From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Eugene Surovegin <ebs@ebshome.net>
Cc: linuxppc-dev@ozlabs.org, Kumar Gala <kumar.gala@freescale.com>
Subject: Re: Unsafe pte_update() in do_page_fault() (4xx and Book-E)
Date: Fri, 03 Mar 2006 14:43:02 +1100 [thread overview]
Message-ID: <1141357383.3888.19.camel@localhost.localdomain> (raw)
In-Reply-To: <20060302202634.GA14387@gate.ebshome.net>
> If this happens, pte_update() sets _PAGE_HWEXEC bit in just cleared
> PTE. Sometime later, another page fault happens for this page, but
> because of that set bit, pte_none() test in handle_pte_fault() fails,
> and we continue along the wrong path, thinking that this PTE was
> swapped out to the swap file, and this triggers swap_dup error I
> mentioned at the beginning.
Can we preempt at that point ? As tehre is no SMP 4xx that I know of
preempt would be the only cause for such a race ...
Ben.
next prev parent reply other threads:[~2006-03-03 3:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-02 20:26 Unsafe pte_update() in do_page_fault() (4xx and Book-E) Eugene Surovegin
2006-03-03 3:43 ` Benjamin Herrenschmidt [this message]
2006-03-03 3:55 ` Eugene Surovegin
2006-03-28 7:55 ` [PATCH] lock PTE before updating it in 440/BookE page fault handler Eugene Surovegin
2006-03-28 11:10 ` Paul Mackerras
2006-03-28 18:13 ` Eugene Surovegin
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