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Re: [MIPS] Fix aliasing bug in copy_user_highpage, take 2.

To: linux-mips@linux-mips.org
Subject: Re: [MIPS] Fix aliasing bug in copy_user_highpage, take 2.
From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Date: Tue, 16 Oct 2007 02:31:25 +0900 (JST)
Cc: ralf@linux-mips.org
In-reply-to: <S20036863AbXJOPrf/20071015154735Z+80955@ftp.linux-mips.org>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <S20036863AbXJOPrf/20071015154735Z+80955@ftp.linux-mips.org>
Sender: linux-mips-bounce@linux-mips.org
On Mon, 15 Oct 2007 16:47:30 +0100, linux-mips@linux-mips.org wrote:
> Turns out 6a36458d9348265327d074bdd40bfb1c5b6fb2cb  wasn't quite right.
> When called for a page that isn't marked dirty it would artificially
> create an alias instead of doing the obvious thing and access the page
> via KSEG0.
> 
> The same issue also exists in copy_to_user_page and copy_from_user_page
> which was causing the machine to die under rare circumstances for example
> when running ps if the BUG_ON() assertion added by the earlier fix was
> getting triggered.

This commit added a SetPageDcacheDirty() call for both
copy_to_user_page() and copy_from_user_page().  The call in
copy_from_user_page() is really needed?

---
Atsushi Nemoto

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