[asterisk-bugs] [Asterisk 0012101]: SIP channel hung due to CANCEL ReliableXmit (ReTX)
Asterisk Bug Tracker
noreply at bugs.digium.com
Mon Sep 15 16:50:45 CDT 2008
A NOTE has been added to this issue.
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http://bugs.digium.com/view.php?id=12101
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Reported By: MVF
Assigned To: murf
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Project: Asterisk
Issue ID: 12101
Category: Channels/chan_sip/General
Reproducibility: always
Severity: minor
Priority: normal
Status: assigned
Asterisk Version: 1.4.18
SVN Branch (only for SVN checkouts, not tarball releases): N/A
SVN Revision (number only!):
Disclaimer on File?: N/A
Request Review:
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Date Submitted: 2008-02-28 13:23 CST
Last Modified: 2008-09-15 16:50 CDT
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Summary: SIP channel hung due to CANCEL ReliableXmit (ReTX)
Description:
I've detected a problem that make asterisk keep sip channels up forever
even when the call has been disconnected, the problem keep UDP ports and
memory taken making asterisk to drop new calls when the sip channels hung
increase.
Reviewing the "sip show history" of one of these hung channels I see that
the call is cancel by calling party while is on ringing state, after that
asterisk send CANCEL to the peer but it didn't get an answer (maybe because
of network problems). After I get some bad responses from peer, maybe also
due to network problems that asterisk reply with an ACK but the history
shows a new ReliableXmit timeout message every 30 seconds.
(originating peer)
* SIP Call
1. TxReqRel INVITE / 102 INVITE - -UNKNOWN-
2. Rx SIP/2.0 / 102 INVITE / 100 Trying
3. Rx SIP/2.0 / 102 INVITE / 100 Trying
4. Rx SIP/2.0 / 102 INVITE / 180 Ringing
5. Rx SIP/2.0 / 102 INVITE / 180 Ringing
6. Cancel Cause Normal Clearing
7. SchedDestroy 32000 ms
8. TxReqRel CANCEL / 102 CANCEL - -UNKNOWN-
9. SchedDestroy 32000 ms
10. ReTx 1000 CANCEL sip:17898702397 at 20.20.20.25 SIP/2.0
11. ReTx 2000 CANCEL sip:17898702397 at 20.20.20.25 SIP/2.0
12. Rx SIP/2.0 / 102 CANCEL / 100 Trying
13. ReliableXmit timeout
14. Rx SIP/2.0 / 102 INVITE / 180 Ringing
15. Rx SIP/2.0 / 102 INVITE / 486 Busy Here
16. TxReq ACK / 102 ACK - -UNKNOWN-
17. ReliableXmit timeout
18. ReliableXmit timeout
19. ReliableXmit timeout
20. ReliableXmit timeout
21. ReliableXmit timeout
22. ReliableXmit timeout
23. ReliableXmit timeout
24. ReliableXmit timeout
25. ReliableXmit timeout
26. ReliableXmit timeout
27. ReliableXmit timeout
28. ReliableXmit timeout
29. ReliableXmit timeout
30. ReliableXmit timeout
31. ReliableXmit timeout
32. ReliableXmit timeout
33. ReliableXmit timeout
34. ReliableXmit timeout
35. ReliableXmit timeout
36. ReliableXmit timeout
37. ReliableXmit timeout
38. ReliableXmit timeout
39. ReliableXmit timeout
40. ReliableXmit timeout
41. ReliableXmit timeout
42. ReliableXmit timeout
43. ReliableXmit timeout
44. ReliableXmit timeout
45. ReliableXmit timeout
46. ReliableXmit timeout
47. ReliableXmit timeout
48. ReliableXmit timeout
49. ReliableXmit timeout
50. ReliableXmit timeout
I got a capture for the sip transaction messages that generate these hung
sip channels, please take a look at it in the attached file including two
captures (20080227_sip_channel_hung_at_cancel_ReTX.txt), note that there is
no sip messages sent after the last ACK, the "ReliableXmit timeout"
messages appear in the history of the call filling the 50 slot buffer and
even deleting the old history messages. The "sip show channels" command
shows the channel hung forever.
20.20.20.25 1789870239 185d051b629 00102/00000 0x0 (nothing) No
(d) Tx: ACK
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Relationships ID Summary
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related to 0013235 Memory leak in Asterisk 1.4 and Trunk
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----------------------------------------------------------------------
(0092537) murf (administrator) - 2008-09-15 16:50
http://bugs.digium.com/view.php?id=12101#c92537
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Aha!
We were able to determine the problem I recorded in the last note. It's
not
a SIP driver problem at all. What's happening, is the dialplan is hanging
in a FUNC_ODBC call, and the app call never returns. So, the channel goes
into limbo, and eventually, the other end will send a CANCEL, to which the
driver will respond appropriately, but the channel will not be destroyed.
The pbx_start thread is still running, and thousands of these build up,
hang onto memory, file handles, etc.
We are theorizing why the func_odbc call is hanging, but it's a
connection
to sql server, and our guess is that the sql server is dropping the
connection. Tilghman supplied us a patch; it's not involving this issue,
so I'll make no more mention of it than this: if you see lots of hung
channels, check to see if you also have hung threads. If you have both,
it's probably not bug 12101, but this other problem.
Issue History
Date Modified Username Field Change
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2008-09-15 16:50 murf Note Added: 0092537
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