From: George Dunlap <george.dunlap@eu.citrix.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Xen-devel <xen-devel@lists.xensource.com>,
Keir Fraser <Keir.Fraser@eu.citrix.com>
Subject: Re: So I tried to use xentrace...
Date: Fri, 7 May 2010 16:16:34 -0500 [thread overview]
Message-ID: <4BE48332.6040209@eu.citrix.com> (raw)
In-Reply-To: <4BE47F26.50904@goop.org>
Jeremy Fitzhardinge wrote:
>>> (XEN) ----[ Xen-4.1-unstable x86_64 debug=y Not tainted ]----
>>> (XEN) CPU: 1
>>> (XEN) RIP: e008:[<ffff82c4801215b3>] check_lock+0x1b/0x45
>>>
>>>
>
> This suggests the problem is with misusing a lock in the wrong interrupt
> context, rather than anything to do with sizes.
>
Except that, it works for me if I use -S 32, and doesn't if I use -S 512
(on my 2-core box, equivalent # of pages to -S 256 on your 4-core box).
:-) Try it, I suspect it will work.
Also:
* It's a page fault with a null pointer, not a bugcheck. In a non-debug
build, it will crash in spin_lock instead of check_lock.
* The fault is in the MMU update hypercall; I believe done when xentrace
tries to map garbage pages or invalid MFNs.
* This is the exact bug we were getting in product, and the
bounds-checking fixed it.
Hmm... the bounds checking should be working. The maximum index is
meant to be 2048 (2 pages = 8k, / sizeof(uint32_t) = 2048), and the
maximum index for you is 1088, well within the t_info size. Hmm...
-George
next prev parent reply other threads:[~2010-05-07 21:16 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-30 21:34 So I tried to use xentrace Jeremy Fitzhardinge
2010-04-30 21:43 ` Keir Fraser
2010-05-03 20:36 ` George Dunlap
2010-05-07 20:48 ` George Dunlap
2010-05-07 20:59 ` Jeremy Fitzhardinge
2010-05-07 21:16 ` George Dunlap [this message]
2010-05-08 5:03 ` Jeremy Fitzhardinge
2010-05-11 18:56 ` George Dunlap
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