From: Carsten Otte <cotte@de.ibm.com>
To: Nick Piggin <npiggin@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
borntrae@linux.vnet.ibm.com, Jared Hulbert <jaredeh@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Hugh Dickins <hugh@veritas.com>
Subject: Re: [patch] mm: xip fix fault vs sparse page invalidate race
Date: Mon, 18 Aug 2008 12:50:40 +0200 [thread overview]
Message-ID: <48A95400.5050003@de.ibm.com> (raw)
In-Reply-To: <20080818054409.GB3011@wotan.suse.de>
Nick Piggin wrote:
> XIP has a race between sparse pages being inserted into page tables, and
> sparse pages being zapped when its time to put a non-sparse page in.
>
> What can happen is that a process can be left with a dangling sparse page
> in a MAP_SHARED mapping, while the rest of the world sees the non-sparse
> version. Ie. data corruption.
>
> Guard these operations with a seqlock, making fault-in-sparse-pages
> the slowpath, and try-to-unmap-sparse-pages the fastpath.
>
> Signed-off-by: Nick Piggin <npiggin@suse.de>
Ouch.
Acked-by: Carsten Otte <cotte@de.ibm.com>
WARNING: multiple messages have this Message-ID (diff)
From: Carsten Otte <cotte@de.ibm.com>
To: Nick Piggin <npiggin@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
borntrae@linux.vnet.ibm.com, Jared Hulbert <jaredeh@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Hugh Dickins <hugh@veritas.com>
Subject: Re: [patch] mm: xip fix fault vs sparse page invalidate race
Date: Mon, 18 Aug 2008 12:50:40 +0200 [thread overview]
Message-ID: <48A95400.5050003@de.ibm.com> (raw)
In-Reply-To: <20080818054409.GB3011@wotan.suse.de>
Nick Piggin wrote:
> XIP has a race between sparse pages being inserted into page tables, and
> sparse pages being zapped when its time to put a non-sparse page in.
>
> What can happen is that a process can be left with a dangling sparse page
> in a MAP_SHARED mapping, while the rest of the world sees the non-sparse
> version. Ie. data corruption.
>
> Guard these operations with a seqlock, making fault-in-sparse-pages
> the slowpath, and try-to-unmap-sparse-pages the fastpath.
>
> Signed-off-by: Nick Piggin <npiggin@suse.de>
Ouch.
Acked-by: Carsten Otte <cotte@de.ibm.com>
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next prev parent reply other threads:[~2008-08-18 10:50 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-18 5:38 [patch] mm: dirty page tracking race fix Nick Piggin
2008-08-18 5:38 ` Nick Piggin
2008-08-18 5:44 ` [patch] mm: xip fix fault vs sparse page invalidate race Nick Piggin
2008-08-18 5:44 ` Nick Piggin
2008-08-18 6:03 ` [patch] mm: xip/ext2 fix block allocation race Nick Piggin
2008-08-18 6:03 ` Nick Piggin
2008-08-18 10:51 ` Carsten Otte
2008-08-18 10:51 ` Carsten Otte
2008-08-18 10:50 ` Carsten Otte [this message]
2008-08-18 10:50 ` [patch] mm: xip fix fault vs sparse page invalidate race Carsten Otte
2008-08-18 7:49 ` [patch] mm: dirty page tracking race fix Peter Zijlstra
2008-08-18 7:49 ` Peter Zijlstra
2008-08-18 8:03 ` Nick Piggin
2008-08-18 8:03 ` Nick Piggin
2008-08-18 8:07 ` Peter Zijlstra
2008-08-18 8:07 ` Peter Zijlstra
2008-08-18 8:12 ` Nick Piggin
2008-08-18 8:12 ` Nick Piggin
2008-08-19 9:11 ` Andrew Morton
2008-08-19 9:11 ` Andrew Morton
2008-08-19 10:19 ` Nick Piggin
2008-08-19 10:19 ` Nick Piggin
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