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From: Keith Mannthey <kmannth@gmail.com>
To: "Davda, Bhavesh P (Bhavesh)" <bhavesh@avaya.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Debugging kernel semaphore contention and priority inversion
Date: Wed, 17 Aug 2005 16:33:13 -0700	[thread overview]
Message-ID: <a762e240508171633ea4d903@mail.gmail.com> (raw)
In-Reply-To: <21FFE0795C0F654FAD783094A9AE1DFC0830FC77@cof110avexu4.global.avaya.com>

On 8/17/05, Davda, Bhavesh P (Bhavesh) <bhavesh@avaya.com> wrote:
> Is there a way to know which task has a particular (struct semaphore *)
> down()ed, leading to another task's down() blocking on it?

I would add a field to struct semaphore that tracks the current process.
In your various up and downs have that field tracks the "current" process. 

Do you know what semaphore it is?

This way you dump the semaphore you can see what task it is holding
it.  Have the module dump the semaphore and you can id the task
 
> It would be helpful to get a kernel stacktrace for the culprit too.

Have you tried sysrq t?  See the Documentation/sysrq.txt file.
 
How stuck is the system? 

Keith

  reply	other threads:[~2005-08-17 23:33 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-08-17 22:52 Debugging kernel semaphore contention and priority inversion Davda, Bhavesh P (Bhavesh)
2005-08-17 23:33 ` Keith Mannthey [this message]
  -- strict thread matches above, loose matches on Subject: below --
2005-08-18  3:43 Davda, Bhavesh P (Bhavesh)
2005-08-18 17:39 ` Keith Mannthey
2005-08-18 14:50 Davda, Bhavesh P (Bhavesh)
2005-08-18 15:13 ` Hal Wigoda
2005-08-18 15:15 ` Steven Rostedt
2005-08-18 17:50 Davda, Bhavesh P (Bhavesh)
     [not found] <21FFE0795C0F654FAD783094A9AE1DFC0830FE03@cof110avexu4.glob al.avaya.com>
2005-08-19  5:16 ` Mike Galbraith

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