From: Aurelien Degremont <aurelien.degremont@cea.fr>
To: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Jacques-Charles Lafoucriere <jc.lafoucriere@cea.fr>,
Bruno Faccini <bruno.faccini@bull.net>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Fix deadlock in RPC scheduling code.
Date: Mon, 13 Mar 2006 11:07:52 +0100 [thread overview]
Message-ID: <200603131007.LAA10812@styx.bruyeres.cea.fr> (raw)
In-Reply-To: <1142004255.8041.26.camel@lade.trondhjem.org>
Trond Myklebust wrote:
> Yes. The RPC_TASK_QUEUED bit can only be cleared when both the
> RPC_TASK_WAKEUP bit _and_ the queue spinlock are held.
> If you are holding either one of those two, then it is safe to test for
> RPC_IS_QUEUED(). If the latter is true, then it is also safe to
> dereference the value of task->u.tk_wait.rpc_waitq.
Hmmm... With those constraints, it seems difficult to be able to modify
the current rpc_wake_up_task() function...
But, are you sure the patch you provided is sufficient to remove the
potential deadlock we faced ? I do not see how, could you explain ?
--
Aurelien Degremont
next prev parent reply other threads:[~2006-03-13 10:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-09 10:35 Aurelien Degremont
2006-03-09 14:40 ` Trond Myklebust
2006-03-10 15:10 ` Aurelien Degremont
2006-03-10 15:24 ` Trond Myklebust
2006-03-13 10:07 ` Aurelien Degremont [this message]
2006-03-13 14:28 ` Trond Myklebust
2006-03-13 15:16 ` Aurelien Degremont
2006-03-13 16:08 ` Trond Myklebust
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