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From: Aurelien Jarno <aurelien@aurel32.net>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] TCG/GCC breakage
Date: Wed, 11 Mar 2009 09:32:22 +0100	[thread overview]
Message-ID: <20090311083222.GA21685@volta.aurel32.net> (raw)
In-Reply-To: <5d6222a80903102040reef9775s8aaf9975e7594133@mail.gmail.com>

On Wed, Mar 11, 2009 at 12:40:20AM -0300, Glauber Costa wrote:
> I'm seeing a strange behaviour here using qemu-system-x86_64
> (kvm not even compiled in) on an i386 host
> 
> I'm suspecting gcc is doing something nasty in here, but I'll open it
> up here to see if any
> of you have any suggestion.
> 
> I get segfaults very early in execution, and after some investigation,
> I figured out that
> ebp register is corrupted. I can't determine where the corruption starts.

Does QEMU segfault, or processes in the guest? How to reproduce that?
Which QEMU version are you using? I am able to run a Debian Etch x86_64 
guest without problem here.

> I then did rm x86-64-softmmu/op_helper.o; make CC=gcc34, so only this
> file get compiled
> by an older gcc, and it worked again.

Which versions of gcc did you tried? I am using gcc 4.3 here.

> So it seems to me gcc may be generating gibberish somewhere in
> helpers, but since
> this code is a bit fragile, it might well be some mistake on our part.
> 
> Ideas on how to attack it ?
> 

You may want to use the -d option to find the offending helper function.

-- 
Aurelien Jarno	                        GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net

  reply	other threads:[~2009-03-11  8:32 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-03-11  3:40 [Qemu-devel] TCG/GCC breakage Glauber Costa
2009-03-11  8:32 ` Aurelien Jarno [this message]
2009-03-11 10:34 ` Paul Bolle
2009-03-16  8:26 ` Aurelien Jarno

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