Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751788AbWJMSKg (ORCPT ); Fri, 13 Oct 2006 14:10:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751789AbWJMSKg (ORCPT ); Fri, 13 Oct 2006 14:10:36 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:37132 "HELO iolanthe.rowland.org") by vger.kernel.org with SMTP id S1751788AbWJMSKf (ORCPT ); Fri, 13 Oct 2006 14:10:35 -0400 Date: Fri, 13 Oct 2006 14:10:34 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Helge Hafting , Andrew Morton cc: Kernel development list , USB development list Subject: Re: [linux-usb-devel] 2.6.19-rc1-mm1 - locks when using "dd bs=1M" from card reader In-Reply-To: <20061013092941.30500a15.akpm@osdl.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1964 Lines: 54 On Fri, 13 Oct 2006, Andrew Morton wrote: > On Fri, 13 Oct 2006 15:11:11 +0200 > Helge Hafting wrote: > > > Andrew Morton wrote: > > > On Thu, 12 Oct 2006 14:18:04 +0200 > > > Helge Hafting wrote: > > > > > > > > >> I found an easy way to hang the kernel when copying a SD-card: > > >> > > >> dd if=/dev/sdc of=file bs=1048576 > > >> > > >> I.e. copy the entire 256MB card in 1MB chunks. I got about > > >> 160MB before the kernel hung. Not even sysrq+B worked, I needed > > >> the reset button. The pc has a total of 512MB memory if that matters. > > >> > > >> Using bs=4096 instead let me copy the entire card with no problems, > > >> but that seems to progress slower. > > >> > > >> The above 'dd' command hangs my office pc every time. So I can repeat > > >> it for debugging purposes. > > >> > > >> > > > > > > What device driver is providing /dev/sdc? > > > > > It is an usb card reader, so it is "usb mass storage" > > and "scsi disk". > > > Did any previous kernels work correctly? If so, which? > > > > > > > I just got that card reader, so I haven't tested any earlier kernels. > > I have another machine with a card reader, which I have used for > > a long time. But I only ever copy files with "cp" on that one. > > > > This time I used "dd" to get an image of the entire card, and got trouble > > when using 1M chunks. > > > > I can try with verbose scsi debug messages if that might help? Verbose usb-storage debugging messages would help more (CONFIG_USB_STORAGE_DEBUG and CONFIG_USB_DEBUG). If the kernel hangs very badly you might need to use a serial console to capture all the logging information. Alan Stern - 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/