sysmocom
/
asterisk
11
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

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
This commit is contained in:
Matthew Jordan 2013-03-26 02:30:10 +00:00
parent ec7de8ed97
commit 58ee2b7d11
1 changed files with 7 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
channels/chan_sip.c
View File

@ -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)
{