Re: undetected closed apps

[Vlad Yasevich <vyasevich@gmail.com>]

On 12/17/2013 08:49 AM, Jamal Hadi Salim wrote:
> On 12/16/13 10:19, Vlad Yasevich wrote:
>> On 12/14/2013 10:04 AM, Jamal Hadi Salim wrote:
> 
>> Hi Jamal
>>
>> The only thing I can think off that may be causing this is the
>> rcu-fication of the transport list in the associations.
>>
>> You might be able to test by reverting:
>>    771085d6bf3c52de29fc213e5bad07a82e57c23e
>>    8c98653f05534acd1cb07ea4929702a3659177d1
>>    45122ca26ced7fae41049326a3797a73f961db2e
> 
> 
> Thanks Vlad. I will try newer kernels and revert these changes
> incrementally and see if there's improvement.
> 
> BTW: What tools are useful to monitor sctp behavior?
> For this case I have been watching activity using
> /proc/net/sctp/assocs, strace and tcpdump.

That's about it.  You can also use stap.  It's on the project
todo list to provide some good stap scripts.

The other thing that is useful for debugging things like this is
the object counting in SCTP (CONFIG_SCTP_DBG_OBJCNT), but it's a
kernel config option so not sure how easily you'd be able to use
it.

> 
> cheers,
> jamal
> 
> PS: I currently have no choice on what kernels already deployed
> that need the software feature but can make recommendations
> for future upgrades. It would be good to narrow it down.

The initial commit 45122ca26ced7fae41049326a3797a73f961db2e was
added to 3.8.  In 3.9 we fixed a bug where the association closures
were being delayed too long and were preventing socket rebinding
(commit 8c98653f05534acd1cb07ea4929702a3659177d1).