[sr-dev] TM possible deadlock

Jason Penton jason.penton at gmail.com
Thu Apr 10 09:06:05 CEST 2014 

oh excellent, I will look at it right away - was just getting ready to jump
in myself ;)

Cheers
Jason


On Thu, Apr 10, 2014 at 9:01 AM, Daniel-Constantin Mierla <miconda at gmail.com
> wrote:

>  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>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> 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
>>>
>>>
>>>  _______________________________________________
>>> sr-dev mailing listsr-dev at lists.sip-router.orghttp://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-dev
>>>
>>>
>>> --
>>> Daniel-Constantin Mierla - http://www.asipto.comhttp://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
>>>
>>>
>>> _______________________________________________
>>> sr-dev mailing list
>>> sr-dev at lists.sip-router.org
>>> http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-dev
>>>
>>>
>>
>
> --
> Daniel-Constantin Mierla - http://www.asipto.comhttp://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
>
>
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