Hi,
Executing fstests' recoveryloop test group on XFS on a next-20240102 kernel
sometimes causes the following hung task report to be printed on the console,
[ 190.284008] XFS (loop5): Mounting V5 Filesystem 43ed2bb9-5b51-4bdc-af8d-af2ca7001f3f
[ 190.291326] XFS (loop5): Ending clean mount
[ 190.301165] XFS (loop5): User initiated shutdown received.
[ 190.302808] XFS (loop5): Log I/O Error (0x6) detected at xfs_fs_goingdown+0x93/0xd0 [xfs] (fs/xfs/xfs_fsops.c:458). Shutting down filesystem.
[ 190.308555] XFS (loop5): Please unmount the filesystem and rectify the problem(s)
[ 190.369214] XFS (loop5): Unmounting Filesystem 43ed2bb9-5b51-4bdc-af8d-af2ca7001f3f
[ 190.404932] XFS (loop5): Mounting V5 Filesystem 43ed2bb9-5b51-4bdc-af8d-af2ca7001f3f
[ 190.419673] XFS (loop5): Ending clean mount
[ 190.429301] XFS (loop5): User initiated shutdown received.
[ 190.431178] XFS (loop5): Log I/O Error (0x6) detected at xfs_fs_goingdown+0x93/0xd0 [xfs] (fs/xfs/xfs_fsops.c:458). Shutting down filesystem.
[ 190.437622] XFS (loop5): Please unmount the filesystem and rectify the problem(s)
[ 369.717531] INFO: task fsstress:18269 blocked for more than 122 seconds.
[ 369.724323] Not tainted 6.7.0-rc8-next-20240102+ #1
[ 369.727077] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 369.730717] task:fsstress state:D stack:0 pid:18269 tgid:18269 ppid:1 flags:0x00004006
[ 369.734945] Call Trace:
[ 369.736468] <TASK>
[ 369.737768] __schedule+0x237/0x720
[ 369.739593] schedule+0x30/0xd0
[ 369.741310] schedule_preempt_disabled+0x15/0x30
[ 369.743555] rwsem_down_read_slowpath+0x240/0x4d0
[ 369.745634] ? xlog_cil_force_seq+0x200/0x270 [xfs]
[ 369.747859] down_read+0x49/0xa0
[ 369.749436] super_lock+0xf1/0x120
[ 369.751008] ? srso_alias_return_thunk+0x5/0xfbef5
[ 369.753530] ? srso_alias_return_thunk+0x5/0xfbef5
[ 369.755865] ? xfs_log_force+0x20c/0x230 [xfs]
[ 369.758147] ? srso_alias_return_thunk+0x5/0xfbef5
[ 369.760391] ? __pfx_sync_fs_one_sb+0x10/0x10
[ 369.762516] iterate_supers+0x5a/0xe0
[ 369.764403] ksys_sync+0x64/0xb0
[ 369.766104] __do_sys_sync+0xe/0x20
[ 369.767856] do_syscall_64+0x6c/0x170
[ 369.769684] entry_SYSCALL_64_after_hwframe+0x6c/0x74
[ 369.771975] RIP: 0033:0x7f2b24e3ed5b
[ 369.773732] RSP: 002b:00007fff7183b058 EFLAGS: 00000202 ORIG_RAX: 00000000000000a2
[ 369.777022] RAX: ffffffffffffffda RBX: 000000000007a120 RCX: 00007f2b24e3ed5b
[ 369.780177] RDX: 0000000000000000 RSI: 00000000796b9c69 RDI: 0000000000000000
[ 369.783356] RBP: 028f5c28f5c28f5c R08: 0000000000000008 R09: 0000000000001010
[ 369.787096] R10: 00007f2b24e15228 R11: 0000000000000202 R12: 0000000000000000
[ 369.790256] R13: 8f5c28f5c28f5c29 R14: 00000000004034c0 R15: 00007f2b250156c0
[ 369.793499] </TASK>
The sb->s_umount semaphore was owned by a task executing systemd-coredump. The
systemd-coredump task was busy executing shrink_dcache_parent() as shown below,
systemd-coredum 18274 [001] 85214.162988: probe:d_walk: (ffffffff88218580) parent_path="/" fs_type="tmpfs"
ffffffff88218581 d_walk+0x1 ([kernel.kallsyms])
ffffffff8821a8e2 shrink_dcache_parent+0x52 ([kernel.kallsyms])
ffffffff8821ac9b shrink_dcache_for_umount+0x3b ([kernel.kallsyms])
ffffffff881f9c10 generic_shutdown_super+0x20 ([kernel.kallsyms])
ffffffff881fa667 kill_litter_super+0x27 ([kernel.kallsyms])
ffffffff881fb3b5 deactivate_locked_super+0x35 ([kernel.kallsyms])
ffffffff88226d30 cleanup_mnt+0x100 ([kernel.kallsyms])
ffffffff87eef72c task_work_run+0x5c ([kernel.kallsyms])
ffffffff87ec9763 do_exit+0x2b3 ([kernel.kallsyms])
ffffffff87ec9b90 do_group_exit+0x30 ([kernel.kallsyms])
ffffffff87ec9c38 [unknown] ([kernel.kallsyms])
ffffffff88b9930c do_syscall_64+0x6c ([kernel.kallsyms])
ffffffff88c000e5 entry_SYSCALL_64+0xa5 ([kernel.kallsyms])
Trying to obtain more debug data via perf caused the 'perf record' task to
indefinitely enter into the TASK_UNINTERRUPTIBLE state. I will try to recreate
the bug and debug it further.
The following is the fstests configuration that was used.
FSTYP=xfs
TEST_DEV=/dev/loop7
TEST_DIR=/media/test
SCRATCH_DEV=/dev/loop5
SCRATCH_MNT=/media/scratch
MKFS_OPTIONS='-f -m reflink=1,rmapbt=1, -i sparse=1,'
MOUNT_OPTIONS='-o usrquota,grpquota,prjquota'
LOGWRITES_DEV=/dev/loop6
SOAK_DURATION=9900
The recoveryloop group of tests can then be executed by,
$ ./check -g recoveryloop
--
Chandan
