Hi, There seems to be a bug in the ext2 implementation (in vanilla 3.3.4) where operations on a corrupted ext2 filesystem cause a hung task: 1. wget http://sli.dy.fi/~sliedes/berserker/testcases/ext2.110.min.bz2 2. mount ... /mnt -t ext2 -o errors=continue 3. Do some operations; what I do (it's the rm that crashes): timeout 30 cp -r doc doc2 >&/dev/null timeout 30 find -xdev >&/dev/null timeout 30 find -xdev -print0 2>/dev/null |xargs -0 touch -- 2>/dev/null timeout 30 mkdir tmp >&/dev/null timeout 30 echo whoah >tmp/filu 2>/dev/null timeout 30 rm -rf /mnt/* >&/dev/null 4. The rm task hangs The filesystem in fact differs from a pristine, fully working ext2 filesystem by only one bit: ------------------------------------------------------------ $ diff -u <(hd testimg.ext2) <(hd testimg.ext2.110.min) --- /dev/fd/63 2012-05-05 04:26:49.972546154 +0300 +++ /dev/fd/62 2012-05-05 04:26:49.972546154 +0300 @@ -13520,7 +13520,7 @@ 00902c90 73 64 65 31 00 00 00 00 00 00 00 00 00 00 00 00 |sde1............| 00902ca0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * -00903000 1d 05 00 00 0c 00 01 02 2e 00 00 00 29 00 00 00 |............)...| +00903000 1d 05 00 00 0c 00 01 02 6e 00 00 00 29 00 00 00 |........n...)...| 00903010 0c 00 02 02 2e 2e 00 00 1e 05 00 00 e8 03 26 01 |..............&.| 00903020 5c 78 32 66 64 65 76 69 63 65 73 5c 78 32 66 76 |\x2fdevices\x2fv| 00903030 69 72 74 75 61 6c 5c 78 32 66 74 74 79 5c 78 32 |irtual\x2ftty\x2| ------------------------------------------------------------ The buggy filesystem (10 MiB uncompressed) can be downloaded from http://sli.dy.fi/~sliedes/berserker/testcases/ext2.110.min.bz2 and the pristine filesystem from http://sli.dy.fi/~sliedes/berserker/testcases/pristine.ext2.bz2 See the dmesg output below. Sami ------------------------------------------------------------ INFO: task rm:1549 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. rm D ffff880006f0cd40 0 1549 1548 0x00020004 ffff88000560ddc8 0000000000000046 ffff8800068b2040 ffff88000560dfd8 ffff88000560dfd8 ffff88000560dfd8 ffff880007852040 ffff8800068b2040 ffff88000560de08 ffff880006f0cd00 ffff8800068b2040 0000000000000246 Call Trace: [<ffffffff8171d609>] schedule+0x39/0x50 [<ffffffff8171baa0>] mutex_lock_nested+0x130/0x2f0 [<ffffffff810fb467>] ? vfs_rmdir+0x67/0x120 [<ffffffff810fb467>] vfs_rmdir+0x67/0x120 [<ffffffff810fb62b>] do_rmdir+0x10b/0x120 [<ffffffff81556e5d>] ? trace_hardirqs_off_thunk+0x3a/0x3c [<ffffffff810fb94d>] sys_unlinkat+0x2d/0x40 [<ffffffff817204b1>] sysenter_dispatch+0x7/0x2a [<ffffffff81556e1e>] ? trace_hardirqs_on_thunk+0x3a/0x3f 2 locks held by rm/1549: #0: (&type->i_mutex_dir_key#4/1){+.+.+.}, at: [<ffffffff810fb58c>] do_rmdir+0x6c/0x120 #1: (&type->i_mutex_dir_key#4){+.+.+.}, at: [<ffffffff810fb467>] vfs_rmdir+0x67/0x120 Kernel panic - not syncing: hung_task: blocked tasks Pid: 361, comm: khungtaskd Not tainted 3.3.4 #3 Call Trace: [<ffffffff81713aff>] panic+0xb5/0x1be [<ffffffff8108a017>] watchdog+0x2b7/0x2c0 [<ffffffff81089dc6>] ? watchdog+0x66/0x2c0 [<ffffffff81089d60>] ? hung_task_panic+0x20/0x20 [<ffffffff810525cd>] kthread+0x8d/0xa0 [<ffffffff81720304>] kernel_thread_helper+0x4/0x10 [<ffffffff8171ec30>] ? retint_restore_args+0x13/0x13 [<ffffffff81052540>] ? kthread_flush_work_fn+0x10/0x10 [<ffffffff81720300>] ? gs_change+0x13/0x13 Rebooting in 1 seconds.. ------------------------------------------------------------
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