[v6.1] INFO: task hung in io_wq_put_and_exit

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fb28aa725e05 Linux 6.1.180
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=153a7649580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31dfefc4a14efea3
dashboard link: https://syzkaller.appspot.com/bug?extid=3d7ce2293e62a7d0994b
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9a6fe2a54d0f/disk-fb28aa72.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/742b23a1d931/vmlinux-fb28aa72.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b3f257c16d2e/bzImage-fb28aa72.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3d7ce2...@syzkaller.appspotmail.com

INFO: task syz.2.18:4461 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.18 state:D stack:26512 pid:4461 ppid:4283 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2144
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x2c2/0x590 kernel/sched/completion.c:138
io_wq_exit_workers io_uring/io-wq.c:1287 [inline]
io_wq_put_and_exit+0x59d/0xb80 io_uring/io-wq.c:1322
io_uring_clean_tctx+0x12b/0x19e io_uring/tctx.c:204
io_uring_cancel_generic+0x59d/0x63c io_uring/io_uring.c:3168
io_uring_files_cancel include/linux/io_uring.h:54 [inline]
do_exit+0x5ba/0x2570 kernel/exit.c:833
do_group_exit+0x229/0x2e0 kernel/exit.c:1030
get_signal+0x1259/0x1340 kernel/signal.c:2880
arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4ce079e019
RSP: 002b:00007f4ce15d90e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f4ce0a25fa8 RCX: 00007f4ce079e019
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f4ce0a25fa8
RBP: 00007f4ce0a25fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4ce0a26038 R14: 00007fff8222efb0 R15: 00007fff8222f098
</TASK>
INFO: task iou-wrk-4461:4462 blocked for more than 145 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:iou-wrk-4461 state:D stack:25616 pid:4462 ppid:4283 flags:0x00024004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
do_uevent+0x1e9/0x490 fs/dlm/lockspace.c:210
new_lockspace fs/dlm/lockspace.c:659 [inline]
__dlm_new_lockspace+0x1d6a/0x22b0 fs/dlm/lockspace.c:719
device_create_lockspace+0xc4/0x350 fs/dlm/user.c:426
device_write+0x893/0xea0 fs/dlm/user.c:618
loop_rw_iter+0x338/0x580 include/linux/uio.h:-1
io_write+0x119c/0x17a0 io_uring/rw.c:939
io_issue_sqe+0x28b/0xc90 io_uring/io_uring.c:1747
io_wq_submit_work+0x40e/0x9c0 io_uring/io_uring.c:1828
io_worker_handle_work+0x864/0x1190 io_uring/io-wq.c:600
io_wqe_worker+0x3df/0xed0 io_uring/io-wq.c:645
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2e4f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2ed10 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527
2 locks held by kworker/0:2/1172:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc9000515fd00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
2 locks held by getty/4028:
#0: ffff88814dd4a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
3 locks held by kworker/1:4/4317:
#0: ffff88802e981538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90004137d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1500 net/ipv6/addrconf.c:4138
3 locks held by kworker/0:7/4362:
#0: ffff88802e981538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90004207d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1500 net/ipv6/addrconf.c:4138
2 locks held by kworker/1:13/4435:
#0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc9000480fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
1 lock held by iou-wrk-4461/4462:
#0: ffffffff96d4d888 (&ls_lock){+.+.}-{3:3}, at: __dlm_new_lockspace+0xad/0x22b0 fs/dlm/lockspace.c:713
1 lock held by dlm_recoverd/4467:
#0: ffff88807ab9cca0 (&ls->ls_in_recovery){+.+.}-{3:3}, at: dlm_recoverd+0xa6/0x1df0 fs/dlm/recoverd.c:312
3 locks held by kworker/1:17/4546:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc9000529fd00 (key_gc_work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
#2: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
4 locks held by kworker/u4:12/4968:
#0: ffff88801761e938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90003747d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd4ead0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:594
#3: ffff888035e453e8 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_destruct+0x112/0x300 drivers/net/wireguard/device.c:249
3 locks held by syz-executor/5189:
#0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
#0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6163
#1: ffff8880541d53e8 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_open+0x223/0x420 drivers/net/wireguard/device.c:49
#2: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
#2: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
2 locks held by cmp/5591:

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xf0e/0xf50 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5581 Comm: dhcpcd-run-hook Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:page_remove_rmap+0x9f/0xef0 mm/rmap.c:1428
Code: 83 c4 18 4c 89 e0 48 c1 e8 03 42 80 3c 30 00 74 08 4c 89 e7 e8 d2 0a 0e 00 4d 8b 34 24 44 89 f6 83 e6 01 31 ff e8 e1 e1 bc ff <41> f6 c6 01 48 89 2c 24 0f 85 48 01 00 00 45 84 ed 0f 84 1e 03 00
RSP: 0018:ffffc90003dd7780 EFLAGS: 00000293
RAX: ffffffff81c5501f RBX: ffffea00003e3580 RCX: ffff88802b9f3c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff8880783d7870 R08: ffff888140058943 R09: 1ffff1102800b128
R10: dffffc0000000000 R11: ffffed102800b129 R12: ffffea00003e3598
R13: 0000000000000000 R14: ffff8880267704d8 R15: 1ffffd400007c6b1
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c0bdfc2138 CR3: 0000000054d27000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
zap_pte_range mm/memory.c:1451 [inline]
zap_pmd_range mm/memory.c:1572 [inline]
zap_pud_range mm/memory.c:1601 [inline]
zap_p4d_range mm/memory.c:1622 [inline]
unmap_page_range+0x10db/0x25b0 mm/memory.c:1643
unmap_vmas+0x260/0x390 mm/memory.c:1728
exit_mmap+0x20d/0x970 mm/mmap.c:3250
__mmput+0x118/0x3a0 kernel/fork.c:1206
exit_mm+0x24d/0x350 kernel/exit.c:572
do_exit+0x958/0x2570 kernel/exit.c:874
do_group_exit+0x229/0x2e0 kernel/exit.c:1030
__do_sys_exit_group kernel/exit.c:1041 [inline]
__se_sys_exit_group kernel/exit.c:1039 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1039
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f28f88766c5
Code: Unable to access opcode bytes at 0x7f28f887669b.
RSP: 002b:00007fff8a624e18 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 000055c0bdfac910 RCX: 00007f28f88766c5
RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000000
RBP: 00007fff8a625148 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff8a625140
R13: 00007fff8a625150 R14: 00007f28f8a7e000 R15: 000055c0b0bbcd98
</TASK>


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