From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261391AbVBRPfW (ORCPT ); Fri, 18 Feb 2005 10:35:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261389AbVBRPfW (ORCPT ); Fri, 18 Feb 2005 10:35:22 -0500 Received: from ppsw-4.csi.cam.ac.uk ([131.111.8.134]:17027 "EHLO ppsw-4.csi.cam.ac.uk") by vger.kernel.org with ESMTP id S261387AbVBRPfI (ORCPT ); Fri, 18 Feb 2005 10:35:08 -0500 Subject: Re: [uml-devel] [BUG: UML 2.6.11-rc4-bk-latest] sleeping function called from invalid context and segmentation fault From: Anton Altaparmakov To: Blaisorblade Cc: user-mode-linux-devel@lists.sourceforge.net, Jeff Dike , lkml In-Reply-To: <200502161935.43820.blaisorblade@yahoo.it> References: <1108381733.10703.5.camel@imp.csi.cam.ac.uk> <200502161935.43820.blaisorblade@yahoo.it> Content-Type: text/plain Organization: University of Cambridge Computing Service, UK Date: Fri, 18 Feb 2005 15:33:43 +0000 Message-Id: <1108740823.6713.28.camel@imp.csi.cam.ac.uk> Mime-Version: 1.0 X-Mailer: Evolution 2.0.1 Content-Transfer-Encoding: 7bit X-Cam-ScannerInfo: http://www.cam.ac.uk/cs/email/scanner/ X-Cam-AntiVirus: No virus found X-Cam-SpamDetails: Not scanned Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2005-02-16 at 19:35 +0100, Blaisorblade wrote: > On Monday 14 February 2005 12:48, Anton Altaparmakov wrote: > > Hi, > > > > I get a few Debug messages of the form from UML: > > > > Debug: sleeping function called from invalid context at > > include/asm/arch/semaphore.h:107 > > in_atomic():0, irqs_disabled():1 > > Call Trace: > > 087d77b0: [<0809aaa5>] __might_sleep+0x135/0x180 > > 087d77d8: [<084d377f>] mcount+0xf/0x20 > > 087d77e0: [<0807cc13>] uml_console_write+0x33/0x80 > > > Most are coming via uml_console_write. > The problem is that the UML tty drivers use a semaphore instead of a spinlock > for the locking, which also causes some other problems. > > The attached patch should fix this, but I've not yet made sure it is not > deadlock-prone (I didn't hit any during some very limited testing). > > So it's not yet ready for 2.6.11. Trying with the above patch in now only get two "sleeping function called from invalid context" warnings during boot and none during running. However I get a lot of those errors: arch/um/drivers/line.c:262: spin_lock(arch/um/drivers/line.c:085b5900) already locked by arch/um/drivers/line.c/262 Also both before and after the patch I see a lot of messages like: kernel: line_write_room: tty2: no room left in buffer Best regards, Anton -- Anton Altaparmakov (replace at with @) Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK Linux NTFS maintainer / IRC: #ntfs on irc.freenode.net WWW: http://linux-ntfs.sf.net/ & http://www-stu.christs.cam.ac.uk/~aia21/