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Re: [Xen-devel] [PATCH][PVFB][LINUX] Fix possible sleep while holding sp

To: Markus Armbruster <armbru@xxxxxxxxxx>, Keir Fraser <keir@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH][PVFB][LINUX] Fix possible sleep while holding spinlock
From: Keir Fraser <keir@xxxxxxxxxxxxx>
Date: Fri, 15 Dec 2006 18:06:13 +0000
Cc: Atsushi SAKAI <sakaia@xxxxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx, xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
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Thread-topic: [Xen-devel] [PATCH][PVFB][LINUX] Fix possible sleep while holding spinlock
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On 15/12/06 16:38, "Markus Armbruster" <armbru@xxxxxxxxxx> wrote:

> This patch fixes the locking, but leaves open a race between
> xenfb_update_screen() and do_no_page().  See the source code for a
> detailed explanation of how it works, and where it fails.

That's a bit of a shame. Is there any way we could use do_file_page() and
have a populate hook (which gets to install the PTE itself)? Or are there
lots of assumptions about VMAs that would take this path, assert

 -- Keir

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