Merged revisions 113065 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.4

........
r113065 | mmichelson | 2008-04-07 11:08:45 -0500 (Mon, 07 Apr 2008) | 13 lines

This fix prevents a deadlock that was experienced in chan_local. There was
deadlock prevention in place in chan_local, but it would not work in a specific
case because the channel was recursively locked. By unlocking the channel prior
to calling the generator's generate callback in ast_read_generator_actions(), we
prevent the recursive locking, and therefore the deadlock.

(closes issue #12307)
Reported by: callguy
Patches:
      12307.patch uploaded by putnopvut (license 60)
Tested by: callguy


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git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@113066 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/channel.c

@@ -2273,7 +2273,17 @@ static void ast_read_generator_actions(struct ast_channel *chan, struct ast_fram
 		} else {
 			samples = f->samples;
 		}
+		/* This unlock is here based on two assumptions that hold true at this point in the
+		 * code. 1) this function is only called from within __ast_read() and 2) all generators
+		 * call ast_write() in their generate callback.
+		 *
+		 * The reason this is added is so that when ast_write is called, the lock that occurs 
+		 * there will not recursively lock the channel. Doing this will cause intended deadlock 
+		 * avoidance not to work in deeper functions
+		 */
+		ast_channel_unlock(chan);
 		res = chan->generator->generate(chan, tmp, f->datalen, samples);
+		ast_channel_lock(chan);
 		chan->generatordata = tmp;
 		if (res) {
 			if (option_debug > 1)