INFO: task syz.3.2347:14035 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.2347      state:D stack:28456 pid:14035 tgid:14032 ppid:5617   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5520 [inline]
 __schedule+0x17d4/0x5820 kernel/sched/core.c:7270
 __schedule_loop kernel/sched/core.c:7347 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7362
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7419
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
 write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:708
 nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:114
 vfs_write+0x296/0xba0 fs/read_write.c:685
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f289299e0d9
RSP: 002b:00007f2893819028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f2892c25fa0 RCX: 00007f289299e0d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f2892a35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2892c26038 R14: 00007f2892c25fa0 R15: 00007fff278787f8
 </TASK>
INFO: task syz.3.2347:14036 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.3.2347      state:D stack:28552 pid:14036 tgid:14032 ppid:5617   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5520 [inline]
 __schedule+0x17d4/0x5820 kernel/sched/core.c:7270
 __schedule_loop kernel/sched/core.c:7347 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7362
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7419
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
 write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:867
 nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:114
 vfs_write+0x296/0xba0 fs/read_write.c:685
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f289299e0d9
RSP: 002b:00007f28937f8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f2892c26090 RCX: 00007f289299e0d9
RDX: 0000000000000001 RSI: 0000200000000240 RDI: 0000000000000004
RBP: 00007f2892a35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2892c26128 R14: 00007f2892c26090 R15: 00007fff278787f8
 </TASK>

Showing all locks held in the system:
locks held by pool_workqueue_/3: 1, on CPU#1:
 #0: ffffffff8ed607e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
 #0: ffffffff8ed607e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:966
locks held by khungtaskd/30: 1, last CPU#1:
 #0: ffffffff8ed5a420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff8ed5a420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8ed5a420 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6793
locks held by udevd/4973: 1, last CPU#0:
 #0: ffff88807fe72460 (sb_writers#7){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:494
locks held by getty/5363: 2, on CPU#1:
 #0: ffff8880358bd0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by udevd/5728: 2, last CPU#0:
 #0: ffff8880b863bb20 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xb2/0x160 kernel/sched/core.c:685
 #1: ffff8880b8624408 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x57/0x7d0 kernel/sched/psi.c:933
locks held by kworker/0:5/5756: 6, on CPU#0:
 #0: ffff88802229f140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88802229f140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88802229f140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3352 [inline]
 #0: ffff88802229f140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3470
 #1: ffffc90004837c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90004837c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90004837c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3352 [inline]
 #1: ffffc90004837c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3470
 #2: ffff888029ae01d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #2: ffff888029ae01d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5907
 #3: ffff888029b2a568 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3260 [inline]
 #3: ffff888029b2a568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5472 [inline]
 #3: ffff888029b2a568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5715 [inline]
 #3: ffff888029b2a568 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5879 [inline]
 #3: ffff888029b2a568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x20a1/0x4d30 drivers/usb/core/hub.c:5961
 #4: ffff8880298c7d60 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5473 [inline]
 #4: ffff8880298c7d60 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5715 [inline]
 #4: ffff8880298c7d60 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5879 [inline]
 #4: ffff8880298c7d60 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x20c9/0x4d30 drivers/usb/core/hub.c:5961
 #5: ffff8880b863bb20 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xb2/0x160 kernel/sched/core.c:685
locks held by syz-executor/13805: 1, on CPU#1:
 #0: ffffffff8ed607e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
 #0: ffffffff8ed607e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:966
locks held by syz.4.2316/13894: 3, on CPU#0:
 #0: ffff8880747240f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
 #1: ffff88803556c460 (sb_writers#22){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2754 [inline]
 #1: ffff88803556c460 (sb_writers#22){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
 #2: ffffffff8f0997a0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:867
locks held by syz.3.2347/14035: 3, on CPU#0:
 #0: ffff88807dcae9b0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
 #1: 
ffff88802ae1c460 (sb_writers#22){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2754 [inline]
ffff88802ae1c460 (sb_writers#22){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
 #2: ffffffff8f0997a0 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:708
locks held by syz.3.2347/14036: 3, on CPU#0:
 #0: ffff88801ffea470 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
 #1: ffff88802ae1c460 (sb_writers#22){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2754 [inline]
 #1: ffff88802ae1c460 (sb_writers#22){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
 #2: ffffffff8f0997a0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:867
locks held by dhcpcd/14108: 1, on CPU#0:
 #0: ffff888067e90800 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1025 [inline]
 #0: ffff888067e90800 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x7a/0x1f0 net/socket.c:734
locks held by sed/15798: 1, last CPU#0:
 #0: ffffffff8eea9090 (remove_cache_srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:198 [inline]
 #0: ffffffff8eea9090 (remove_cache_srcu){.+.+}-{0:0}, at: srcu_read_lock+0x27/0x60 include/linux/srcu.h:305

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
 nmi_trigger_cpumask_backtrace+0x17d/0x390 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+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd7/0x1030 kernel/hung_task.c:561
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 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: 14494 Comm: kworker/u8:3 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x80 kernel/kcov.c:206
Code: 89 fb e8 23 00 00 00 48 8b 3d 04 c2 ac 0c 48 89 de 5b e9 f3 25 64 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 48 8b 04 24 65 48 8b 0d 98 b1 cb 11 65 48 8b 15 98 b1
RSP: 0018:ffffc900034e79d0 EFLAGS: 00000246
RAX: ffffffff8517fd16 RBX: ffff88802b308020 RCX: ffff888067b13e80
RDX: 0000000000000000 RSI: 0000000045ea8147 RDI: 0000000033c60102
RBP: 0000000000000012 R08: ffff888067b13e80 R09: 0000000000000003
R10: 000000000000002e R11: 0000000000000000 R12: ffff88802b30801c
R13: 0000000000000000 R14: ffff88802b308020 R15: 0000000045ea8147
FS:  0000000000000000(0000) GS:ffff888124cf1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f198780e7d0 CR3: 000000000eb46000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 do_csum lib/checksum.c:70 [inline]
 ip_fast_csum+0x17d/0x2b0 lib/checksum.c:99
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:767 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:801 [inline]
 nsim_dev_trap_report_work+0x58e/0xb40 drivers/net/netdevsim/dev.c:847
 process_one_work kernel/workqueue.c:3387 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>