Fix a deadlock in d-channel handling in chan_zap.

This deadlock was introduced by the fix to ensure that channels are properly
locked when handling channel variables.  There were sections of this code where
the channel pvt was locked before the channel lock, when in fact it _must_ be
the other way around.

(closes issue #11582)
Reported by: bugi


git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.4@94251 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 31 insertions, 2 deletions

diff --git a/channels/chan_zap.c b/channels/chan_zap.c
index 8ed8b3ec2..ee7aa0261 100644
--- a/channels/chan_zap.c
+++ b/channels/chan_zap.c
@@ -8813,6 +8813,9 @@ static void *pri_dchannel(void *vpri)
 							} else {
 								c = zt_new(pri->pvts[chanpos], AST_STATE_RESERVED, 0, SUB_REAL, law, e->ring.ctype);
 							}
+
+							ast_mutex_unlock(&pri->pvts[chanpos]->lock);
+
 							if (!ast_strlen_zero(e->ring.callingsubaddr)) {
 								pbx_builtin_setvar_helper(c, "CALLINGSUBADDR", e->ring.callingsubaddr);
 							}
@@ -8831,8 +8834,10 @@ static void *pri_dchannel(void *vpri)
 							pbx_builtin_setvar_helper(c, "CALLEDTON", calledtonstr);
 							if (e->ring.redirectingreason >= 0)
 								pbx_builtin_setvar_helper(c, "PRIREDIRECTREASON", redirectingreason2str(e->ring.redirectingreason));
-							
+						
+							ast_mutex_lock(&pri->pvts[chanpos]->lock);
 							ast_mutex_lock(&pri->lock);
+
 							pthread_attr_init(&attr);
 							pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 							if (c && !ast_pthread_create(&threadid, &attr, ss_thread, c)) {
@@ -8855,9 +8860,11 @@ static void *pri_dchannel(void *vpri)
 							ast_mutex_unlock(&pri->lock);
 							/* Release PRI lock while we create the channel */
 							c = zt_new(pri->pvts[chanpos], AST_STATE_RING, 1, SUB_REAL, law, e->ring.ctype);
-							ast_mutex_lock(&pri->lock);
 							if (c) {
 								char calledtonstr[10];
+
+								ast_mutex_unlock(&pri->pvts[chanpos]->lock);
+
 								if (e->ring.ani2 >= 0) {
 									snprintf(ani2str, 5, "%d", e->ring.ani2);
 									pbx_builtin_setvar_helper(c, "ANI2", ani2str);
@@ -8874,12 +8881,19 @@ static void *pri_dchannel(void *vpri)
 							
 								snprintf(calledtonstr, sizeof(calledtonstr)-1, "%d", e->ring.calledplan);
 								pbx_builtin_setvar_helper(c, "CALLEDTON", calledtonstr);
+
+								ast_mutex_lock(&pri->pvts[chanpos]->lock);
+								ast_mutex_lock(&pri->lock);
+
 								if (option_verbose > 2)
 									ast_verbose(VERBOSE_PREFIX_3 "Accepting call from '%s' to '%s' on channel %d/%d, span %d\n",
 										plancallingnum, pri->pvts[chanpos]->exten, 
 											pri->pvts[chanpos]->logicalspan, pri->pvts[chanpos]->prioffset, pri->span);
 								zt_enable_ec(pri->pvts[chanpos]);
 							} else {
+
+								ast_mutex_lock(&pri->lock);
+
 								ast_log(LOG_WARNING, "Unable to start PBX on channel %d/%d, span %d\n", 
 									pri->pvts[chanpos]->logicalspan, pri->pvts[chanpos]->prioffset, pri->span);
 								pri_hangup(pri->pri, e->ring.call, PRI_CAUSE_SWITCH_CONGESTION);
@@ -8938,7 +8952,10 @@ static void *pri_dchannel(void *vpri)
 
 #ifdef SUPPORT_USERUSER
 						if (!ast_strlen_zero(e->ringing.useruserinfo)) {
+							struct ast_channel *owner = pri->pvts[chanpos]->owner;
+							ast_mutex_unlock(&pri->pvts[chanpos]->lock);
 							pbx_builtin_setvar_helper(pri->pvts[chanpos]->owner, "USERUSERINFO", e->ringing.useruserinfo);
+							ast_mutex_lock(&pri->pvts[chanpos]->lock);
 						}
 #endif
 
@@ -9093,7 +9110,10 @@ static void *pri_dchannel(void *vpri)
 
 #ifdef SUPPORT_USERUSER
 						if (!ast_strlen_zero(e->answer.useruserinfo)) {
+							struct ast_channel *owner = pri->pvts[chanpos]->owner;
+							ast_mutex_unlock(&pri->pvts[chanpos]->lock);
 							pbx_builtin_setvar_helper(pri->pvts[chanpos]->owner, "USERUSERINFO", e->answer.useruserinfo);
+							ast_mutex_lock(&pri->pvts[chanpos]->lock);
 						}
 #endif
 
@@ -9159,7 +9179,10 @@ static void *pri_dchannel(void *vpri)
 
 #ifdef SUPPORT_USERUSER
 						if (pri->pvts[chanpos]->owner && !ast_strlen_zero(e->hangup.useruserinfo)) {
+							struct ast_channel *owner = pri->pvts[chanpos]->owner;
+							ast_mutex_unlock(&pri->pvts[chanpos]->lock);
 							pbx_builtin_setvar_helper(pri->pvts[chanpos]->owner, "USERUSERINFO", e->hangup.useruserinfo);
+							ast_mutex_lock(&pri->pvts[chanpos]->lock);
 						}
 #endif
 
@@ -9225,7 +9248,10 @@ static void *pri_dchannel(void *vpri)
 
 #ifdef SUPPORT_USERUSER
 						if (!ast_strlen_zero(e->hangup.useruserinfo)) {
+							struct ast_channel *owner = pri->pvts[chanpos]->owner;
+							ast_mutex_unlock(&pri->pvts[chanpos]->lock);
 							pbx_builtin_setvar_helper(pri->pvts[chanpos]->owner, "USERUSERINFO", e->hangup.useruserinfo);
+							ast_mutex_lock(&pri->pvts[chanpos]->lock);
 						}
 #endif
 
@@ -9253,7 +9279,10 @@ static void *pri_dchannel(void *vpri)
 
 #ifdef SUPPORT_USERUSER
 						if (!ast_strlen_zero(e->hangup.useruserinfo)) {
+							struct ast_channel *owner = pri->pvts[chanpos]->owner;
+							ast_mutex_unlock(&pri->pvts[chanpos]->lock);
 							pbx_builtin_setvar_helper(pri->pvts[chanpos]->owner, "USERUSERINFO", e->hangup.useruserinfo);
+							ast_mutex_lock(&pri->pvts[chanpos]->lock);
 						}
 #endif