linux-ext4 - Re: 2.6.25-git2: BUG: unable to handle kernel paging request at ffffffffffffffff

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] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.LFD.1.10.0804241841280.2779@woody.linux-foundation.org>
Date:	Thu, 24 Apr 2008 18:48:32 -0700 (PDT)
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	David Miller <davem@...emloft.net>
cc:	jirislaby@...il.com, zdenek.kabelac@...il.com, mingo@...e.hu,
	rjw@...k.pl, paulmck@...ux.vnet.ibm.com,
	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	linux-ext4@...r.kernel.org, herbert@...dor.apana.org.au,
	penberg@...helsinki.fi, clameter@....com
Subject: Re: 2.6.25-git2: BUG: unable to handle kernel paging request at
 ffffffffffffffff

On Thu, 24 Apr 2008, David Miller wrote:
> 
> So the clue is setting some byte at ((offset % 8) == 0) into a
> structure with 0xf0...

It's not always at (offset % 8) == 0. We've seen that 0xf0 pattern in 
other oopses, but it's not always 8-byte aligned. In fact, when we've seen 
it in oopses, it has generally been in the higher bytes (eg offset 5 
within a 64-bit word, causing an invalid pointer on x86-64).

But that 0xf0 definitely has shown up before. It's not the *only* 
corruption, but it's definitely a very interesting pattern. And the other 
ones that didn't show the 0xf0 pattern could obviously be due to pointers 
that were corrupted by 0xf0 in low bytes, so it _may_ be the source of the 
other corruptions too that didn't have an obvious 0xf0 directly in them.

			Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html