diff options
| author | Matthew Jordan <mjordan@digium.com> | 2013-03-26 02:30:10 +0000 |
|---|---|---|
| committer | Matthew Jordan <mjordan@digium.com> | 2013-03-26 02:30:10 +0000 |
| commit | 58ee2b7d11891bfb2de1d0346aa660ceb5cad80d (patch) | |
| tree | 7faf3ab030c5c602a0280bc68b9599018f5c24c2 | |
| parent | ec7de8ed97d9da6588fbc7dffbe6527fb8b9c250 (diff) | |
Resolve deadlock between SIP registration and channel based functions
In r373424, several reentrancy problems in chan_sip were addressed. As a
result, the SIP channel driver is now properly locking the channel driver
private information in certain operations that it wasn't previously. This
exposed two latent problems either in register_verify or by functions called
by register_verify. This includes:
* Holding the private lock while calling sip_send_mwi_to_peer. This can create
a new sip_pvt via sip_alloc, which will obtain the channel container lock.
This is a locking inversion, as any channel related lock must be obtained
prior to obtaining the SIP channel technology private lock.
Note that this issue was already fixed in Asterisk 11.
* Holding the private lock while calling sip_poke_peer. In the same vein as
sip_send_mwi_to_peer, sip_poke_peer can create a new SIP private, causing
the same locking inversion.
Note that this locking inversion typically occured when CLI commands were run
while a SIP REGISTER request was being processed, as many CLI commands (such
as 'sip show channels', 'core show channels', etc.) have to obtain the channel
container lock.
(issue ASTERISK-21068)
Reported by: Nicolas Bouliane
(issue ASTERISK-20550)
Reported by: David Brillert
(issue ASTERISK-21314)
Reported by: Badalian Vyacheslav
(issue ASTERISK-21296)
Reported by: Gabriel Birke
........
Merged revisions 383863 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........
Merged revisions 383878 from http://svn.asterisk.org/svn/asterisk/branches/11
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@383879 65c4cc65-6c06-0410-ace0-fbb531ad65f3
| -rw-r--r-- | channels/chan_sip.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/channels/chan_sip.c b/channels/chan_sip.c index 28e8d4d35..82a8519d0 100644 --- a/channels/chan_sip.c +++ b/channels/chan_sip.c @@ -16131,7 +16131,9 @@ static enum parse_register_result parse_register_contact(struct sip_pvt *pvt, st ast_verb(3, "Registered SIP '%s' at %s\n", peer->name, ast_sockaddr_stringify(&peer->addr)); } + sip_pvt_unlock(pvt); sip_poke_peer(peer, 0); + sip_pvt_lock(pvt); register_peer_exten(peer, 1); /* Save User agent */ @@ -17163,9 +17165,9 @@ static enum check_auth_result register_verify(struct sip_pvt *p, struct ast_sock } if (!res) { if (send_mwi) { - ao2_unlock(p); + sip_pvt_unlock(p); sip_send_mwi_to_peer(peer, 0); - ao2_lock(p); + sip_pvt_lock(p); } else { update_peer_lastmsgssent(peer, -1, 0); } @@ -29611,6 +29613,9 @@ static int sip_poke_noanswer(const void *data) \note This is done with 60 seconds between each ping, unless forced by cli or manager. If peer is unreachable, we check every 10th second by default. +\note Do *not* hold a pvt lock while calling this function. + This function calls sip_alloc, which can cause a deadlock + if another sip_pvt is held. */ static int sip_poke_peer(struct sip_peer *peer, int force) { |