Add proper deadlock avoidance.

(closes issue #12914)
 Reported by: ozan
 Patches:
       20080625__bug12914.diff.txt uploaded by Corydon76 (license 14)
 Tested by: ozan

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@125740 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_local.c b/channels/chan_local.c
index 294fbffca08af211ad127d572b2623648666392c..783e973e03c1ed350f55213b12bc9e879e2b0a9b 100644 (file)
--- a/channels/chan_local.c
+++ b/channels/chan_local.c
@@ -186,13 +186,15 @@ static int local_queue_frame(struct local_pvt *p, int isoutbound, struct ast_fra
        while (other && ast_channel_trylock(other)) {
                ast_mutex_unlock(&p->lock);
                if (us && us_locked) {
-                       ast_channel_unlock(us);
-               }
-               usleep(1);
-               if (us && us_locked) {
-                       ast_channel_lock(us);
+                       do {
+                               ast_channel_unlock(us);
+                               usleep(1);
+                               ast_channel_lock(us);
+                       } while (ast_mutex_trylock(&p->lock));
+               } else {
+                       usleep(1);
+                       ast_mutex_lock(&p->lock);
                }
-               ast_mutex_lock(&p->lock);
                other = isoutbound ? p->owner : p->chan;
        }
 
@@ -510,7 +512,12 @@ static int local_hangup(struct ast_channel *ast)
        if (!p)
                return -1;
 
-       ast_mutex_lock(&p->lock);
+       while (ast_mutex_trylock(&p->lock)) {
+               ast_channel_unlock(ast);
+               usleep(1);
+               ast_channel_lock(ast);
+       }
+
        isoutbound = IS_OUTBOUND(ast, p);
        if (isoutbound) {
                const char *status = pbx_builtin_getvar_helper(p->chan, "DIALSTATUS");