linux-kernel - Re: Intel BIOS - Corrupted low memory at ffff880000004200

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Date:	Fri, 10 Jul 2009 16:04:12 +0200
From:	Alexey Fisher <bug-track@...her-privat.net>
To:	Thomas Gleixner <tglx@...utronix.de>
CC:	Ingo Molnar <mingo@...e.hu>, Matthew Garrett <mjg59@...f.ucam.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Arjan van de Ven <arjan@...radead.org>,
	"Pallipadi, Venkatesh" <venkatesh.pallipadi@...el.com>,
	Yinghai Lu <yinghai@...nel.org>,
	Suresh Siddha <suresh.b.siddha@...el.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Kernel Testers List <kernel-testers@...r.kernel.org>,
	"Richard A. Holden III" <aciddeath@...il.com>
Subject: Re: Intel BIOS - Corrupted low memory at ffff880000004200

Thomas Gleixner schrieb:
> On Fri, 10 Jul 2009, Alexey Fisher wrote:
>> Ingo Molnar schrieb:
>>> * Matthew Garrett <mjg59@...f.ucam.org> wrote:
>>>
>>>> On Mon, Jul 06, 2009 at 06:24:47PM +0200, Alexey Fisher wrote:
>>>>> Hallo Ingo, Richard.
>>>>>
>>>>> I'm getting "Corrupted low memory" trace with my Intel DG45ID board
>>>>> after resume. This board has different dmi-bios-vendor... so probably it
>>>>> will be nice to have it in your patch.
>>>> I'm beginning to think that we should be doing this on all hardware,
>>>> perhaps with a kernel option to disable it for embedded devices that
>>>> really need that 64K. The low-memory corruption issue seems to be very
>>>> widespread.
>>> The problem is that the BIOS corrupted memory that it also marked as
>>> 'usable' in its E820 map it gave to the kernel. If that memory is not
>>> usable, it should not have been marked as such. Also, some of the reports
>>> showed corruption beyond this range so the workaround is not universal.
>>>
>>> So i'd really like to know what is happening there, instead of just zapping
>>> support for 64K of RAM on the majority of Linux systems.
>>>
>>> We might end up doing the same thing in the end (i.e. disable that 64k of
>>> RAM) - but it should be an informed decision, not a wild stab in the dark.
>>>
>>> 	Ingo
>> If i make memory dump like "dd if=/dev/mem of=memdump.dd bs=64k count=1"
>> before and after suspend. Will it help you find out whats happening.
> 
> The corrupted low memory printks contain the modifications. Can you
> post them please ?
> 
> Thanks,
> 
> 	tglx

[  120.816090] Corrupted low memory at ffff880000004200 (4200 phys) = 
00420301
[  120.816095] ------------[ cut here ]------------
[  120.816102] WARNING: at arch/x86/kernel/check.c:134 
check_for_bios_corruption+0xe4/0xf0()
[  120.816104] Hardware name:
[  120.816106] Memory corruption detected in low memory
[  120.816107] Modules linked in: binfmt_misc kvm_intel kvm 
snd_hda_codec_intelhdmi snd_hda_codec_idt snd_hda_intel snd_hda_codec 
snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_dummy snd_seq_oss snd_seq_midi 
snd_rawmidi snd_seq_midi_event snd_seq snd_timer snd_seq_device psmouse 
snd serio_raw iTCO_wdt iTCO_vendor_support soundcore snd_page_alloc e1000e
[  120.816129] Pid: 9, comm: events/0 Tainted: G        W 
2.6.31-rc1-25446-g1ae8c0a-dirty #2
[  120.816131] Call Trace:
[  120.816136]  [<ffffffff8104a8e8>] warn_slowpath_common+0x78/0xb0
[  120.816139]  [<ffffffff8104a97c>] warn_slowpath_fmt+0x3c/0x40
[  120.816142]  [<ffffffff8102aff4>] check_for_bios_corruption+0xe4/0xf0
[  120.816146]  [<ffffffff8102b000>] ? check_corruption+0x0/0x30
[  120.816148]  [<ffffffff8102b009>] check_corruption+0x9/0x30
[  120.816152]  [<ffffffff8105e4d4>] worker_thread+0x144/0x260
[  120.816155]  [<ffffffff810635c0>] ? autoremove_wake_function+0x0/0x40
[  120.816158]  [<ffffffff8105e390>] ? worker_thread+0x0/0x260
[  120.816161]  [<ffffffff810631e6>] kthread+0x96/0xa0
[  120.816165]  [<ffffffff8100c69a>] child_rip+0xa/0x20
[  120.816168]  [<ffffffff81063150>] ? kthread+0x0/0xa0
[  120.816171]  [<ffffffff8100c690>] ? child_rip+0x0/0x20
[  120.816173] ---[ end trace 11e2979285be7426 ]---


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