From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753947Ab0HCD0f (ORCPT ); Mon, 2 Aug 2010 23:26:35 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:49434 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753339Ab0HCD0e convert rfc822-to-8bit (ORCPT ); Mon, 2 Aug 2010 23:26:34 -0400 To: Dave Airlie Cc: Yinghai Lu , LKML , Ingo Molnar Subject: Re: oops in ioapic_write_entry References: From: ebiederm@xmission.com (Eric W. Biederman) Date: Mon, 02 Aug 2010 20:26:29 -0700 In-Reply-To: (Dave Airlie's message of "Tue\, 3 Aug 2010 09\:17\:16 +1000") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT X-XM-SPF: eid=;;;mid=;;;hst=in02.mta.xmission.com;;;ip=67.188.4.80;;;frm=ebiederm@xmission.com;;;spf=neutral X-SA-Exim-Connect-IP: 67.188.4.80 X-SA-Exim-Mail-From: ebiederm@xmission.com X-SA-Exim-Scanned: No (on in02.mta.xmission.com); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dave Airlie writes: >> >> the kernel is using mptable, and the  system have mcp55, so how come >> with irq 35? >> assume we should only have ioapic irq 0 - 23 ... >> >> Can you send out boot log with "debug apic=debug pci=routeirq" with >> 2.6.32 and 2.6.35? > > Okay el6log is from a RHEL6 2.6.32 kernel, but it should give a good > baseline, the 2.6.35 oops even earlier with all those options and is > in the second attachment. It appears we have a smoking gun: For some reason setup_IO_APIC_IRQS thinks we at least 2 io_apics, but we have only setup 1 io_apic. Since io_apics need a kmap entry accessing an apic that hasn't been setup will definitely give a page fault. It sounds like something is stomping nr_ioapics. From: 2.6.35-debuglog IOAPIC[0]: apic_id 8, version 17, address 0xfec00000, GSI 0-23 .... IOAPIC[1]: Set routing entry (0-16 -> 0x51 -> IRQ 16 Mode:1 Active:1) Can we get your System.map of the failing kernel (so we can see what is close to nr_ioapics), and could you add a print statement in arch/x86/kernel/apic/io_apic:setup_IO_APIC_irqs to print nr_ioapics? I would be surprised if drm changes could have affected this. Eric