Re: v2.6.27-rc7: x86: #GP on panic?

From: H. Peter Anvin
Date: Thu Sep 25 2008 - 16:50:39 EST


Vegard Nossum wrote:

But I don't see how the divide error could occur here:

ffffffff8103918b: fb sti
ffffffff8103918c: 49 c7 c4 80 c0 6e 81 mov $0xffffffff816ec080,%r12
ffffffff81039193: f6 c3 01 test $0x1,%bl
ffffffff81039196: 74 27 je ffffffff810391bf <__do_so
ffffffff81039198: 4c 89 e7 mov %r12,%rdi
ffffffff8103919b: 41 ff 14 24 callq *(%r12)

Seems like an external interrupt happened and was delivered after the sti?

Hm. I guess it smells like a qemu bug since it's rather easily
reproducible here and sounds strange that nobody else saw it. Is qemu
0.9.1.


Yes, but there shouldn't be any external interrupts that could turn into a divide error. It really smells like a Qemu problem -- possibly even a Qemu miscompile -- to me.

Does it reproduce in KVM?

-hpa
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