Date: Thu, 13 Feb 2014 14:06:27 -0700 From: Ian Lepore <ian@FreeBSD.org> To: Vijay Singh <vijju.singh@gmail.com> Cc: hackers@FreeBSD.org Subject: Re: Debugging rw lock Message-ID: <1392325587.1145.96.camel@revolution.hippie.lan> In-Reply-To: <CALCNsJQzeqGh%2BZ0rW2jw9e%2BDfKdaRo9BpOQq7XrjfZ1EzNDFYQ@mail.gmail.com> References: <CALCNsJS6vFJU18F3VRR-T2RdtGNxd3fycUCkQ63BmGp29DAUMw@mail.gmail.com> <52FD30D9.6050604@mu.org> <CALCNsJQzeqGh%2BZ0rW2jw9e%2BDfKdaRo9BpOQq7XrjfZ1EzNDFYQ@mail.gmail.com>
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Does option DEADLKRES not work with rwlocks? (I've never used it, just
seen it in the NOTES).
-- Ian
On Thu, 2014-02-13 at 12:59 -0800, Vijay Singh wrote:
> 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@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
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> >
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