Re: [stable] [tip:x86/urgent] x86: Add memory modify constraints to xchg() and cmpxchg()

H. Peter Anvin
2010-09-09T21:02:55Z

On 09/09/2010 12:53 PM, Tomáš Janoušek wrote:
> Hello,
>
> 2.6.32.21 does not boot on my HP Compaq nx7300. I bisected it to this patch:
>
> On Mon, Aug 02, 2010 at 04:59:50PM -0700, Greg KH wrote:
>> On Mon, Aug 02, 2010 at 04:51:27PM -0700, Jeremy Fitzhardinge wrote:
>>> On 07/27/2010 10:33 PM, tip-bot for H. Peter Anvin wrote:
>>>> Commit-ID: 113fc5a6e8c2288619ff7e8187a6f556b7e0d372
>>>> Gitweb: http://git.kernel.org/tip/113fc5a6e8c2288619ff7e8187a6f556b7e0d372
>>>> Author: H. Peter Anvin<hpa@zytor.com>
>>>> AuthorDate: Tue, 27 Jul 2010 17:01:49 -0700
>>>> Committer: H. Peter Anvin<hpa@zytor.com>
>>>> CommitDate: Tue, 27 Jul 2010 17:14:02 -0700
>>>>
>>>> x86: Add memory modify constraints to xchg() and cmpxchg()
>>>
>>> Here's the 2.6.32 version for stable.
>>
>> Thanks, I'll queue it up when it hits Linus's tree.
>
> Here's a video of the crash: http://store.lisk.in/tmp/09092010019.mp4
> With boot_delay=30, it sometimes just reboots and sometimes prints the trace.
> Without it, it always prints the trace. The crash occurs during the
> initialization of intel-agp (which explains why I can't reproduce it in qemu).
> More details in the video.
>
> The system boots and works just fine with 2.6.32.21 with the patch reverted.
> v2.6.36-rc3-185-gd56557a works fine as well, perhaps there were other fixes
> that didn't get to stable (e.g. 4532b30).
>
> I'm compiling the kernel with the latest gcc in Debian (-dumpversion says
> 4.4.5, dpkg reports 4:4.4.4-2). Shall I post dmesg/lspci as well?
>
> Since I have an easy workaround and other things to do, I won't spend time
> trying to backport those other fixes myself, but if you're going to fix this,
> I will help with testing.
>

Could you give us your .config and also what version of gcc and binutils
is on your system?

-hpa