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Re: [Xen-devel] Re: [PATCH] Fix debug exception stack to enable gdb on x

To: Andi Kleen <ak@xxxxxxx>
Subject: Re: [Xen-devel] Re: [PATCH] Fix debug exception stack to enable gdb on xeno64
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Tue, 12 Jul 2005 18:21:59 +0100
Cc: "Li, Xin B" <xin.b.li@xxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
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On 12 Jul 2005, at 18:10, Andi Kleen wrote:

Doesn't look correct to me. When you get an NMI or DB directly after
a SYSCALL to Xen it'll execute on a random stack and likely break
if the guest runs with a broken stack at that time.

Also I can really recommend having IST stacks for double fault and stack
fault, otherwise everytime you break the stack you get a triple fault
which are nasty to debug. You guys with target probes might not
care that much, but others do.

The patch is for guest Linux. Xen itself does use IST stacks, just like native Linux.

 -- Keir

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