lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date:	Mon, 11 Nov 2013 16:04:13 -0800
From:	"H. Peter Anvin" <hpa@...ux.intel.com>
To:	Ingo Molnar <mingo@...nel.org>
CC:	Olof Johansson <olof@...om.net>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Corrupted low memory in v3.9+

On 11/11/2013 03:31 PM, H. Peter Anvin wrote:
> On 11/11/2013 03:35 AM, Ingo Molnar wrote:
> 
> Oops!  I had misunderstood how the checker worked -- I thought it
> checked the *reserved* memory, but it in fact reserves memory
> *independently* and then checks it.
> 

And now I understand why I had that misconception:

> 	  Periodically check for memory corruption in low memory, which
> 	  is suspected to be caused by BIOS.  Even when enabled in the
> 	  configuration, it is disabled at runtime.  Enable it by
> 	  setting "memory_corruption_check=1" on the kernel command
> 	  line.  By default it scans the low 64k of memory every 60
> 	  seconds; see the memory_corruption_check_size and
> 	  memory_corruption_check_period parameters in
> 	  Documentation/kernel-parameters.txt to adjust this.

This makes it sound like it scans the low 64K when it is turned on, i.e.
the bit that is reserved by default.

I think we should change that default too to 640K.  I will post a
patchset shortly.

	-hpa



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists