INFO: task syz.4.992:11035 blocked for more than 144 seconds.
Tainted: G U L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.992 state:D stack:27464 pid:11035 tgid:11026 ppid:8682 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0xfee/0x60e0 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7004
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7061
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
nfsd_nl_threads_set_doit+0x718/0xc60 fs/nfsd/nfsctl.c:1597
genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa54/0xc30 net/socket.c:2592
___sys_sendmsg+0x190/0x1e0 net/socket.c:2646
__sys_sendmsg+0x170/0x220 net/socket.c:2678
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f994899c629
RSP: 002b:00007f994978b028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f9948c16360 RCX: 00007f994899c629
RDX: 0000000000040010 RSI: 0000200000000180 RDI: 0000000000000005
RBP: 00007f9948a32b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9948c163f8 R14: 00007f9948c16360 R15: 00007ffd4a99f578
Showing all locks held in the system:
2 locks held by kworker/0:1/10:
#0: ffff88813fe63548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1287/0x1920 kernel/workqueue.c:3250
#1: ffff8880b8424648 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:225 [inline]
#1: ffff8880b8424648 (psi_seq){-.-.}-{0:0}, at: __schedule+0x2c11/0x60e0 kernel/sched/core.c:6901
1 lock held by khungtaskd/31:
#0: ffffffff8e7e9220 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e7e9220 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e7e9220 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by getty/6550:
#0: ffff88803502d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc90004b7b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211
2 locks held by syz.0.926/10689:
#0: ffffffff906bd8f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8ec58488 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1b20 fs/nfsd/nfsctl.c:1893
2 locks held by syz.4.992/11035:
#0: ffffffff906bd8f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8ec58488 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x718/0xc60 fs/nfsd/nfsctl.c:1597
2 locks held by syz-executor/11241:
#0: ffff8880376b40e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880376b40e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff8880376b40e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff8880376b40e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec58488 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
2 locks held by syz.1.1269/12353:
#0: ffff88802a3360e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88802a3360e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88802a3360e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88802a3360e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec58488 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
3 locks held by syz-executor/12518:
#0: ffff888054274ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:500
#1: ffff8880542740c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x35c/0x1240 net/bluetooth/hci_sync.c:5346
#2: ffffffff8e7f4e38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
2 locks held by syz-executor/12607:
#0: ffff88805ccba0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88805ccba0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88805ccba0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88805ccba0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec58488 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
2 locks held by syz.5.1328/12667:
#0: ffffffff906bd8f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8ec58488 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1b20 fs/nfsd/nfsctl.c:1893
1 lock held by syz.9.1432/13213:
#0: ffffffff8e7f4e38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
1 lock held by syz.3.1479/13440:
2 locks held by syz.3.1503/13534:
#0: ffffffff905f8eb0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:577
#1: ffffffff906117a8 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline]
#1: ffffffff906117a8 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x7ec/0xab0 net/core/net_namespace.c:248
1 lock held by dhcpcd/13540:
#0: ffff88808e4d8260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1709 [inline]
#0: ffff88808e4d8260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf50 net/packet/af_packet.c:3198
1 lock held by dhcpcd/13541:
#0: ffff88802943a260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1709 [inline]
#0: ffff88802943a260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf50 net/packet/af_packet.c:3198
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U L syzkaller #0 PREEMPT(full)
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
__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:113
nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [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:346 [inline]
watchdog+0xd25/0x1050 kernel/hung_task.c:515
kthread+0x370/0x450 kernel/kthread.c:467
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245