From: Ingo Molnar <mingo@elte.hu>
Subject: Re: 2.6.25-git2: BUG: unable to handle kernel paging request at
	ffffffffffffffff
Date: Mon, 21 Apr 2008 15:17:43 +0200
Message-ID: <20080421131741.GI9554@elte.hu>
References: <200804191522.54334.rjw@sisk.pl> <200804202104.24037.rjw@sisk.pl>
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Cc: LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-ext4@vger.kernel.org
To: "Rafael J. Wysocki" <rjw@sisk.pl>
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* Rafael J. Wysocki <rjw@sisk.pl> wrote:

> Hi,
> 
> I've just got the following traces from 2.6.25-git2 on HP nx6325 
> (64-bit). I think they are related to the hang I described yesterday:

> [12844.112673]  [<ffffffff8029e236>] do_lookup+0x2c/0x1b2
> [12844.112683]  [<ffffffff802a04b4>] __link_path_walk+0x8e6/0xdbd
> [12844.112707]  [<ffffffffa004deb4>] ? :ext3:ext3_xattr_get_acl_default+0x18/0x1a
> [12844.112714]  [<ffffffff802b0869>] ? generic_getxattr+0x4e/0x5c

so you've got ext3. Nothing changed in the VFS or in ext3 in -git yet.

the instruction pattern:

Code: f6 43 04 10 75 06 f0 ff 03 48 89 d8 fe 43 08 eb 31 fe 43 08 48 8b 
45 d0 48 8b 00 48 89 45 d0 48 8b 45 d0 48 85 c0 74 18 48 89 c2 <48> 8b 
00 48 8d 5a e8 44 39 73 30 0f 18 08 75 d9 e9 6a ff ff ff
                           ========

shows that you've got "prefetchnta (%esi)" indirect:

   0f 18 00                prefetcht0 (%eax)

so the prefetch instructions are patched in, neither the compiler nor 
the CPU should ignore them.

	Ingo