#! /bin/sh /usr/share/dpatch/dpatch-run
## local_queue_frame_livelock.dpatch by Philipp Berndt <philipp.berndt@smeet.de>
##
## All lines beginning with `## DP:' are a description of the patch.
## DP: Prevent system lock-up by limiting number of locking attempts

@DPATCH@
diff -urNad asterisk-1.2.13~dfsg~/channels/chan_local.c asterisk-1.2.13~dfsg/channels/chan_local.c
--- asterisk-1.2.13~dfsg~/channels/chan_local.c	2006-09-08 06:37:07.000000000 +0200
+++ asterisk-1.2.13~dfsg/channels/chan_local.c	2008-02-11 13:03:08.000000000 +0100
@@ -117,6 +117,11 @@
 static int local_queue_frame(struct local_pvt *p, int isoutbound, struct ast_frame *f, struct ast_channel *us)
 {
 	struct ast_channel *other;
+	int retrycnt = 0;
+	struct timeval t1, t2;
+	int diff;
+	t1 = ast_tvnow();
+
 retrylock:		
 	/* Recalculate outbound channel */
 	if (isoutbound) {
@@ -139,6 +144,11 @@
 		return 0;
 	}
 	if (ast_mutex_trylock(&other->lock)) {
+		if (other->_softhangup) {
+		    ast_log(LOG_DEBUG, "local_queue_frame() us=%s giving up waiting for lock on other since it has _softhangup set\n", us?us->name:"null");
+		    p->glaredetect = 0;
+		    return 0;
+		}
 		/* Failed to lock.  Release main lock and try again */
 		ast_mutex_unlock(&p->lock);
 		if (us) {
@@ -154,8 +164,17 @@
 		if (us)
 			ast_mutex_lock(&us->lock);
 		ast_mutex_lock(&p->lock);
+		if (++retrycnt > 1000)
+		{
+		     ast_log(LOG_WARNING, "local_queue_frame() us=%s giving up waiting for lock on other\n", us?us->name:"null");
+		     p->glaredetect = 0;
+		     return 0;
+		}
 		goto retrylock;
 	}
+       t2 = ast_tvnow();
+	if ( (diff = ast_tvdiff_ms(t2, t1)) > 20 )
+		ast_log( LOG_WARNING, "local_queue_frame() aquire lock took %d ms in %d attempts\n", diff, retrycnt);
 	ast_queue_frame(other, f);
 	ast_mutex_unlock(&other->lock);
 	p->glaredetect = 0;