From: Jay Foad <jay.foad@gmail.com>
To: Aurelien Jarno <aurelien@aurel32.net>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] gcc 4.4 miscompiling cpu_exec() ?
Date: Tue, 23 Feb 2010 17:57:23 +0000 [thread overview]
Message-ID: <ee2e06e91002230957y27212a5avdf3d0a834d9f63a@mail.gmail.com> (raw)
In-Reply-To: <4B840A59.3060407@aurel32.net>
On 23 February 2010 17:03, Aurelien Jarno <aurelien@aurel32.net> wrote:
> Jay Foad a écrit :
>> I'm building QEMU mipsel-linux-user with Ubuntu's GCC 4.4 on an x86
>> host. Whenever I try to run a trivial MIPS executable, QEMU segfaults
>> in cpu_loop() shortly after the call to cpu_mips_exec().
>>
>> The problem seems to be that cpu_exec() doesn't preserve ebp. It tries to:
>>
>> saved_env_reg = (host_reg_t) env;
>>
>> where env is a global variable decorated with asm("ebp"). This saves
>> ebp to the stack, but later on, in some function inlined into
>> cpu_exec(), the value on the stack gets overwritten with something
>> else.
>>
>> Has anyone else seen this?
>>
>
> Yes, but only in qemu 0.12.0 to 0.12.1. The issue should be fixed in the
> stable branch and in head.
I'm seeing it today, with sources from git:
git://git.qemu.org/qemu.git
commit 724c689357211cb929c9b957e1556f211d2b56db
Thanks,
Jay.
next prev parent reply other threads:[~2010-02-23 17:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-23 14:50 [Qemu-devel] gcc 4.4 miscompiling cpu_exec() ? Jay Foad
[not found] ` <4B840A59.3060407@aurel32.net>
2010-02-23 17:57 ` Jay Foad [this message]
2010-02-23 17:58 ` [Qemu-devel] " Paolo Bonzini
2010-02-23 18:17 ` Jay Foad
2010-02-23 18:18 ` Paolo Bonzini
2010-02-23 18:21 ` [Qemu-devel] [PATCH] declare saved_env_reg as volatile Paolo Bonzini
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