From d3904a21c4b8c21c510ec645db87488ca1d54387 Mon Sep 17 00:00:00 2001
From: Tilghman Lesher <tilghman@meg.abyt.es>
Date: Fri, 28 Sep 2007 05:37:16 +0000
Subject: [PATCH] Merged revisions 84049 via svnmerge from
https://origsvn.digium.com/svn/asterisk/branches/1.4
........
r84049 | tilghman | 2007-09-28 00:30:22 -0500 (Fri, 28 Sep 2007) | 3 lines
Avoid a deadlock with ALL of the locks in the masquerade function, not just the
pairs of channels. (Closes issue #10406)
........
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@84050 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
main/channel.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/main/channel.c b/main/channel.c
index d8a137ec00..e11afe9d47 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -3333,7 +3333,11 @@ int ast_channel_make_compatible(struct ast_channel *chan, struct ast_channel *pe
int ast_channel_masquerade(struct ast_channel *original, struct ast_channel *clone)
{
int res = -1;
- struct ast_channel *final_orig = original, *final_clone = clone;
+ struct ast_channel *final_orig, *final_clone;
+
+retrymasq:
+ final_orig = original;
+ final_clone = clone;
ast_channel_lock(original);
while (ast_channel_trylock(clone)) {
@@ -3351,11 +3355,19 @@ int ast_channel_masquerade(struct ast_channel *original, struct ast_channel *clo
final_clone = clone->_bridge;
if ((final_orig != original) || (final_clone != clone)) {
- ast_channel_lock(final_orig);
- while (ast_channel_trylock(final_clone)) {
+ /* Lots and lots of deadlock avoidance. The main one we're competing with
+ * is ast_write(), which locks channels recursively, when working with a
+ * proxy channel. */
+ if (ast_channel_trylock(final_orig)) {
+ ast_channel_unlock(clone);
+ ast_channel_unlock(original);
+ goto retrymasq;
+ }
+ if (ast_channel_trylock(final_clone)) {
ast_channel_unlock(final_orig);
- usleep(1);
- ast_channel_lock(final_orig);
+ ast_channel_unlock(clone);
+ ast_channel_unlock(original);
+ goto retrymasq;
}
ast_channel_unlock(clone);
ast_channel_unlock(original);
--
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