Avoid a deadlock in chanspy, just in case the spyee is masqueraded and chanspy_ds_cha...

(closes issue #15965)
Reported by: atis
Patches:
      chanspy-deadlock-fix1.diff uploaded by mnicholson (license 96)
Tested by: atis

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.6.1@220938 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/apps/app_chanspy.c b/apps/app_chanspy.c
index 7317e3578530afbd8e611727c4ebfadc56133825..0932a842d15577379c1f2cdad2fd00bc2f771637 100644 (file)
--- a/apps/app_chanspy.c
+++ b/apps/app_chanspy.c
@@ -337,9 +337,10 @@ static int channel_spy(struct ast_channel *chan, struct chanspy_ds *spyee_chansp
        ast_channel_unlock(chan);
 
        ast_mutex_lock(&spyee_chanspy_ds->lock);
-       if (spyee_chanspy_ds->chan) {
-               spyee = spyee_chanspy_ds->chan;
-               ast_channel_lock(spyee);
+       while ((spyee = spyee_chanspy_ds->chan) && ast_channel_trylock(spyee)) {
+               /* avoid a deadlock here, just in case spyee is masqueraded and
+                * chanspy_ds_chan_fixup() is called with the channel locked */
+               DEADLOCK_AVOIDANCE(&spyee_chanspy_ds->lock);
        }
        ast_mutex_unlock(&spyee_chanspy_ds->lock);