From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Zachary Amsden <zach@vmware.com>
Cc: Virtualization Mailing List <virtualization@lists.osdl.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@osdl.org>,
Chris Wright <chrisw@sous-sol.org>,
Rusty Russell <rusty@rustcorp.com.au>, Andi Kleen <ak@suse.de>,
Andrew Morton <akpm@osdl.org>,
Ben Collins <ben.collins@ubuntu.com>
Subject: Re: [PATCH] Fix lazy mode vmalloc synchronization for paravirt
Date: Tue, 21 Aug 2007 23:28:28 -0700 [thread overview]
Message-ID: <46CBD78C.3020804@goop.org> (raw)
In-Reply-To: <46CB91BC.2010808@vmware.com>
Zachary Amsden wrote:
> Found this looping Ubuntu installs with VMI.
>
> If unlucky enough to hit a vmalloc sync fault during a lazy mode
> operation (from an IRQ handler for a module which was not yet
> populated in current page directory, or from inside copy_one_pte,
> which touches swap_map, and hit in an unused 4M region), the required
> PDE update would never get flushed, causing an infinite page fault loop.
Ah, good catch.
> This bug affects any paravirt-ops backend which uses lazy updates, I
> believe that makes it a bug in Xen, VMI and lguest. It only happens
> on LOWMEM kernels.
No, under Xen the kernel/hypervisor PMD is not shared between processes,
so this is still used when PAE is enabled.
J
next prev parent reply other threads:[~2007-08-22 6:28 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-22 1:30 [PATCH] Fix lazy mode vmalloc synchronization for paravirt Zachary Amsden
2007-08-22 1:30 ` Zachary Amsden
2007-08-22 6:28 ` Jeremy Fitzhardinge [this message]
2007-08-22 6:52 ` Zachary Amsden
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