jul 30 10:25:16 2011
New Revision: 330311

URL: http://svnview.digium.com/svn/asterisk?view=rev&rev=330311
Log:
prevent double masqurading channels when one is been hung up and deadlock avoidance is used.

There is a race condition in ast_do_masquerade / ast_hangup (at least)

Reported by me signed off by schmidts with input from David Vossel

Review: https://reviewboard.asterisk.org/r/1323/


Modified:
    branches/1.8/main/channel.c

Modified: branches/1.8/main/channel.c
URL: http://svnview.digium.com/svn/asterisk/branches/1.8/main/channel.c?view=diff&rev=330311&r1=330310&r2=330311
==============================================================================
--- branches/1.8/main/channel.c (original)
+++ branches/1.8/main/channel.c Sat Jul 30 10:25:16 2011
@@ -6320,8 +6320,16 @@
 	 * for deadlock avoidance will not result in any sort of masquerade race condition.
 	 * If masq is called by a different thread while this happens, it will be stuck waiting
 	 * until we unlock the container. */
-	while (ast_channel_trylock(clonechan)) {
+	while ((clonechan = original->masq) && ast_channel_trylock(clonechan)) {
 		CHANNEL_DEADLOCK_AVOIDANCE(original);
+	}
+
+	/* recheck if masq has been done the deadlock avoidance above could cause a double masq
+	 * this is posible with at least ast_hangup*/
+	if (!original->masq) {
+		ast_channel_unlock(original);
+		ao2_unlock(channels);
+		return 0; /* masq already completed by another thread, or never needed to be done to begin with */
 	}
 
 	/* Get any transfer masquerade connected line exchange data. */