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Re: [Xen-devel] BUG: x86-64 VT crash backtrace

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] BUG: x86-64 VT crash backtrace
From: Rik van Riel <riel@xxxxxxxxxx>
Date: Tue, 25 Jul 2006 13:09:05 -0400
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx, jun.nakajima@xxxxxxxxx
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Keir Fraser wrote:

On 25 Jul 2006, at 17:02, Rik van Riel wrote:

Hi Jun,

here is the x86-64 VT crash backtrace, as promised. I can trigger it within minutes by simply starting up a 64 bit VT domain on a 64 bit system.

The hideously long (but apparently valid) call sequence has overflowed the 4kB Xen stack. Given that stacks are only per-cpu on x86 Xen, I should probably just make them bigger (perhaps 8kB on debug builds, 16kB on non-debug builds). 64-bit non-debug builds already have (almost) 8kB stacks, so shouldn't see this crash.

These crashes are on a 64 bit system.

So yes, even with 8kB stacks it crashes.

"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it." - Brian W. Kernighan

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