Fix a crash if the channel becomes NULL while attempting to lock it.

(closes issue #12039)
Reported by: danpwi

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@103904 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_local.c b/channels/chan_local.c
index 9ea0018b2175931f13f426f82acc6e2cd293fcd2..5a8d6f002d78b0857ac9b8361e7c632796a22c71 100644 (file)
--- a/channels/chan_local.c
+++ b/channels/chan_local.c
@@ -503,13 +503,15 @@ static int local_hangup(struct ast_channel *ast)
                const char *status = pbx_builtin_getvar_helper(p->chan, "DIALSTATUS");
                if ((status) && (p->owner)) {
                        /* Deadlock avoidance */
-                       while (ast_channel_trylock(p->owner)) {
+                       while (p->owner && ast_channel_trylock(p->owner)) {
                                ast_mutex_unlock(&p->lock);
                                usleep(1);
                                ast_mutex_lock(&p->lock);
                        }
-                       pbx_builtin_setvar_helper(p->owner, "CHANLOCALSTATUS", status);
-                       ast_channel_unlock(p->owner);
+                       if (p->owner) {
+                               pbx_builtin_setvar_helper(p->owner, "CHANLOCALSTATUS", status);
+                               ast_channel_unlock(p->owner);
+                       }
                }
                p->chan = NULL;
                ast_clear_flag(p, LOCAL_LAUNCHED_PBX);