[sr-dev] TM possible deadlock
Daniel-Constantin Mierla
miconda at gmail.com
Thu Apr 10 09:01:37 CEST 2014
Hello Jason,
I pushed a patch trying to fix this case, it is only on git master
branch. Can you test it? If all goes fine, we can consider backporting it.
Cheers,
Daniel
On 09/04/14 23:26, Jason Penton wrote:
> Hey Daniel,
>
> nothing extraordinary...
>
> # -- TM params --
> modparam("tm", "fr_timer", 20000);
> modparam("tm", "fr_inv_timer", 10000)
>
>
> Cheers
> Jason
>
>
> On Wed, Apr 9, 2014 at 10:32 PM, Jason Penton <jason.penton at gmail.com
> <mailto:jason.penton at gmail.com>> wrote:
>
> Hey Daniel,
>
> Yes I did a test with a very basic config file and I am not able
> to re-create. However, with my *complex* cfg file I can re-create
> every time. Tomorrow I will compare what is different and report
> back... hopefully with fix ;)
>
> here is bt of timer process deadlocking itself:
>
> #0 syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:39
> #1 0x00007f5009f22004 in futex_get (lock=0x7f4fc55030d8) at
> ../../mem/../futexlock.h:123
> #2 0x00007f5009f223e1 in _lock (s=0x7f4fc55030d8,
> file=0x7f5009f90fd1 "t_cancel.c", function=0x7f5009f91980
> "cancel_branch", line=250) at lock.h:99
> #3 0x00007f5009f23271 in cancel_branch (t=0x7f4fc5501b40,
> branch=0, reason=0x7fff646d03a8, flags=3) at t_cancel.c:250
> #4 0x00007f5009f22c02 in cancel_uacs (t=0x7f4fc5501b40,
> cancel_data=0x7fff646d03a0, flags=1) at t_cancel.c:123
> #5 0x00007f5009f718c4 in _reply_light (trans=0x7f4fc5501b40,
> buf=0x7f500a24dc68 "SIP/2.0 500 Server error on LIR select
> next S-CSCF\r\nVia: SIP/2.0/UDP
> 10.0.1.167:6060;branch=z9hG4bKb7.2ae09f29ffbd0034cd6d58483053603b.1\r\nVia:
> SIP/2.0/UDP 10.0.1.166:4060;branch=z9hG4bKb7.3faa03ddea80"...,
> len=778, code=500, to_tag=0x7f500a1c7ae0
> "c82b15d7f12ef185f95fe4945457d449-8bab", to_tag_len=37, lock=0,
> bm=0x7fff646d0b60) at t_reply.c:660
> #6 0x00007f5009f7244c in _reply (trans=0x7f4fc5501b40,
> p_msg=0x7f500a1c6bc0, code=500, text=0x7f500a249a48 "Server error
> on LIR select next S-CSCF", lock=0) at t_reply.c:795
> #7 0x00007f5009f76436 in t_reply_unsafe (t=0x7f4fc5501b40,
> p_msg=0x7f500a1c6bc0, code=500, text=0x7f500a249a48 "Server error
> on LIR select next S-CSCF") at t_reply.c:1643
> #8 0x00007f5009f57621 in w_t_reply (msg=0x7f500a1c6bc0,
> p1=0x7f500a2497d8 "\340\332$\nP\177", p2=0x7f500a249870
> "h\321$\nP\177") at tm.c:1324
> #9 0x000000000041a700 in do_action (h=0x7fff646d1d30,
> a=0x7f500a24cee8, msg=0x7f500a1c6bc0) at action.c:1119
> #10 0x0000000000423831 in run_actions (h=0x7fff646d1d30,
> a=0x7f500a24cee8, msg=0x7f500a1c6bc0) at action.c:1607
> #11 0x000000000041a5a4 in do_action (h=0x7fff646d1d30,
> a=0x7f500a24d478, msg=0x7f500a1c6bc0) at action.c:1102
> #12 0x0000000000423831 in run_actions (h=0x7fff646d1d30,
> a=0x7f500a249148, msg=0x7f500a1c6bc0) at action.c:1607
> #13 0x000000000041a54e in do_action (h=0x7fff646d1d30,
> a=0x7f500a24c500, msg=0x7f500a1c6bc0) at action.c:1098
> #14 0x0000000000423831 in run_actions (h=0x7fff646d1d30,
> a=0x7f500a247a28, msg=0x7f500a1c6bc0) at action.c:1607
> #15 0x0000000000423fdf in run_top_route (a=0x7f500a247a28,
> msg=0x7f500a1c6bc0, c=0x0) at action.c:1693
> #16 0x00007f5009f73815 in run_failure_handlers (t=0x7f4fc5501b40,
> rpl=0xffffffffffffffff, code=408, extra_flags=96) at t_reply.c:1061
> #17 0x00007f5009f7527a in t_should_relay_response
> (Trans=0x7f4fc5501b40, new_code=408, branch=1,
> should_store=0x7fff646d201c, should_relay=0x7fff646d2018,
> cancel_data=0x7fff646d2070,
> reply=0xffffffffffffffff) at t_reply.c:1416
> #18 0x00007f5009f76ede in relay_reply (t=0x7f4fc5501b40,
> p_msg=0xffffffffffffffff, branch=1, msg_status=408,
> cancel_data=0x7fff646d2070, do_put_on_wait=0) at t_reply.c:1819
> #19 0x00007f5009f44c88 in fake_reply (t=0x7f4fc5501b40, branch=1,
> code=408) at timer.c:354
> #20 0x00007f5009f450e7 in final_response_handler
> (r_buf=0x7f4fc5501e60, t=0x7f4fc5501b40) at timer.c:526
> #21 0x00007f5009f4518d in retr_buf_handler (ticks=260027386,
> tl=0x7f4fc5501e80, p=0x3e8) at timer.c:584
> #22 0x0000000000544119 in timer_list_expire (t=260027386,
> h=0x7f4fc527cbe0, slow_l=0x7f4fc527cdf0, slow_mark=0) at timer.c:894
> #23 0x0000000000544418 in timer_handler () at timer.c:959
> #24 0x00000000005446b2 in timer_main () at timer.c:998
> #25 0x0000000000471ddf in main_loop () at main.c:1689
>
>
>
> On Wed, Apr 9, 2014 at 9:34 PM, Daniel-Constantin Mierla
> <miconda at gmail.com <mailto:miconda at gmail.com>> wrote:
>
> Hello,
>
> that should not be a very rare case and I would expect to be
> caught so far, anyhow ... this looks like easy to reproduce,
> have you tried it?
>
> You can have two kamailio, one relying the invite to the
> second, which will reply with 100, then wait for the timeout
> on the first instance. You can add some debug messages in the
> code to see if the lock is called twice.
>
> Cheers,
> Daniel
>
>
> On 09/04/14 17:51, Jason Penton wrote:
>> Hi All,
>>
>> I have been experiencing a deadlock when a timeout occurs on
>> a t_relayed() INVITE. Going through the code I have noticed a
>> possible chance of deadlock (without re-entrant enabled).
>> Here is my thinking:
>>
>> t_should_relay_response() is called with REPLY_LOCK when the
>> timer process fires on the fr_inv_timer (no response from the
>> INVITE that was relayed, other than 100 provisional) and a
>> 408 is generated. However, from within that function there
>> are calls to run_failure_handlers() which in turn *could* try
>> and lock the reply (viz. somebody having a t_reply() call in
>> the cfg file - in failure route block). This would result in
>> another lock on the same transaction's REPLY_LOCK....
>>
>> Has anybody else experienced something like this?
>>
>> this is on master btw.
>>
>> Cheers
>> Jason
>>
>>
>> _______________________________________________
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>> http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-dev
>
> --
> Daniel-Constantin Mierla -http://www.asipto.com
> http://twitter.com/#!/miconda <http://twitter.com/#%21/miconda> -http://www.linkedin.com/in/miconda
>
>
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>
>
--
Daniel-Constantin Mierla - http://www.asipto.com
http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
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