INFO: task syz.0.923:9343 blocked for more than 144 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.923       state:D stack:26376 pid:9343  tgid:9341  ppid:5619   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x1259/0x6920 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 schedule+0xdd/0x2c0 kernel/sched/core.c:7376
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7433
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0xccb/0x1bd0 kernel/locking/mutex.c:821
 write_versions+0x9d/0xba0 fs/nfsd/nfsctl.c:708
 nfsctl_transaction_write+0x106/0x1a0 fs/nfsd/nfsctl.c:114
 vfs_write+0x2aa/0x1050 fs/read_write.c:685
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa44399e1d9
RSP: 002b:00007fa4447fb028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa443c26090 RCX: 00007fa44399e1d9
RDX: 0000000000000003 RSI: 00002000000004c0 RDI: 0000000000000006
RBP: 00007fa443a35888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa443c26128 R14: 00007fa443c26090 R15: 00007ffd77873ce8
 </TASK>

Showing all locks held in the system:
locks held by khungtaskd/32: 1, last CPU#0:
 #0: ffffffff8fdec5a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff8fdec5a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8fdec5a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6871
locks held by kworker/1:2/1556: 7, on CPU#1:
 #0: ffff8880246f8d40 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
 #1: ffffc900061a7d08 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
 #2: ffff88802b28b1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #2: ffff88802b28b1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bb/0x4420 drivers/usb/core/hub.c:5917
 #3: ffff88807cb8d1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #3: ffff88807cb8d1d8 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2346
 #4: ffff88801e2c72a0 (&root->kernfs_supers_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x49/0x120 fs/kernfs/dir.c:1791
 #5: ffff88801e2c7180 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x51/0x120 fs/kernfs/dir.c:1792
 #6: ffff88801e2c7210 (&root->kernfs_iattr_rwsem){++++}-{4:4}, at: kernfs_unlink_sibling+0xa3/0x320 fs/kernfs/dir.c:441
locks held by kworker/u8:11/3340: 3, last CPU#0:
 #0: ffff88801d094140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
 #1: ffffc9000ef47d08 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
 #2: ffff88801d719258 (&devlink->lock_key#8){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x56/0xd20 drivers/net/netdevsim/dev.c:834
locks held by udevd/4974: 1, last CPU#1:
 #0: ffff88801e2c7210 (&root->kernfs_iattr_rwsem){++++}-{4:4}, at: kernfs_iop_permission+0x6e/0xc0 fs/kernfs/inode.c:286
locks held by getty/5358: 2, on CPU#1:
 #0: ffff88802b5540a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc900032432e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
locks held by syz-executor/5607: 2, on CPU#0:
 #0: ffff888050bfc0e8 (&type->s_umount_key#85){+.+.}-{4:4}, at: __super_lock fs/super.c:60 [inline]
 #0: ffff888050bfc0e8 (&type->s_umount_key#85){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
 #0: ffff888050bfc0e8 (&type->s_umount_key#85){+.+.}-{4:4}, at: deactivate_super fs/super.c:613 [inline]
 #0: ffff888050bfc0e8 (&type->s_umount_key#85){+.+.}-{4:4}, at: deactivate_super+0xe2/0x110 fs/super.c:610
 #1: ffffffff90289ca0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:582
locks held by kworker/1:4/5726: 2, last CPU#1:
 #0: ffff88803522e140 ((wq_completion)wg-crypt-wg0#4){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
 #1: ffffc90004707d08 ((work_completion)(&peer->transmit_packet_work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
locks held by syz-executor/8625: 1, last CPU#0:
 #0: ffffffff9090b238 (tomoyo_ss){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:198 [inline]
 #0: ffffffff9090b238 (tomoyo_ss){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:305 [inline]
 #0: ffffffff9090b238 (tomoyo_ss){.+.+}-{0:0}, at: tomoyo_read_lock security/tomoyo/common.h:1112 [inline]
 #0: ffffffff9090b238 (tomoyo_ss){.+.+}-{0:0}, at: tomoyo_path_perm+0x262/0x460 security/tomoyo/file.c:826
locks held by kworker/0:0H/8870: 2, last CPU#0:
 #0: ffff88801d05ad40 ((wq_completion)events_highpri){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
 #1: ffffc900048afd08 ((work_completion)(&vmidi->output_work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
locks held by syz.0.923/9342: 3, on CPU#1:
 #0: ffff888076788ef0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
 #1: ffff88803a1ae460 (sb_writers#19){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #2: ffffffff90289ca0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:867
locks held by syz.0.923/9343: 3, on CPU#0:
 #0: ffff8880353210b0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
 #1: ffff88803a1ae460 (sb_writers#19){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #2: ffffffff90289ca0 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x9d/0xba0 fs/nfsd/nfsctl.c:708
locks held by kworker/u8:13/10758: 3, last CPU#0:
 #0: ffff88801d094140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
 #1: ffffc900055a7d08 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
 #2: ffff8880b823bf60 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:685 [inline]
 #2: ffff8880b823bf60 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x88/0x140 kernel/sched/core.c:669
locks held by syz.3.1315/10987: 2, last CPU#1:
 #0: ffff88802c076460 (sb_writers#6){.+.+}-{0:0}, at: get_signal+0x1f2a/0x21e0 kernel/signal.c:3097
 #1: ffff88807dcbacc0 (&sb->s_type->i_mutex_key#16){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #1: ffff88807dcbacc0 (&sb->s_type->i_mutex_key#16){+.+.}-{4:4}, at: shmem_file_write_iter+0x86/0x140 mm/shmem.c:3433
locks held by udevd/11005: 1, last CPU#1:
 #0: ffff8880b823bf60 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:685 [inline]
 #0: ffff8880b823bf60 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x88/0x140 kernel/sched/core.c:669
locks held by syz.6.1332/11056: 1, on CPU#1:
 #0: ffff8880795355a0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
 #0: ffff8880795355a0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: sctp_getsockopt+0x2c7/0x7160 net/sctp/socket.c:8154
locks held by syz.6.1332/11058: 1, on CPU#1:
 #0: ffff8880795355a0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
 #0: ffff8880795355a0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: sctp_setsockopt+0x593/0xb370 net/sctp/socket.c:4609

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:123
 nmi_trigger_cpumask_backtrace+0x21f/0x2a0 lib/nmi_backtrace.c:66
 trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x141/0x190 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xcb1/0x1030 kernel/hung_task.c:561
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 11053 Comm: syz.6.1332 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:iterate_chain_key kernel/locking/lockdep.c:451 [inline]
RIP: 0010:__lock_acquire+0x689/0x1f40 kernel/locking/lockdep.c:5276
Code: f2 c1 c0 06 31 c7 89 f8 29 fe 01 d7 c1 c0 08 31 f0 89 c6 29 c2 44 8d 04 38 c1 c6 10 31 d6 89 f0 29 f7 44 01 c6 c1 c8 0d 31 f8 <44> 89 c7 89 c2 29 c7 01 f0 c1 c2 04 89 c0 31 fa 48 c1 e2 20 48 09
RSP: 0018:ffffc90006da7920 EFLAGS: 00000006
RAX: 000000004ea2f6fc RBX: ffff888022b5d6b0 RCX: 0000000000000000
RDX: 00000000023d587d RSI: 000000009a5ffc21 RDI: 00000000635e1201
RBP: 00000000000008dd R08: 00000000fdc05662 R09: 00000000000008dd
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888022b5cb00
R13: 0000000000000000 R14: 0000000000000005 R15: 0000000000000003
FS:  00007ff8a057e6c0(0000) GS:ffff888122946000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000006000 CR3: 0000000079e5a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 lock_acquire kernel/locking/lockdep.c:5942 [inline]
 lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:155 [inline]
 _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:181
 snd_rawmidi_kernel_write1+0x3b5/0x7c0 sound/core/rawmidi.c:1569
 snd_rawmidi_write+0x2dc/0xc60 sound/core/rawmidi.c:1632
 do_loop_readv_writev fs/read_write.c:851 [inline]
 do_loop_readv_writev fs/read_write.c:836 [inline]
 vfs_writev+0x5ed/0xdd0 fs/read_write.c:1060
 do_writev+0x28a/0x340 fs/read_write.c:1104
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff89f79e1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff8a057e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007ff89fa25fa0 RCX: 00007ff89f79e1d9
RDX: 0000000000000002 RSI: 0000200000000140 RDI: 0000000000000006
RBP: 00007ff89f835888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff89fa26038 R14: 00007ff89fa25fa0 R15: 00007fff2e0e08d8
 </TASK>