Fix a deadlock that could occur when setting rtp stats on SIP calls.

(closes issue #15143)
Reported by: cristiandimache
Patches:
      15143.patch uploaded by mmichelson (license 60)
Tested by: cristiandimache

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@199588 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index c079e5900c2324c4269328b040561d9269c16510..b5ac173bae31d4ab3d5161d5103aef65ffec6237 100644 (file)
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -5933,6 +5933,17 @@ static int sip_hangup(struct ast_channel *ast)
                                struct ast_channel *bridge = ast_bridged_channel(oldowner);
                                char quality_buf[AST_MAX_USER_FIELD], *quality;
 
+                               /* We need to get the lock on bridge because ast_rtp_instance_set_stats_vars will attempt
+                                * to lock the bridge. This may get hairy...
+                                */
+                               while (bridge && ast_channel_trylock(bridge)) {
+                                       sip_pvt_unlock(p);
+                                       do {
+                                               CHANNEL_DEADLOCK_AVOIDANCE(oldowner);
+                                       } while (sip_pvt_trylock(p));
+                                       bridge = ast_bridged_channel(oldowner);
+                               }
+
                                if (p->rtp) {
                                        ast_rtp_instance_set_stats_vars(oldowner, p->rtp);
                                }
@@ -5943,6 +5954,7 @@ static int sip_hangup(struct ast_channel *ast)
                                        if (IS_SIP_TECH(bridge->tech) && q && q->rtp) {
                                                ast_rtp_instance_set_stats_vars(bridge, q->rtp);
                                        }
+                                       ast_channel_unlock(bridge);
                                }
 
                                if (p->do_history || oldowner) {
@@ -21061,7 +21073,22 @@ static int handle_request_bye(struct sip_pvt *p, struct sip_request *req)
        /* Get RTCP quality before end of call */
        if (p->do_history || p->owner) {
                char quality_buf[AST_MAX_USER_FIELD], *quality;
-               struct ast_channel *bridge = p->owner ? ast_bridged_channel(p->owner) : NULL;
+               struct ast_channel *bridge = p->owner ? ast_bridged_channel(p->owner) : NULL;  
+
+               /* We need to get the lock on bridge because ast_rtp_instance_set_stats_vars will attempt
+                * to lock the bridge. This may get hairy...
+                */
+               while (bridge && ast_channel_trylock(bridge)) {
+                       ast_channel_unlock(p->owner);
+                       do {
+                               /* Can't use DEADLOCK_AVOIDANCE since p is an ao2 object */
+                               sip_pvt_unlock(p);
+                               usleep(1);
+                               sip_pvt_lock(p);
+                       } while (p->owner && ast_channel_trylock(p->owner));
+                       bridge = p->owner ? ast_bridged_channel(p->owner) : NULL;
+               }
+
 
                if (p->rtp && (quality = ast_rtp_instance_get_quality(p->rtp, AST_RTP_INSTANCE_STAT_FIELD_QUALITY, quality_buf, sizeof(quality_buf)))) {
                        if (p->do_history) {
@@ -21090,6 +21117,7 @@ static int handle_request_bye(struct sip_pvt *p, struct sip_request *req)
                        if (IS_SIP_TECH(bridge->tech) && q && q->rtp) {
                                ast_rtp_instance_set_stats_vars(bridge, q->rtp);
                        }
+                       ast_channel_unlock(bridge);
                }
 
                if (p->vrtp && (quality = ast_rtp_instance_get_quality(p->vrtp, AST_RTP_INSTANCE_STAT_FIELD_QUALITY, quality_buf, sizeof(quality_buf)))) {