From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752168AbYCLGmf (ORCPT ); Wed, 12 Mar 2008 02:42:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750923AbYCLGm0 (ORCPT ); Wed, 12 Mar 2008 02:42:26 -0400 Received: from www262.sakura.ne.jp ([202.181.97.72]:55908 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750775AbYCLGmZ (ORCPT ); Wed, 12 Mar 2008 02:42:25 -0400 Message-Id: <200803120635.m2C6Zc03091406@www262.sakura.ne.jp> Subject: Re: [2.6.25-rc5-mm1] BUG() at mnt_want_write(). From: Tetsuo Handa To: Dave Hansen Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, Christoph Hellwig MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit Date: Wed, 12 Mar 2008 15:35:38 +0900 References: <200803120137.m2C1bffL037440@www262.sakura.ne.jp> <1205291010.9828.60.camel@nimitz.home.sr71.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello. I modified /usr/share/initrd-tools/init and tested. ----- start of patch ----- diff -u /usr/share/initrd-tools/init.org /usr/share/initrd-tools/init --- /usr/share/initrd-tools/init.org 2005-05-27 08:44:00.000000000 +0900 +++ /usr/share/initrd-tools/init 2008-03-12 15:14:31.000000000 +0900 @@ -359,7 +359,10 @@ read root < bin/root umount -n bin +echo "About to write real-root-dev" +echo "hello" > proc/version echo $root > proc/sys/kernel/real-root-dev +echo "Wrote real-root-dev" get_cmdline @@ -415,7 +418,9 @@ cd / mount -nt proc proc proc +echo "About to read real-root-dev" rootdev=$(cat proc/sys/kernel/real-root-dev) +echo "Read real-root-dev" cmdline=$(cat /proc/cmdline) umount -n proc if [ $rootdev != 256 ]; then ----- end of patch ----- The result was ----------------------------------------------------------------------------- initrd-tools: 0.1.81.1 do_sys_open: bin/root do_sys_open: /etc/ld.so.preload do_sys_open: /etc/ld.so.cache do_sys_open: /lib/tls/i686/mmx/cmov/libblkid.so.1 do_sys_open: /lib/tls/i686/mmx/libblkid.so.1 do_sys_open: /lib/tls/i686/cmov/libblkid.so.1 do_sys_open: /lib/tls/i686/libblkid.so.1 do_sys_open: /lib/tls/mmx/cmov/libblkid.so.1 do_sys_open: /lib/tls/mmx/libblkid.so.1 do_sys_open: /lib/tls/cmov/libblkid.so.1 do_sys_open: /lib/tls/libblkid.so.1 do_sys_open: /lib/i686/mmx/cmov/libblkid.so.1 do_sys_open: /lib/i686/mmx/libblkid.so.1 do_sys_open: /lib/i686/cmov/libblkid.so.1 do_sys_open: /lib/i686/libblkid.so.1 do_sys_open: /lib/mmx/cmov/libblkid.so.1 do_sys_open: /lib/mmx/libblkid.so.1 do_sys_open: /lib/cmov/libblkid.so.1 do_sys_open: /lib/libblkid.so.1 do_sys_open: /lib/tls/libuuid.so.1 do_sys_open: /lib/libuuid.so.1 do_sys_open: /lib/tls/libc.so.6 do_sys_open: /etc/mtab About to write real-root-dev do_sys_open: proc/version BUG: unable to handle kernel paging request at df366fe8 IP: [] mnt_want_write+0x41/0x5f *pde = 1f884163 *pte = 1f366160 Oops: 0002 [#1] SMP DEBUG_PAGEALLOC last sysfs file: Modules linked in: Pid: 1, comm: init Not tainted (2.6.25-rc5-mm1 #2) EIP: 0060:[] EFLAGS: 00010286 CPU: 0 EIP is at mnt_want_write+0x41/0x5f EAX: 00000000 EBX: c1453460 ECX: 00000001 EDX: df366f78 ESI: df363f78 EDI: 00000000 EBP: df8e1ef0 ESP: df8e1ee4 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 Process init (pid: 1, ti=df8e1000 task=df8f8020 task.ti=df8e1000) Stack: ffffffeb 00000200 df8e1f20 df8e1f7c c0173481 ffffa87b 00000000 ffffff9c c053481a 00008242 00000000 00000002 00008241 df363f78 df56cf50 df363f78 df56cf50 57b32ee9 00000007 df911005 00000300 00000000 00000000 c016a9ca Call Trace: [] ? do_filp_open+0x233/0x52f [] ? get_unused_fd_flags+0xb3/0xbe [] ? do_sys_open+0x50/0xd0 [] ? sys_open+0x16/0x18 [] ? syscall_call+0x7/0xb ======================= Code: 8d 1c 02 89 d8 e8 d3 b4 1c 00 89 f0 e8 7e ff ff ff 85 c0 74 07 bf e2 ff ff ff eb 1f 8b 53 2c 39 f2 74 15 85 d2 74 0e 8b 43 28 90 <01> 42 70 c7 43 28 00 00 00 00 89 73 2c ff 43 28 89 d8 e8 cf b5 EIP: [] mnt_want_write+0x41/0x5f SS:ESP 0068:df8e1ee4 ---[ end trace e13043ee7a72cd3f ]--- Kernel panic - not syncing: Attempted to kill init! ----------------------------------------------------------------------------- "proc/version" caused the same problem with "proc/sys/kernel/real-root-dev". And if I specify "bin/foo" instead of "proc/version", the result was ----------------------------------------------------------------------------- About to write real-root-dev do_sys_open: bin/foo /sbin/init: 363: cannot create bin/foo: Read-only file system do_sys_open: proc/sys/kernel/real-root-dev BUG: unable to handle kernel paging request at df379fe8 ----------------------------------------------------------------------------- So, no problem with accessing "bin/", but has problem with "proc/". Regards.