Debugging rw lock

[Vijay Singh]

You're talking about instrumenting the code, right? But which thread? I was
thinking of augmenting the rw lock to record the readers, but wanted to
check if something is possible without instrumentation.


On Thu, Feb 13, 2014 at 12:53 PM, Alfred Perlstein <bright at mu.org> wrote:

> Keep a stack of rwlocks owned in the struct thread.
>
> -Alfred
>
> On 2/13/14, 12:51 PM, Vijay Singh wrote:
>
>> I am running into an issue where an rw lock is read locked and never
>> unlocked, and causes a system to livelock. I was wondering if its possible
>> to figure out which thread owns the read lock?
>>
>> It's the tcp pcbinfo lock.
>>
>> (kgdb-amd64-7.4-08) show_rwlock rw
>>   name : tcp
>>   class: rw
>>   flags: {SLEEP, INITED, WITNESS, RECURSE, UPGRADABLE}
>>   state: RLOCK: 1 locks
>>   waiters: writers
>>
>> Any help is appreciated.
>>
>> -vijay
>> _______________________________________________
>> freebsd-hackers at freebsd.org mailing list
>> http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
>> To unsubscribe, send any mail to "freebsd-hackers-unsubscribe at freebsd.org
>> "
>>
>>
>