From 970b84946e4bb57957b8015cacb92c1c0e8797a8 Mon Sep 17 00:00:00 2001
From: "Joshua C. Colp" <jcolp@sangoma.com>
Date: Fri, 19 Mar 2021 10:52:08 -0300
Subject: [PATCH] core_unreal: Fix deadlock with T.38 control frames.
When using the ast_unreal_lock_all function no channel
locks can be held before calling it.
This change unlocks the channel that indicate was
called on before doing so and then relocks it afterwards.
ASTERISK-29035
Change-Id: Id65016201b5f9c9519a216e250f9101c629e19e9
---
main/core_unreal.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/main/core_unreal.c b/main/core_unreal.c
index 5adc90d2f7..a79fca417f 100644
--- a/main/core_unreal.c
+++ b/main/core_unreal.c
@@ -710,6 +710,7 @@ int ast_unreal_indicate(struct ast_channel *ast, int condition, const void *data
* signaling and we need to be sure that the locking order is the same to prevent possible
* deadlocks.
*/
+ ast_channel_unlock(ast);
ast_unreal_lock_all(p, &chan, &owner);
if (owner) {
@@ -726,12 +727,14 @@ int ast_unreal_indicate(struct ast_channel *ast, int condition, const void *data
}
ao2_unlock(p);
+ ast_channel_lock(ast);
} else if (parameters->request_response == AST_T38_TERMINATED) {
/*
* Lock both parts of the local channel so we can restore their topologies to the original.
* The topology should be on the unreal_pvt structure, with a ref that we can steal. Same
* conditions as above.
*/
+ ast_channel_unlock(ast);
ast_unreal_lock_all(p, &chan, &owner);
if (owner) {
@@ -745,6 +748,7 @@ int ast_unreal_indicate(struct ast_channel *ast, int condition, const void *data
}
ao2_unlock(p);
+ ast_channel_lock(ast);
}
/*
--
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