Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754799AbZDMXmu (ORCPT ); Mon, 13 Apr 2009 19:42:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753519AbZDMXmh (ORCPT ); Mon, 13 Apr 2009 19:42:37 -0400 Received: from mx2.redhat.com ([66.187.237.31]:45462 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753066AbZDMXmg (ORCPT ); Mon, 13 Apr 2009 19:42:36 -0400 Date: Mon, 13 Apr 2009 17:41:05 -0600 From: Pete Zaitcev To: "John Stoffel" Cc: Jarek Poplawski , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-usb@vger.kernel.org, zaitcev@redhat.com Subject: Re: usb_mon oops Re: tcpdump crashes 2.6.29.1 (and 2.6.29-rc5) Message-Id: <20090413174105.b03a1f19.zaitcev@redhat.com> In-Reply-To: <18909.65347.234817.29689@stoffel.org> References: <18906.49779.243047.207639@stoffel.org> <20090407120022.GA6519@ff.dom.local> <18907.28788.965069.573489@stoffel.org> <20090407130403.e0061a8d.zaitcev@redhat.com> <18908.42166.404232.721757@stoffel.org> <20090408232344.afed8103.zaitcev@redhat.com> <18909.65347.234817.29689@stoffel.org> Organization: Red Hat, Inc. Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1444 Lines: 36 On Thu, 9 Apr 2009 09:59:31 -0400, "John Stoffel" wrote: > Here's a dmesg of bootup: > [ 0.000000] Linux version 2.6.29.1 (john@sail) (gcc version 4.3.3 (Ubuntu 4.3.3-5ubuntu4) ) #24 SMP PREEMPT Tue Apr 7 11:30:52 EDT 2009 > [ 0.000999] Checking aperture... > [ 0.000999] No AGP bridge found > [ 0.000999] Node 0: aperture @ 20000000 size 32 MB > [ 0.000999] Aperture pointing to e820 RAM. Ignoring. > [ 0.000999] Your BIOS doesn't leave a aperture memory hole > [ 0.000999] Please enable the IOMMU option in the BIOS setup > [ 0.000999] This costs you 64 MB of RAM > [ 0.000999] Mapping aperture over 65536 KB of RAM @ 20000000 > [ 1396.271782] BUG: unable to handle kernel paging request at ffff880020a15cc0 So 20a15000 is in the aperture. Oh well, I screwed up. I meant to check for this back in 2006 but forgot, and miraclously it worked until now. Here's the problem: pg = phys_to_page(dma_addr); map = kmap_atomic(pg, KM_IRQ0); offset = mon_copy_to_buff(rp, offset, map + page_off, step_len); kunmap_atomic(map, KM_IRQ0); Obviously we don't want the page that's overlayed by the aperture, but the page where IOMMU is pointing. -- Pete -- 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/