Date: Fri, 30 Apr 2004 19:19:01 -0700
From: Andrew Morton <akpm@osdl.org>
To: vatsa@in.ibm.com
Cc: rusty@rustcorp.com.au, mingo@elte.hu, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Fix deadlock in __create_workqueue
Message-Id: <20040430191901.510ae947.akpm@osdl.org>
In-Reply-To: <20040430113751.GA18296@in.ibm.com>
References: <20040430113751.GA18296@in.ibm.com>
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Srivatsa Vaddagiri <vatsa@in.ibm.com> wrote:
>
> Noticed a possible deadlock in __create_workqueue when CONFIG_HOTPLUG_CPU is
> set.  This can happen when create_workqueue_thread fails to create a worker
> thread. In that case, we call destroy_workqueue with cpu hotplug lock held.
> destroy_workqueue however also attempts to take the same lock.
> 
> Patch below address this deadlock as well as a kthread_stop race. 

Fixing a kthread_stop() race is a quite different thing from fixing a
create-workqueue() error-path deadlock and hence should be a separate
patch.

And the description of that separate patch should explain the race which
it is fixing!  Yes, the logic in worker_thread() is a bit dorky, but I
don't believe that there is a race in there.

I dropped that part of your patch.  Please resend, with justification, if
you disagree.

Thanks.
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