Index: channels/chan_sip.c
===================================================================
--- channels/chan_sip.c	(revision 92813)
+++ channels/chan_sip.c	(working copy)
@@ -7127,7 +7127,7 @@
 	subscriptiontype = find_subscription_type(p->subscribed);
 	
 	/* Check which device/devices we are watching  and if they are registered */
-	if (ast_get_hint(hint, sizeof(hint), NULL, 0, NULL, p->context, p->exten)) {
+	if (ast_get_hint(hint, sizeof(hint), NULL, 0, NULL, p->context, p->exten) == -1) {
 		char *hint2 = hint, *individual_hint = NULL;
 		int hint_count = 0, unavailable_count = 0;
 
@@ -8767,7 +8767,7 @@
 	/* If this is a subscription we actually just need to see if a hint exists for the extension */
 	if (req->method == SIP_SUBSCRIBE) {
 		char hint[AST_MAX_EXTENSION];
-		return (ast_get_hint(hint, sizeof(hint), NULL, 0, NULL, p->context, p->exten) ? 0 : -1);
+		return (ast_get_hint(hint, sizeof(hint), NULL, 0, NULL, p->context, p->exten) == -1 ? 0 : -1);
 	} else {
 		/* Check the dialplan for the username part of the request URI,
 		   the domain will be stored in the SIPDOMAIN variable
Index: apps/app_dial.c
===================================================================
--- apps/app_dial.c	(revision 92813)
+++ apps/app_dial.c	(working copy)
@@ -374,7 +374,7 @@
 	const char *context = S_OR(chan->macrocontext, chan->context);
 	const char *exten = S_OR(chan->macroexten, chan->exten);
 
-	return ast_get_hint(NULL, 0, name, namelen, chan, context, exten) ? name : "";
+	return ast_get_hint(NULL, 0, name, namelen, chan, context, exten) == -1 ? name : "";
 }
 
 static void senddialevent(struct ast_channel *src, struct ast_channel *dst)
Index: include/asterisk/pbx.h
===================================================================
--- include/asterisk/pbx.h	(revision 92813)
+++ include/asterisk/pbx.h	(working copy)
@@ -313,7 +313,10 @@
  * \param context which context to look in
  * \param exten which extension to get state
  *
- * \return extension state as defined in the ast_extension_states enum
+ * \retval extension state as defined in the ast_extension_states enum
+ * \retval -EAGAIN if a deadlock would have resulted.  You may unlock and
+ * relock all mutexes and try again.
+ * \retval -1 if the extension does not have an associated hint
  */
 int ast_extension_state(struct ast_channel *c, const char *context, const char *exten);
 
@@ -338,6 +341,8 @@
  *
  * \retval -1 on failure
  * \retval ID on success
+ * \retval -EGAIN if a deadlock would have resulted.  You may choose to unlock
+ * and lock all mutexes held before trying again.
  */ 
 int ast_extension_state_add(const char *context, const char *exten, 
 			    ast_state_cb_type callback, void *data);
@@ -366,9 +371,11 @@
  * \param context which context to look in
  * \param exten which extension to search for
  *
- * \return If an extension within the given context with the priority PRIORITY_HINT
- * is found a non zero value will be returned.
- * Otherwise, 0 is returned.
+ * \retval -1, if an extension within the given context with the priority
+ * PRIORITY_HINT is found.
+ * \retval 0, if the hint is not found
+ * \retval -EGAIN if a deadlock would have resulted.  You may choose to unlock
+ * and relock all mutexes held before trying again.
  */
 int ast_get_hint(char *hint, int maxlen, char *name, int maxnamelen, 
 	struct ast_channel *c, const char *context, const char *exten);
Index: main/pbx.c
===================================================================
--- main/pbx.c	(revision 92813)
+++ main/pbx.c	(working copy)
@@ -1189,9 +1189,21 @@
 				}
 			}
 		} else if (!strcmp(var, "HINT")) {
-			s = ast_get_hint(workspace, workspacelen, NULL, 0, c, c->context, c->exten) ? workspace : NULL;
+			int i = 0, ret;
+			while (i++ < 10 && (ret = ast_get_hint(workspace, workspacelen, NULL, 0, c, c->context, c->exten)) == -EAGAIN) {
+				ast_channel_unlock(c);
+				usleep(1);
+				ast_channel_lock(c);
+			}
+			s = ret == -1 ? workspace : NULL;
 		} else if (!strcmp(var, "HINTNAME")) {
-			s = ast_get_hint(NULL, 0, workspace, workspacelen, c, c->context, c->exten) ? workspace : NULL;
+			int i = 0, ret;
+			while (i++ < 10 && (ret = ast_get_hint(NULL, 0, workspace, workspacelen, c, c->context, c->exten)) == -EAGAIN) {
+				ast_channel_unlock(c);
+				usleep(1);
+				ast_channel_lock(c);
+			}
+			s = ret == -1 ? workspace : NULL;
 		} else if (!strcmp(var, "EXTEN")) {
 			s = c->exten;
 		} else if (!strcmp(var, "CONTEXT")) {
@@ -1886,14 +1898,17 @@
 }
 
 /*! \brief  ast_hint_extension: Find hint for given extension in context */
-static struct ast_exten *ast_hint_extension(struct ast_channel *c, const char *context, const char *exten)
+static struct ast_exten *ast_hint_extension(struct ast_channel *c, const char *context, const char *exten, int *err)
 {
-	struct ast_exten *e;
+	struct ast_exten *e = NULL;
 	struct pbx_find_info q = { .stacklen = 0 }; /* the rest is set in pbx_find_context */
 
-	ast_mutex_lock(&conlock);
-	e = pbx_find_extension(c, NULL, &q, context, exten, PRIORITY_HINT, NULL, "", E_MATCH);
-	ast_mutex_unlock(&conlock);
+	if (!ast_mutex_trylock(&conlock)) {
+		e = pbx_find_extension(c, NULL, &q, context, exten, PRIORITY_HINT, NULL, "", E_MATCH);
+		ast_mutex_unlock(&conlock);
+		*err = 0;
+	} else
+		*err = EAGAIN;
 
 	return e;
 }
@@ -1999,10 +2014,15 @@
 int ast_extension_state(struct ast_channel *c, const char *context, const char *exten)
 {
 	struct ast_exten *e;
+	int err = 0;
 
-	e = ast_hint_extension(c, context, exten);	/* Do we have a hint for this extension ? */
-	if (!e)
-		return -1;				/* No hint, return -1 */
+	e = ast_hint_extension(c, context, exten, &err);	/* Do we have a hint for this extension ? */
+	if (!e) {
+		if (err == EAGAIN)
+			return -EAGAIN;
+		else
+			return -1;				/* No hint, return -1 */
+	}
 
 	return ast_extension_state2(e);    		/* Check all devices in the hint */
 }
@@ -2059,6 +2079,7 @@
 	struct ast_hint *hint;
 	struct ast_state_cb *cblist;
 	struct ast_exten *e;
+	int err = 0;
 
 	/* If there's no context and extension:  add callback to statecbs list */
 	if (!context && !exten) {
@@ -2092,9 +2113,12 @@
 		return -1;
 
 	/* This callback type is for only one hint, so get the hint */
-	e = ast_hint_extension(NULL, context, exten);
+	e = ast_hint_extension(NULL, context, exten, &err);
 	if (!e) {
-		return -1;
+		if (err == EAGAIN)
+			return -EAGAIN;
+		else
+			return -1;
 	}
 
 	/* Find the hint in the list of hints */
@@ -2259,7 +2283,8 @@
 /*! \brief  ast_get_hint: Get hint for channel */
 int ast_get_hint(char *hint, int hintsize, char *name, int namesize, struct ast_channel *c, const char *context, const char *exten)
 {
-	struct ast_exten *e = ast_hint_extension(c, context, exten);
+	int err = 0;
+	struct ast_exten *e = ast_hint_extension(c, context, exten, &err);
 
 	if (e) {
 		if (hint)
@@ -2270,7 +2295,8 @@
 				ast_copy_string(name, tmp, namesize);
 		}
 		return -1;
-	}
+	} else if (err == EAGAIN)
+		return -EAGAIN;
 	return 0;
 }
 
@@ -3928,7 +3954,7 @@
 	struct store_hint *this;
 	struct ast_hint *hint;
 	struct ast_exten *exten;
-	int length;
+	int length, err = 0;
 	struct ast_state_cb *thiscb, *prevcb;
 
 	/* it is very important that this function hold the hint list lock _and_ the conlock
@@ -3989,7 +4015,17 @@
 	   cannot be restored
 	*/
 	while ((this = AST_LIST_REMOVE_HEAD(&store, list))) {
-		exten = ast_hint_extension(NULL, this->context, this->exten);
+retry_hint:
+		exten = ast_hint_extension(NULL, this->context, this->exten, &err);
+		if (err) {
+			AST_LIST_UNLOCK(&hints);
+			ast_mutex_unlock(&conlock);
+			usleep(1);
+			ast_mutex_lock(&conlock);
+			AST_LIST_LOCK(&hints);
+			goto retry_hint;
+		}
+
 		/* Find the hint in the list of hints */
 		AST_LIST_TRAVERSE(&hints, hint, list) {
 			if (hint->exten == exten)