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Date: Thu, 13 Feb 2014 12:53:45 -0800
From: Alfred Perlstein <bright@mu.org>
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To: Vijay Singh <vijju.singh@gmail.com>, hackers@freebsd.org
Subject: Re: Debugging rw lock
References: <CALCNsJS6vFJU18F3VRR-T2RdtGNxd3fycUCkQ63BmGp29DAUMw@mail.gmail.com>
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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
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