From: Pekka Enberg <penberg@cs.helsinki.fi>
To: mingo@elte.hu
Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org
Subject: Re: [PATCH] init: setup traps before mem_init()
Date: Thu, 11 Jun 2009 19:28:57 +0300 [thread overview]
Message-ID: <1244737737.6281.8.camel@penberg-laptop> (raw)
In-Reply-To: <Pine.LNX.4.64.0906111622510.13992@melkki.cs.Helsinki.FI>
On Thu, 2009-06-11 at 16:25 +0300, Pekka J Enberg wrote:
> From: Pekka Enberg <penberg@cs.helsinki.fi>
>
> 32-bit x86 does WP protect test in mem_init() so we must setup traps before we
> call mem_init() during boot. This patch should fix the following bug
> reported by Ingo Molnar:
>
> We have a hard crash in the WP-protect code:
>
> [ 0.000000] Checking if this processor honours the WP bit even in supervisor mode...BUG: Int 14: CR2 ffcff000
> [ 0.000000] EDI 00000188 ESI 00000ac7 EBP c17eaf9c ESP c17eaf8c
> [ 0.000000] EBX 000014e0 EDX 0000000e ECX 01856067 EAX 00000001
> [ 0.000000] err 00000003 EIP c10135b1 CS 00000060 flg 00010002
> [ 0.000000] Stack: c17eafa8 c17fd410 c16747bc c17eafc4 c17fd7e5 000011fd f8616000 c18237cc
> [ 0.000000] 00099800 c17bb000 c17eafec c17f1668 000001c5 c17f1322 c166e039 c1822bf0
> [ 0.000000] c166e033 c153a014 c18237cc 00020800 c17eaff8 c17f106a 00020800 01ba5003
> [ 0.000000] Pid: 0, comm: swapper Not tainted 2.6.30-tip-02161-g7a74539-dirty #52203
> [ 0.000000] Call Trace:
> [ 0.000000] [<c15357c2>] ? printk+0x14/0x16
> [ 0.000000] [<c10135b1>] ? do_test_wp_bit+0x19/0x23
> [ 0.000000] [<c17fd410>] ? test_wp_bit+0x26/0x64
> [ 0.000000] [<c17fd7e5>] ? mem_init+0x1ba/0x1d8
> [ 0.000000] [<c17f1668>] ? start_kernel+0x164/0x2f7
> [ 0.000000] [<c17f1322>] ? unknown_bootoption+0x0/0x19c
> [ 0.000000] [<c17f106a>] ? __init_begin+0x6a/0x6f
>
> Reported-by: Ingo Molnar <mingo@elte.hu>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
OK, I tested this on 32-bit and it works just fine.
Pekka
prev parent reply other threads:[~2009-06-11 16:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-11 13:25 Pekka J Enberg
2009-06-11 16:28 ` Pekka Enberg [this message]
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