[sr-dev] TM possible deadlock

Jason Penton jason.penton at gmail.com
Fri Apr 11 14:45:32 CEST 2014 

yes okay - got it. I will test and analyse.

Thanks Daniel!


On Thu, Apr 10, 2014 at 4:35 PM, Daniel-Constantin Mierla <miconda at gmail.com
> wrote:

>  Hello,
>
> iirc, there are several functions that script writer can use, like
> t_reply_callid() from tmx. The idea is to analyze a bit in order to detect
> if a forced reply may end up in canceling some pending branches -- the
> reply on the branch doesnt matter anymore and should not be considered
> anymore for relaying upstream, because the script writer already decided
> what to send out.
>
> Cheers,
> Daniel
>
>
>
> On 10/04/14 13:24, Jason Penton wrote:
>
> Hey Daniel,
>
>  which reply functions are you referring to? API functions?
>
>  Cheers
> Jason
>
>
>  On Thu, Apr 10, 2014 at 12:53 PM, Daniel-Constantin Mierla <
> miconda at gmail.com> wrote:
>
>>  OK. I will leave it a bit in master to see if there are any new reports,
>> then I will backport. I will also have to review the tm reply functions
>> that can be used from config to align them to the new check.
>>
>> Cheers,
>> Daniel
>>
>>
>> On 10/04/14 09:06, Jason Penton wrote:
>>
>> 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
>>>
>>>
>>
>> --
>> Daniel-Constantin Mierla - http://www.asipto.comhttp://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
>>
>>
>
> --
> Daniel-Constantin Mierla - http://www.asipto.comhttp://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
>
>
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