Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755074AbYG0KIJ (ORCPT ); Sun, 27 Jul 2008 06:08:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751205AbYG0KH4 (ORCPT ); Sun, 27 Jul 2008 06:07:56 -0400 Received: from py-out-1112.google.com ([64.233.166.180]:61580 "EHLO py-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751194AbYG0KHz (ORCPT ); Sun, 27 Jul 2008 06:07:55 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=RUbQ3g5aBXVpOrY7eF5S3MTOzZ31cijdN6lL41vFwDmXfZ2e7tfcKEKuS5gi0BLo08 QuAGbqNUFlPupwkpsZkrIwZyMagW8cipxLL2+2m8Ro0giJy6L2KcmwZlX3oVPqxlksF3 tpShkGnefDmWmcyk6uW+oWQU82X60kwdPTvuo= Message-ID: <19f34abd0807270307p505568b8nf871162d89b002ef@mail.gmail.com> Date: Sun, 27 Jul 2008 12:07:54 +0200 From: "Vegard Nossum" To: lkml Subject: Re: -git: BUG: unable to handle kernel paging request at c0100248 [CPU hotplug] Cc: "Thomas Meyer" , "Dmitry Adamushko" , "the arch/x86 maintainers" , "Glauber Costa" , "Ingo Molnar" In-Reply-To: <19f34abd0807270255o1ff260a8ucb9d931905aa4947@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <19f34abd0807270255o1ff260a8ucb9d931905aa4947@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1863 Lines: 58 On Sun, Jul 27, 2008 at 11:55 AM, Vegard Nossum wrote: > Hi, > > Something broke CPU-hotplug _again_, here with a freshly built latest -git: > > BUG: unable to handle kernel paging request at c0100248 [snip] > c067c3db: c7 05 48 02 10 c0 f0 movl $0xc067c9f0,0xc0100248 > c067c3e2: c9 67 c0 > > $ addr2line -e vmlinux -i c067c3db > arch/x86/kernel/smpboot.c:859 > arch/x86/kernel/smpboot.c:993 > > Hm... that doesn't really make sense, does it? It's this line: > > initial_code = (unsigned long)start_secondary; > > ..but I don't see where the memory dereference comes from. "initial_code" (0xc0100248) is in a .text section: Idx Name Size VMA LMA File off Algn 0 .text.head 000003a1 c0100000 00100000 00001000 2**2 1 .text 00583b8d c01003b0 001003b0 000013b0 2**4 And I have CONFIG_DEBUG_RODATA=y. Maybe this was introduced in commit e3f77edfc1d0beb7b10f9f31d9e39206f7dbef7b Author: Glauber Costa Date: Wed May 28 12:57:02 2008 -0300 x86: use initial_code for i386 x86_64 jumps to whatever is written in "initial_code" symbol, instead of a fixed address. Do it for i386 too. It will allow us to integrate more of the smp boot code. Signed-off-by: Glauber Costa Signed-off-by: Ingo Molnar ? Vegard -- "The animistic metaphor of the bug that maliciously sneaked in while the programmer was not looking is intellectually dishonest as it disguises that the error is the programmer's own creation." -- E. W. Dijkstra, EWD1036 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/