[v5.15] INFO: task hung in xfs_buf_item_unpin (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: eceeec79dbc6 Linux 5.15.210
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17a9b11c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6a0cae3abafc69
dashboard link: https://syzkaller.appspot.com/bug?extid=82158313da72d8b51efa
compiler: Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a8f82a67235a/disk-eceeec79.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f10abb6026a6/vmlinux-eceeec79.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ade6c70761ba/bzImage-eceeec79.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+821583...@syzkaller.appspotmail.com

INFO: task kworker/1:1H:150 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:1H state:D stack:26448 pid: 150 ppid: 2 flags:0x00004000
Workqueue: xfs-log/loop1 xlog_ioend_work
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093
__down_common+0x289/0x3b0 kernel/locking/semaphore.c:228
down+0x7e/0xd0 kernel/locking/semaphore.c:63
xfs_buf_lock+0x149/0x460 fs/xfs/xfs_buf.c:1080
xfs_buf_item_unpin+0x1e2/0x690 fs/xfs/xfs_buf_item.c:546
xfs_trans_committed_bulk+0x346/0x830 fs/xfs/xfs_trans.c:780
xlog_cil_committed+0x2cd/0xd70 fs/xfs/xfs_log_cil.c:631
xlog_cil_process_committed+0x14d/0x1a0 fs/xfs/xfs_log_cil.c:659
xlog_state_shutdown_callbacks+0x26a/0x360 fs/xfs/xfs_log.c:516
xlog_force_shutdown+0x1d3/0x1f0 fs/xfs/xfs_log.c:3886
xfs_do_force_shutdown+0x112/0x400 fs/xfs/xfs_fsops.c:533
xlog_ioend_work+0xbf/0x110 fs/xfs/xfs_log.c:1347
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
INFO: task syz.1.67:4594 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.67 state:D stack:26368 pid: 4594 ppid: 4187 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
xlog_wait+0x127/0x1a0 fs/xfs/xfs_log_priv.h:622
xlog_wait_on_iclog+0x2f3/0x4b0 fs/xfs/xfs_log.c:868
xfs_log_force_seq+0x1bf/0x420 fs/xfs/xfs_log.c:3450
__xfs_trans_commit+0x804/0xc60 fs/xfs/xfs_trans.c:890
xfs_sync_sb_buf+0xf9/0x190 fs/xfs/libxfs/xfs_sb.c:1095
xfs_ioc_setlabel fs/xfs/xfs_ioctl.c:1875 [inline]
xfs_file_ioctl+0x1400/0x1720 fs/xfs/xfs_ioctl.c:1964
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f228412be59
RSP: 002b:00007f2282364028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f22843a5090 RCX: 00007f228412be59
RDX: 00002000000004c0 RSI: 0000000041009432 RDI: 0000000000000004
RBP: 00007f22841c1e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f22843a5128 R14: 00007f22843a5090 R15: 00007ffd759eac38
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8c31ef20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:1/144:
#0: ffff888016dcd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc9000126fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
#2: ffffffff8d430290 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589
#3: ffffffff8c3239a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
#3: ffffffff8c3239a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845
2 locks held by kworker/1:1H/150:
#0: ffff888060a1c938 ((wq_completion)xfs-log/loop1){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc9000185fd00 ((work_completion)(&iclog->ic_end_io_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
2 locks held by getty/3944:
#0: ffff88814cda9098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc900026562e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
4 locks held by udevd/4179:
#0: ffff88805e6778b8 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0x9d/0xc50 fs/seq_file.c:182
#1: ffff88802ca7dc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x55/0x3c0 fs/kernfs/file.c:112
#2: ffff88804c54a490 (kn->active#32){++++}-{0:0}, at: kernfs_seq_start+0x75/0x3c0 fs/kernfs/file.c:113
#3: ffff8880234ef1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline]
#3: ffff8880234ef1a8 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16c/0x320 drivers/base/core.c:2408
2 locks held by syz-executor/4319:
#0: ffff888020c0d918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf1/0x780 block/bdev.c:915
#1: ffff888147bd5468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xa9/0xb50 drivers/block/loop.c:1366
4 locks held by kworker/u4:7/4382:
#0: ffff888016c79138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc9000340fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
#2: ffffffff8d43c1c8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
#3: ffffffff8c3239a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
#3: ffffffff8c3239a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3a5/0x750 kernel/rcu/tree_exp.h:845
1 lock held by syz.1.67/4594:
#0: ffff888020d4a460 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write_file+0x5c/0x200 fs/namespace.c:430
6 locks held by kworker/1:9/5253:
#0: ffff88801be5c938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc900032ffd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
#2: ffff8881483ad220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline]
#2: ffff8881483ad220 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5260 drivers/usb/core/hub.c:5827
#3: ffff88807c787220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline]
#3: ffff88807c787220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:974
#4: ffff8880234ef1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline]
#4: ffff8880234ef1a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:974
#5: ffff8880775180d0 (&d->usb_mutex){+.+.}-{3:3}, at: rtl28xxu_ctrl_msg+0x55/0x630 drivers/media/usb/dvb-usb-v2/rtl28xxu.c:24
2 locks held by kworker/1:16/5470:
#0: ffff888016c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc9000306fd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
3 locks held by kworker/1:17/5471:
#0: ffff88802b1e7d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc90003ca7d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
#2: ffffffff8d43c1c8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1530 net/ipv6/addrconf.c:4113
2 locks held by syz-executor/8850:
#0: ffffffff8d4989d0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:802
#1: ffffffff8d43c1c8 (rtnl_mutex){+.+.}-{3:3}, at: nl80211_pre_doit+0x28/0x540 net/wireless/nl80211.c:14969

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
watchdog+0xe1b/0xe60 kernel/hung_task.c:369
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4679 Comm: kworker/0:14 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events kfree_rcu_work
RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:214 [inline]
RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:135 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:197 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3700 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3756 [inline]
RIP: 0010:__lock_acquire+0x13e6/0x7b50 kernel/locking/lockdep.c:5012
Code: c3 81 e3 ff 1f 00 00 c1 e8 03 25 f8 03 00 00 48 8d b8 c0 b0 1c 90 be 08 00 00 00 e8 34 23 61 00 49 b8 00 00 00 00 00 fc ff df <48> 0f a3 1d 82 bf bf 0e 72 25 48 c7 c0 80 1f 2d 96 48 c1 e8 03 42
RSP: 0018:ffffc9000344f820 EFLAGS: 00000056
RAX: 0000000000000001 RBX: 0000000000000038 RCX: ffffffff815cf12c
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff901cb0c0
RBP: ffffc9000344fa50 R08: dffffc0000000000 R09: 1ffffffff2039618
R10: dffffc0000000000 R11: fffffbfff2039619 R12: dffd8ebcb98d2ecf
R13: ffff8880212dd940 R14: 00000000b98d2ecf R15: dffd8ebcb98d2ecf
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000562d715d8138 CR3: 0000000059304000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
_raw_spin_lock_irq+0xab/0xf0 kernel/locking/spinlock.c:170
process_one_work+0x9fd/0xff0 kernel/workqueue.c:2338
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup