Properly avoid a collision with iax2_hangup (issue #8115 reported by vazir)

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@44759 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_iax2.c b/channels/chan_iax2.c
index 1a299675c6257ab7145162b0bbede1c1abb0c111..1b6b62db2b62f0347d95daf7163e6021446291aa 100644 (file)
--- a/channels/chan_iax2.c
+++ b/channels/chan_iax2.c
@@ -1688,13 +1688,10 @@ static void iax2_destroy_helper(struct chan_iax2_pvt *pvt)
 static int iax2_predestroy(int callno)
 {
        struct ast_channel *c;
-       struct chan_iax2_pvt *pvt;
-       ast_mutex_lock(&iaxsl[callno]);
-       pvt = iaxs[callno];
-       if (!pvt) {
-               ast_mutex_unlock(&iaxsl[callno]);
+       struct chan_iax2_pvt *pvt = iaxs[callno];
+
+       if (!pvt)
                return -1;
-       }
        if (!ast_test_flag(pvt, IAX_ALREADYGONE)) {
                iax2_destroy_helper(pvt);
                ast_set_flag(pvt, IAX_ALREADYGONE);     
@@ -1708,19 +1705,16 @@ static int iax2_predestroy(int callno)
                ast_atomic_fetchadd_int(&usecnt, -1);
                ast_update_use_count();
        }
-       ast_mutex_unlock(&iaxsl[callno]);
        return 0;
 }
 
 static void iax2_destroy(int callno)
 {
-       struct chan_iax2_pvt *pvt;
+       struct chan_iax2_pvt *pvt = iaxs[callno];
        struct iax_frame *cur;
        struct ast_channel *owner;
 
 retry:
-       ast_mutex_lock(&iaxsl[callno]);
-       pvt = iaxs[callno];
        gettimeofday(&lastused[callno], NULL);
        
        owner = pvt ? pvt->owner : NULL;
@@ -1730,6 +1724,7 @@ retry:
                        ast_log(LOG_NOTICE, "Avoiding IAX destroy deadlock\n");
                        ast_mutex_unlock(&iaxsl[callno]);
                        usleep(1);
+                       ast_mutex_lock(&iaxsl[callno]);
                        goto retry;
                }
        }
@@ -1774,7 +1769,6 @@ retry:
        if (owner) {
                ast_mutex_unlock(&owner->lock);
        }
-       ast_mutex_unlock(&iaxsl[callno]);
        if (callno & 0x4000)
                update_max_trunk();
 }