[Asterisk-code-review] Fix deadlock handling subscribe req during res parking reload (asterisk[certified/13.18])

[Giuseppe Sucameli]

Giuseppe Sucameli has uploaded this change for review. ( https://gerrit.asterisk.org/10701


Change subject: Fix deadlock handling subscribe req during res_parking reload
......................................................................

Fix deadlock handling subscribe req during res_parking reload

Split destroy_hint method to separate hint removal and extension hint
state changed callback, the latter now called via stasis.
This avoids deadlock between res_parking reload that is removing the
parking lot and the related hint and subscribe requests coming for the
same parking lot.

ASTERISK-28173

Change-Id: I5b03c3455b3b12b6f83cea4cc34f4b4b20444f7e
---
M main/pbx.c
1 file changed, 30 insertions(+), 29 deletions(-)



  git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/01/10701/1

diff --git a/main/pbx.c b/main/pbx.c
index 173b62e..08805cf 100644
--- a/main/pbx.c
+++ b/main/pbx.c
@@ -3311,8 +3311,31 @@
 
 	ao2_lock(hint);
 	if (!hint->exten) {
-		/* The extension has already been destroyed */
+		/* The extension has already been destroyed,
+		 * notify extension deactivation
+		 */
+		if (!hint->callbacks) {
+			ao2_unlock(hint);
+			return;
+		}
+
+		ast_copy_string(context_name, hint->context_name, sizeof(context_name));
+		ast_copy_string(exten_name, hint->exten_name, sizeof(exten_name));
+
+		hint->laststate = AST_EXTENSION_DEACTIVATED;
 		ao2_unlock(hint);
+
+	        cb_iter = ao2_iterator_init(hint->callbacks, 0);
+	        for (; (state_cb = ao2_iterator_next(&cb_iter)); ao2_ref(state_cb, -1)) {
+			execute_state_callback(state_cb->change_cb,
+				context_name,
+				exten_name,
+				state_cb->data,
+				AST_HINT_UPDATE_DEVICE,
+				hint,
+				NULL);
+		}
+		ao2_iterator_destroy(&cb_iter);
 		return;
 	}
 
@@ -3808,31 +3831,7 @@
 	int i;
 
 	if (hint->callbacks) {
-		struct ast_state_cb *state_cb;
-		const char *context_name;
-		const char *exten_name;
-
-		if (hint->exten) {
-			context_name = ast_get_context_name(ast_get_extension_context(hint->exten));
-			exten_name = ast_get_extension_name(hint->exten);
-			hint->exten = NULL;
-		} else {
-			/* The extension has already been destroyed */
-			context_name = hint->context_name;
-			exten_name = hint->exten_name;
-		}
-		hint->laststate = AST_EXTENSION_DEACTIVATED;
-		while ((state_cb = ao2_callback(hint->callbacks, OBJ_UNLINK, NULL, NULL))) {
-			/* Notify with -1 and remove all callbacks */
-			execute_state_callback(state_cb->change_cb,
-				context_name,
-				exten_name,
-				state_cb->data,
-				AST_HINT_UPDATE_DEVICE,
-				hint,
-				NULL);
-			ao2_ref(state_cb, -1);
-		}
+		ao2_callback(hint->callbacks, OBJ_NODATA | OBJ_MULTIPLE | OBJ_UNLINK, NULL, NULL);
 		ao2_ref(hint->callbacks, -1);
 	}
 
@@ -3845,6 +3844,8 @@
 	ast_free(hint->last_presence_message);
 }
 
+static int publish_hint_change(struct ast_hint *hint, struct ast_exten *ne);
+
 /*! \brief Remove hint from extension */
 static int ast_remove_hint(struct ast_exten *e)
 {
@@ -3875,6 +3876,8 @@
 	hint->exten = NULL;
 	ao2_unlock(hint);
 
+	publish_hint_change(hint, e);
+
 	ao2_ref(hint, -1);
 
 	return 0;
@@ -3981,9 +3984,7 @@
 		return -1;
 	}
 
-	/* The message is going to be published to two topics so the hint needs two refs */
-	if (!(message = stasis_message_create(hint_change_message_type(), ao2_bump(hint)))) {
-		ao2_ref(hint, -1);
+	if (!(message = stasis_message_create(hint_change_message_type(), hint))) {
 		return -1;
 	}
 

-- 
To view, visit https://gerrit.asterisk.org/10701
To unsubscribe, or for help writing mail filters, visit https://gerrit.asterisk.org/settings

Gerrit-Project: asterisk
Gerrit-Branch: certified/13.18
Gerrit-MessageType: newchange
Gerrit-Change-Id: I5b03c3455b3b12b6f83cea4cc34f4b4b20444f7e
Gerrit-Change-Number: 10701
Gerrit-PatchSet: 1
Gerrit-Owner: Giuseppe Sucameli <sucameli at netresults.it>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.digium.com/pipermail/asterisk-code-review/attachments/20181119/b9194ffa/attachment-0001.html>