ast_do_masquerade. Keep channels ao2_container locked while unlink and linking channels.

Previously, Masquerade would unlock 'original' and 'clonechan' and allow another masq thread to run.
End result would be corrupted memory, and the frequent report 'Bad Magic Number'.

(closes issue #17801,#17710)
Reported by: notthematrix
Patches:
      Based on bug17801.diff1.txt uploaded by alecdavis (license 585)
Tested by: alecdavis

Review: https://reviewboard.asterisk.org/r/928

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@287661 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/main/channel.c b/main/channel.c
index 9954d6613c5e8148805cbaa904297f1c013541e3..7c6a98a9034a15982e04eb569fd5ac2c63a8d127 100644 (file)
--- a/main/channel.c
+++ b/main/channel.c
@@ -5984,9 +5984,6 @@ int ast_do_masquerade(struct ast_channel *original)
        ao2_unlink(channels, original);
        ao2_unlink(channels, clonechan);
 
-       /* now that both channels are locked and unlinked from the container, it is safe to unlock it */
-       ao2_unlock(channels);
-
        ast_debug(4, "Actually Masquerading %s(%d) into the structure of %s(%d)\n",
                clonechan->name, clonechan->_state, original->name, original->_state);
 
@@ -6269,6 +6266,8 @@ done:
                ao2_link(channels, original);
        }
 
+       ao2_unlock(channels);
+
        return 0;
 }