Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760211AbXEJAVE (ORCPT ); Wed, 9 May 2007 20:21:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756894AbXEJAUx (ORCPT ); Wed, 9 May 2007 20:20:53 -0400 Received: from gw.goop.org ([64.81.55.164]:37080 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756827AbXEJAUw (ORCPT ); Wed, 9 May 2007 20:20:52 -0400 Message-ID: <4642656B.9020501@goop.org> Date: Wed, 09 May 2007 17:20:59 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 1.5.0.10 (X11/20070302) MIME-Version: 1.0 To: Andrew Morton CC: Ken Chen , Peter Zijlstra , Linux Kernel Mailing List , Kay Sievers , Alexey Dobriyan Subject: Re: 2.6.21-git11: BUG in loop.ko References: <46425EC9.5070209@goop.org> <20070509170521.ec2c9ae7.akpm@linux-foundation.org> In-Reply-To: <20070509170521.ec2c9ae7.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3614 Lines: 93 Andrew Morton wrote: > On Wed, 09 May 2007 16:52:41 -0700 > Jeremy Fitzhardinge wrote: > > >> Seems to be getting a 0 refcount. I don't see anything in the recent >> changes which might cause this, but this is relatively new behaviour. >> It was working for me in the 2.6.21-pre time period, but I haven't tried >> this since 2.6.21 was released. >> >> The BUG is actually triggered by the __module_get(THIS_MODULE) in >> loop_set_fd. >> >> J >> >> loop: module loaded >> device-mapper: ioctl: 4.11.0-ioctl (2006-10-12) initialised: dm-devel@redhat.com >> ------------[ cut here ]------------ >> kernel BUG at /home/jeremy/hg/xen/paravirt/linux/include/linux/module.h:396! >> invalid opcode: 0000 [#1] >> PREEMPT SMP >> Modules linked in: dm_snapshot dm_mod loop >> CPU: 1 >> EIP: 0061:[] Not tainted VLI >> EFLAGS: 00010246 (2.6.21-paravirt #1339) >> EIP is at lo_ioctl+0x65/0xa52 [loop] >> eax: 00000000 ebx: cfb92c98 ecx: d085e480 edx: 00000200 >> esi: 00004c00 edi: cf8ad428 ebp: cf37fdc0 esp: cf37fbf8 >> ds: 007b es: 007b fs: 00d8 gs: 0033 ss: 0069 >> Process losetup (pid: 440, ti=cf37e000 task=cf30b4d0 task.ti=cf37e000) >> Stack: c1390080 c1390080 cf37fc10 00000008 cf8ad428 cfbb2258 00000000 cf37fc34 >> c01458c5 cfb92c98 c1392a40 cf30ba70 cf30b4d0 cf30ba54 00000002 cf30ba70 >> cf30b4d0 cf30ba54 00000002 00000003 c134c088 c134c088 cf37fc90 c01215b8 >> Call Trace: >> [] show_trace_log_lvl+0x1a/0x30 >> [] show_stack_log_lvl+0x9d/0xa5 >> [] show_registers+0x1f7/0x336 >> [] die+0x119/0x21b >> [] do_trap+0x8a/0xa4 >> [] do_invalid_op+0x88/0x92 >> [] error_code+0x72/0x78 >> [] blkdev_driver_ioctl+0x4c/0x5d >> [] blkdev_ioctl+0x754/0x7a2 >> [] block_ioctl+0x1b/0x1f >> [] do_ioctl+0x22/0x68 >> [] vfs_ioctl+0x232/0x245 >> [] sys_ioctl+0x49/0x63 >> [] syscall_call+0x7/0xb >> ======================= >> Code: ff 83 f8 06 0f 87 5a 09 00 00 ff 24 85 5c bc 85 d0 8b 9b cc 01 00 00 b8 80 e4 85 d0 89 9d 5c fe ff ff e8 37 0a 8f ef 85 c0 75 04 <0f> 0b eb fe b8 01 00 00 00 e8 79 9f 8c ef e8 ec 4b 9c ef c1 e0 >> EIP: [] lo_ioctl+0x65/0xa52 [loop] SS:ESP 0069:cf37fbf8 >> >> > > A few people have been playing with module refcounting lately. Did you > work out a reproduce-it recipe? > 100% reliable, but a bit obscure. I'm booting an FC6 livecd with a paravirt_ops kernel under Xen. The relevant part of the iso's initrd script is: + mknod /dev/loop118 b 7 118 + mknod /dev/loop119 b 7 119 + mknod /dev/loop120 b 7 120 + mknod /dev/loop121 b 7 121 + mkdir -p /dev/mapper + mknod /dev/mapper/control c 10 63 + modprobe loop max_loop=128 loop: the max_loop option is obsolete and will be removed in March 2008 loop: module loaded + modprobe dm_snapshot device-mapper: ioctl: 4.11.0-ioctl (2006-10-12) initialised: dm-devel@redhat.com + '[' 0 == 1 ']' + losetup /dev/loop120 /sysroot/squashfs.img ------------[ cut here ]------------ kernel BUG at /home/jeremy/hg/xen/paravirt/linux/include/linux/module.h:396! invalid opcode: 0000 [#1] PREEMPT SMP Modules linked in: dm_snapshot dm_mod loop CPU: 0 EIP: 0061:[] Not tainted VLI EFLAGS: 00010246 (2.6.21-paravirt #1339) [...] J - 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/