From: Li Zefan Subject: [ext4 BUG?] task pdflush:3880 blocked for more than 120 seconds Date: Mon, 06 Oct 2008 11:00:59 +0800 Message-ID: <48E97F6B.9060409@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org, LKML To: "Theodore Ts'o" Return-path: Received: from cn.fujitsu.com ([222.73.24.84]:56010 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751835AbYJFDBZ (ORCPT ); Sun, 5 Oct 2008 23:01:25 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: This bug exists both in mainline and ext4-patch-queue. Procedures to reproduce it: 1. mkfs.ext4dev -I 256 -b 4096 -O extents /dev/sdb1 2. mount -t ext4dev -o delalloc /dev/sdb1 mnt_point/ 3. run ffsb until filesystem is full and ffsb exits with failure 4. umount mnt_point And then umount stuck at D state. The output of ps: 3873 ? D< 0:07 [kjournald2] 3880 ? D 0:00 [pdflush] 3885 ? S 0:00 [pdflush] 3944 ? S 0:00 [pdflush] 3957 ? S 0:00 [pdflush] 3962 ? S 0:00 [pdflush] 3974 ? S 0:00 [pdflush] 3975 ? S 0:00 [pdflush] 3979 pts/1 D+ 0:01 umount mnt_point dmesg: EXT4-fs: barriers enabled kjournald2 starting. Commit interval 5 seconds EXT4 FS on sdb1, internal journal on sdb1:8 EXT4-fs: mounted filesystem with ordered data mode. EXT4-fs: delayed allocation enabled EXT4-fs: file extents enabled EXT4-fs: mballoc enabled ffsb[3888]: segfault at 8 ip 0000003878832dc7 sp 00000000425f5fa0 error 4 in libc-2.5.so[3878800000+146000] INFO: task pdflush:3880 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. pdflush D ffff88013c6eb700 0 3880 2 ffff88009a623df0 0000000000000046 0000000000000000 ffffffff80254c20 ffff8800bfa63040 ffff8800bfa63040 ffff88013faf3040 ffff8800bfa63398 00000002bfa63040 000000010009baab ffffffffffffffff ffffffffffffffff Call Trace: [] __lock_acquire+0x6ad/0x716 [] __down_read+0x7e/0x96 [] sync_supers+0x3f/0xb3 [] sync_supers+0x3f/0xb3 [] pdflush+0x0/0x207 [] wb_kupdate+0x2d/0x10d [] pdflush+0x0/0x207 [] pdflush+0x0/0x207 [] pdflush+0x156/0x207 [] wb_kupdate+0x0/0x10d [] kthread+0x47/0x74 [] trace_hardirqs_on_thunk+0x3a/0x3f [] child_rip+0xa/0x11 [] restore_args+0x0/0x30 [] kthread+0x0/0x74 [] child_rip+0x0/0x11 1 lock held by pdflush/3880: #0: (&type->s_umount_key#21){----}, at: [] sync_supers+0x3f/0xb3 INFO: task pdflush:3880 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. pdflush D ffff88013c6eb700 0 3880 2 ffff88009a623df0 0000000000000046 0000000000000000 ffffffff80254c20 ffff8800bfa63040 ffff8800bfa63040 ffff88013faf3040 ffff8800bfa63398 00000002bfa63040 000000010009baab ffffffffffffffff ffffffffffffffff Call Trace: [] __lock_acquire+0x6ad/0x716 [] __down_read+0x7e/0x96 [] sync_supers+0x3f/0xb3 [] sync_supers+0x3f/0xb3 [] pdflush+0x0/0x207 [] wb_kupdate+0x2d/0x10d [] pdflush+0x0/0x207 [] pdflush+0x0/0x207 [] pdflush+0x156/0x207 [] wb_kupdate+0x0/0x10d [] kthread+0x47/0x74 [] trace_hardirqs_on_thunk+0x3a/0x3f [] child_rip+0xa/0x11 [] restore_args+0x0/0x30 [] kthread+0x0/0x74 [] child_rip+0x0/0x11 1 lock held by pdflush/3880: #0: (&type->s_umount_key#21){----}, at: [] sync_supers+0x3f/0xb3