INFO: task syz.3.722:11295 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.3.722       state:D stack:27016 pid:11295 tgid:11286 ppid:5620   task_flags:0x400140 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
 nfsd_nl_version_set_doit+0xc4/0x7a0 fs/nfsd/nfsctl.c:1844
 genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114
 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
 genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209
 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2575
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1338 [inline]
 netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1364
 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:800 [inline]
 __sock_sendmsg net/socket.c:815 [inline]
 ____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2713
 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2767
 __sys_sendmsg+0x160/0x210 net/socket.c:2799
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x121/0x770 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f476779e159
RSP: 002b:00007f47651b0028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f4767a26360 RCX: 00007f476779e159
RDX: 0000000020004000 RSI: 00002000000002c0 RDI: 0000000000000007
RBP: 00007f476783506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4767a263f8 R14: 00007f4767a26360 R15: 00007ffe341b4d08
 </TASK>

Showing all locks held in the system:
locks held by khungtaskd/32: 1, last CPU#1:
 #0: ffffffff8edec3a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff8edec3a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8edec3a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6871
locks held by getty/5373: 2, on CPU#0:
 #0: ffff88823bf968a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc900032262e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
locks held by syz.2.603/10387: 2, on CPU#1:
 #0: ffffffff90d87208 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff8f288ac0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x1a3/0x1dc0 fs/nfsd/nfsctl.c:2057
locks held by syz.3.722/11295: 2, on CPU#1:
 #0: ffffffff90d87208 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff8f288ac0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_version_set_doit+0xc4/0x7a0 fs/nfsd/nfsctl.c:1844
locks held by kworker/u10:2/12417: 2, on CPU#0:
 #0: ffff88801f30c940 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
 #1: ffffc900088afd08 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
locks held by kworker/u10:15/13076: 3, last CPU#0:
 #0: ffff88801c09c140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
 #1: ffffc90003a1fd08 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
 #2: ffff88807712b258 (&devlink->lock_key#3){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x56/0xd20 drivers/net/netdevsim/dev.c:834
locks held by syz.5.1050/13870: 1, on CPU#1:
 #0: ffff88807b5c0340 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
 #0: ffff88807b5c0340 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1f5/0x470 mm/util.c:579
locks held by syz.5.1050/13875: 1, on CPU#1:
 #0: ffff88807b5c0340 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
 #0: ffff88807b5c0340 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1f5/0x470 mm/util.c:579
locks held by syz.5.1050/13876: 2, on CPU#0:
 #0: ffffffff90cbefa8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
 #1: ffffffff90cd7b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:149 [inline]
 #1: ffffffff90cd7b00 (rtnl_mutex){+.+.}-{4:4}, at: register_netdev+0x18/0x50 net/core/dev.c:11660
locks held by syz.5.1050/13892: 4, last CPU#0:
 #0: ffffffff8ef3cdb0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1542 [inline]
 #0: ffffffff8ef3cdb0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm kernel/fork.c:1595 [inline]
 #0: ffffffff8ef3cdb0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_process+0x4816/0x8380 kernel/fork.c:2311
 #1: ffff88807b5c0340 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
 #1: ffff88807b5c0340 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x127/0x2370 mm/mmap.c:1716
 #2: ffff8880130c0f80 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:552 [inline]
 #2: ffff8880130c0f80 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x1c9/0x2370 mm/mmap.c:1723
 #3: ffffffff8edec3a0 (rcu_read_lock){....}-{1:3}, at: psi_sched_switch kernel/sched/stats.h:218 [inline]
 #3: ffffffff8edec3a0 (rcu_read_lock){....}-{1:3}, at: __schedule+0x2e0c/0x6920 kernel/sched/core.c:7278
locks held by syz.5.1050/13894: 1, on CPU#1:
 #0: ffff88807b5c0340 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:600 [inline]
 #0: ffff88807b5c0340 (&mm->mmap_lock){++++}-{4:4}, at: __mm_populate+0x229/0x3a0 mm/gup.c:1942
locks held by syz.5.1050/13896: 5, last CPU#0:
 #0: ffffffff90cbefa8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
 #1: ffffffff90cd7b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:149 [inline]
 #1: ffffffff90cd7b00 (rtnl_mutex){+.+.}-{4:4}, at: register_netdev+0x18/0x50 net/core/dev.c:11660
 #2: ffff8880b84402c8 ((local_lock_t *)&pcs->lock){+.+.}-{3:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #2: ffff8880b84402c8 ((local_lock_t *)&pcs->lock){+.+.}-{3:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #2: ffff8880b84402c8 ((local_lock_t *)&pcs->lock){+.+.}-{3:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
 #2: ffff8880b84402c8 ((local_lock_t *)&pcs->lock){+.+.}-{3:3}, at: unwind_next_frame+0xbd/0x2090 arch/x86/kernel/unwind_orc.c:495
 #3: ffffffff8eff4b00 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: fs_reclaim_acquire mm/page_alloc.c:4392 [inline]
 #3: ffffffff8eff4b00 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: fs_reclaim_acquire+0x70/0x100 mm/page_alloc.c:4383
 #4: ffffffff8edec3a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #4: ffffffff8edec3a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #4: ffffffff8edec3a0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
 #4: ffffffff8edec3a0 (rcu_read_lock){....}-{1:3}, at: kernfs_root+0x23/0x2a0 fs/kernfs/kernfs-internal.h:76
locks held by syz.5.1050/13924: 2, on CPU#0:
 #0: ffffffff90cbefa8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
 #1: ffffffff90cd7b00 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x21e/0x780 net/ipv4/ip_tunnel.c:1136
locks held by syz.5.1050/13926: 1, on CPU#0:
 #0: ffff88807b5c0340 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable include/linux/mmap_lock.h:609 [inline]
 #0: ffff88807b5c0340 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:450 [inline]
 #0: ffff88807b5c0340 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x160/0x6f0 mm/mmap_lock.c:501
locks held by syz.0.1052/13901: 2, on CPU#1:
 #0: ffffffff90cbefa8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
 #1: ffffffff90cd7b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
 #1: ffffffff90cd7b00 (rtnl_mutex){+.+.}-{4:4}, at: unregister_netdevice_notifier_net+0x1c/0xf0 net/core/dev.c:2157
locks held by syz.0.1052/13907: 2, on CPU#0:
 #0: ffffffff90cbefa8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
 #1: ffffffff90cd7b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
 #1: ffffffff90cd7b00 (rtnl_mutex){+.+.}-{4:4}, at: unregister_netdevice_notifier_net+0x1c/0xf0 net/core/dev.c:2157
locks held by syz.1.1054/13906: 2, on CPU#1:
 #0: ffffffff90cbefa8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
 #1: ffffffff90cd7b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
 #1: ffffffff90cd7b00 (rtnl_mutex){+.+.}-{4:4}, at: unregister_netdevice_notifier_net+0x1c/0xf0 net/core/dev.c:2157
locks held by syz.1.1054/13912: 2, on CPU#0:
 #0: ffffffff90cbefa8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
 #1: ffffffff8edf8178 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3904
locks held by syz.1.1054/13915: 3, on CPU#0:
 #0: ffffffff90cbefa8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
 #1: ffffffff90cd7b00 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0x92/0x890 net/core/dev.c:13317
 #2: ffffffff8edf82a8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x27f/0x3c0 kernel/rcu/tree_exp.h:311
locks held by syz.4.1055/13914: 2, on CPU#1:
 #0: ffffffff90cbefa8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
 #1: ffffffff8edf8178 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3904
locks held by syz.4.1055/13917: 2, on CPU#0:
 #0: ffffffff90cbefa8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
 #1: ffffffff90cd7b00 (rtnl_mutex){+.+.}-{4:4}, at: cfg80211_pernet_exit+0x17/0x130 net/wireless/core.c:1894

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

NMI backtrace for cpu 0
CPU: 0 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 07/24/2026
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 16 Comm: pr/ttyS0 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:io_serial_in+0x87/0xb0 drivers/tty/serial/8250/8250_port.c:410
Code: 9a 5b fc 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1a 66 03 5d 40 89 da ec <5b> 0f b6 c0 5d 41 5c c3 cc cc cc cc e8 88 17 ce fc eb a2 e8 11 18
RSP: 0018:ffffc90000157958 EFLAGS: 00000002
RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: ffffffff85b00bd0 RDI: ffffffff9bc654a0
RBP: ffffffff9bc65460 R08: 0000000000000001 R09: 000000000000001f
R10: 0000000000000000 R11: 205d323354202020 R12: 0000000000000000
R13: 0000000000000020 R14: fffffbfff378cae9 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888123c52000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb28a605ff8 CR3: 00000000748fa000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 serial_in drivers/tty/serial/8250/8250.h:128 [inline]
 serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
 wait_for_lsr+0x13a/0x210 drivers/tty/serial/8250/8250_port.c:2013
 serial8250_fifo_wait_for_lsr_thre+0x5f/0xd0 drivers/tty/serial/8250/8250_port.c:3270
 __serial8250_console_fifo_write+0x23c/0x290 drivers/tty/serial/8250/8250_port.c:3372
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3378 [inline]
 __serial8250_console_write drivers/tty/serial/8250/8250_port.c:3429 [inline]
 serial8250_console_write+0xf46/0x1330 drivers/tty/serial/8250/8250_port.c:3493
 nbcon_emit_next_record+0x8f7/0xa70 kernel/printk/nbcon.c:1070
 nbcon_emit_one+0x1a8/0x2b0 kernel/printk/nbcon.c:1157
 nbcon_kthread_func+0x613/0x7d0 kernel/printk/nbcon.c:1271
 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>