From: Andi Kleen <andi@firstfloor.org>
To: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Andi Kleen <andi@firstfloor.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Fix x86_64 TIF_SYSCALL_TRACE race in entry.S
Date: Sun, 28 Oct 2007 22:21:50 +0100 [thread overview]
Message-ID: <20071028212150.GA20321@one.firstfloor.org> (raw)
In-Reply-To: <20071028211527.GA9129@Krystal>
> Setting the thread flag being an atomic operation, I would expect
> setting/clearing it asynchronously from another thread to be a valid
It could be a very short stop. Also do you start kernel tracing that often?
> Here is a modified version where I add my test only in the path where we
> know that we have work to do, therefore removing the supplementary test
> from the performance critical path. Would it be more acceptable ?
It's better, but stopping would be even better. I wouldn't
be surprised if there are other problems with async thread flags changing.
Also I object to you calling this a bug. It's a new feature.
-Andi
next prev parent reply other threads:[~2007-10-28 21:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-26 19:37 Adding TIF_TRACE_KERNEL to x86_64 Mathieu Desnoyers
2007-10-27 18:08 ` [PATCH] Fix x86_64 TIF_SYSCALL_TRACE race in entry.S Mathieu Desnoyers
2007-10-27 19:04 ` Andi Kleen
2007-10-28 21:15 ` Mathieu Desnoyers
2007-10-28 21:21 ` Andi Kleen [this message]
2007-10-28 22:31 ` Mathieu Desnoyers
2007-10-27 19:00 ` Adding TIF_TRACE_KERNEL to x86_64 Andi Kleen
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