From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: Re: [Bugme-new] [Bug 8940] New: BUG: unable to handle kernel NULL pointer dereference at virtual address 00000000 Date: Sun, 26 Aug 2007 07:57:45 -0600 Message-ID: <20070826135745.GE14130@parisc-linux.org> References: <20070826005207.4f0b62ce.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from palinux.external.hp.com ([192.25.206.14]:49108 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751142AbXHZN5q (ORCPT ); Sun, 26 Aug 2007 09:57:46 -0400 Content-Disposition: inline In-Reply-To: <20070826005207.4f0b62ce.akpm@linux-foundation.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Andrew Morton Cc: linux-scsi@vger.kernel.org, linux-usb-devel@lists.sourceforge.net, bugme-daemon@bugzilla.kernel.org, dchris@gmail.com On Sun, Aug 26, 2007 at 12:52:07AM -0700, Andrew Morton wrote: > On Sat, 25 Aug 2007 09:47:40 -0700 (PDT) bugme-daemon@bugzilla.kernel.org wrote: > > Problem Description: I got this error message: > > BUG: unable to handle kernel NULL pointer dereference at virtual address > > 00000000 > > in dmesg output when connecting a USB device. Turning off > > CONFIG_SCSI_SCAN_ASYNC fixed the problem. Apparently there is a bug in SCSI > > core code. I don't think SCSI_SCAN_ASYNC is the problem. It's probably a coincidence. SCSI_SCAN_ASYNC doesn't touch the call-path reported in the backtrace. In any case, if it is SCSI_SCAN_ASYNC-related, there's an outstanding patch to fix the locking, which is slated for inclusion in 2.6.24. http://git.kernel.org/?p=linux/kernel/git/jejb/scsi-misc-2.6.git;a=commit;h=a93a091df8232fad60867d41fbc3be855a0b78f2 -- "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."