Re: [Libevent-users] [2.0.19-stable] Infinite loop

[sahil aggarwal <sahil.agg15@xxxxxxxxx>]

Azat,

Could this patch

https://github.com/libevent/libevent/commit/bc79cc5c80ee374dec0e968bc6fdf301d479e133

be related ?

On 15 September 2016 at 23:28, sahil aggarwal <sahil.agg15@xxxxxxxxx> wrote:
> Azat,
>
> Could this patch
>
>
> On 14 September 2016 at 18:48, sahil aggarwal <sahil.agg15@xxxxxxxxx> wrote:
>> Azat,
>>
>> Yes this happens every time server close the connection. To reproduce i :
>> * start my client (multiple threads but event_base being exclusive to
>> 1 thread handling the events)
>> * start server
>> * generate some requests from client which succeed
>> * stop server
>> * generate some requests where now it loops forever.
>>
>> I can write reproducer and try it with latest libevent too. In the
>> mean time i have live GDB attached, if you need any info let me know.
>>
>> Thanks
>>
>> On 14 September 2016 at 16:37, Azat Khuzhin <a3at.mail@xxxxxxxxx> wrote:
>>> On Wed, Sep 14, 2016 at 04:33:41PM +0530, sahil aggarwal wrote:
>>>> Hi,
>>>>
>>>> Getting stuck in infinite loop after retry on evhttp_connection. After
>>>> attaching GDB this is what i found:
>>>>
>>>> ----------
>>>>
>>>> #0  0x00007f9a8f5efdb9 in event_queue_remove (base=base@entry=0x24bf830,
>>>> ev=ev@entry=0x7f9a84006da0, queue=queue@entry=8)
>>>>     at event.c:2495
>>>> #1  0x00007f9a8f5f4040 in event_del_internal (ev=0x7f9a84006da0) at
>>>> event.c:2234
>>>> #2  timeout_process (base=0x24bf830) at event.c:2481
>>>> #3  event_base_loop (base=base@entry=0x24bf830, flags=flags@entry=0) at
>>>> event.c:1614
>>>>
>>>>
>>>> ---------
>>>>
>>>> #0  event_active_nolock (ev=<optimized out>, res=<optimized out>,
>>>> ncalls=<optimized out>) at event.c:2315
>>>> #1  0x00007f9a8f5f3f76 in timeout_process (base=0x24bf830) at event.c:2485
>>>> #2  event_base_loop (base=base@entry=0x24bf830, flags=flags@entry=0) at
>>>> event.c:1614
>>>>
>>>>
>>>> So the event is getting removed and queued in active queue. And event given
>>>> by
>>>>
>>>> ev = min_heap_top(&base->timeheap)
>>>>
>>>> doesn't have EV_TIMEOUT flag set due which it won't remove from the
>>>> min_heap and it always get the same event on the top hence the infinite
>>>> loop.
>>>>
>>>> * event_base not being shared across multiple threads.
>>>>
>>>> * How 1 have event in min_heap without EV_TIMEOUT  flag set and
>>>> e->ev_timeout_pos.min_heap_idx = -1  as on adding we always set the flag ?
>>>
>>> Hi,
>>>
>>> Does it triggers every time? If so can you please try libevent from
>>> sources (https://github.com/libevent/libevent)? And does you program
>>> single-threaded or multi?
>>>
>>> Also if you have a reproducer (~100 lines) it will be useful to see it.
>>>
>>> Thanks,
>>> Azat.
>>> ***********************************************************************
>>> To unsubscribe, send an e-mail to majordomo@xxxxxxxxxxxxx with
>>> unsubscribe libevent-users    in the body.
***********************************************************************
To unsubscribe, send an e-mail to majordomo@xxxxxxxxxxxxx with
unsubscribe libevent-users    in the body.