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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Ingo Molnar <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>,
	Andi Kleen <ak@suse.de>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: preempt bug in set_pmd_pfn?
Date: Tue, 04 Mar 2008 13:13:43 -0800	[thread overview]
Message-ID: <47CDBB87.8090906@goop.org> (raw)

I think set_pmd_pfn, which is only called by __set_fixmap, might have a 
preempt bug in it.

It can be executed with preemption enabled, but what if it gets preempted

	set_pmd(pmd, pfn_pmd(pfn, flags));
	/*
	 * It's enough to flush this one mapping.
	 * (PGE mappings get flushed as well)
	 */
>here<
	__flush_tlb_one(vaddr);
}

?


Won't this leave a stale tlb on the old processor?

I noticed this because the Xen tlb flushing code effectively has a 
smp_processor_id(), which provokes a warning when preemption is 
enabled.  It seems to me that it never makes sense to be doing a tlb 
flush unless you know which processor you're actually running on...

    J

             reply	other threads:[~2008-03-04 21:19 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-04 21:13 Jeremy Fitzhardinge [this message]
2008-03-04 21:28 ` Ingo Molnar
2008-03-04 21:27   ` Jeremy Fitzhardinge
2008-03-05  6:48     ` Ingo Molnar
2008-03-05 14:29       ` Hugh Dickins
2008-03-05 16:48         ` Jeremy Fitzhardinge
2008-03-05 17:38           ` Hugh Dickins
2008-03-05 19:18             ` Jeremy Fitzhardinge
2008-03-05 20:40               ` Hugh Dickins
2008-03-06 12:52               ` Ingo Molnar
2008-03-06 18:19                 ` Jeremy Fitzhardinge
2008-03-05 16:45       ` Jeremy Fitzhardinge
2008-03-05  0:06 ` Andi Kleen
2008-03-05  0:07   ` Jeremy Fitzhardinge
2008-03-05  0:16     ` Andi Kleen
2008-03-05  0:19       ` Jeremy Fitzhardinge
2008-03-05  1:28         ` Andi Kleen

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