INFO: task syz.7.2730:19541 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.7.2730 state:D stack:27080 pid:19541 tgid:19539 ppid:18409 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0xfee/0x6120 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7008
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1364
deactivate_locked_super+0xc1/0x1b0 fs/super.c:476
deactivate_super fs/super.c:509 [inline]
deactivate_super+0xe7/0x110 fs/super.c:505
cleanup_mnt+0x21f/0x450 fs/namespace.c:1312
task_work_run+0x150/0x240 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0x100/0x4a0 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
do_syscall_64+0x668/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb26b79c799
RSP: 002b:00007fb2699d5028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffec RBX: 00007fb26ba16090 RCX: 00007fb26b79c799
RDX: 0000200000000300 RSI: 0000200000000040 RDI: 0000000000000000
RBP: 00007fb26b832c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb26ba16128 R14: 00007fb26ba16090 R15: 00007ffd8dbc3798
Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8e7e7660 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e7e7660 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e7e7660 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
6 locks held by kworker/u10:10/11602:
3 locks held by kworker/u10:23/12142:
#0: ffff888033759948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
#1: ffffc9000577fd08 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
#2: ffffffff906145e8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff906145e8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x11f/0x1360 net/ipv6/addrconf.c:4198
1 lock held by syz.0.2461/17776:
3 locks held by kworker/0:10/17813:
#0: ffff88813fe63148 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
#1: ffffc900042d7d08 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
#2: ffff888033682240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x1b8/0x63b0 drivers/net/netdevsim/fib.c:1490
2 locks held by syz.4.2525/18235:
#0: ffffffff906c0910 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8ec583a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1a80 fs/nfsd/nfsctl.c:1903
2 locks held by syz.7.2730/19541:
#0: ffff888038fb80e0 (&type->s_umount_key#56){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff888038fb80e0 (&type->s_umount_key#56){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff888038fb80e0 (&type->s_umount_key#56){++++}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff888038fb80e0 (&type->s_umount_key#56){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec583a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by getty/20087:
#0: ffff8880384cb0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900032042f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211
2 locks held by syz.6.3041/21060:
#0: ffff88807e8cc0e0 (&type->s_umount_key#56){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88807e8cc0e0 (&type->s_umount_key#56){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88807e8cc0e0 (&type->s_umount_key#56){++++}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88807e8cc0e0 (&type->s_umount_key#56){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec583a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz.5.3043/21063:
#0: ffff888022fbe0e0 (&type->s_umount_key#56){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff888022fbe0e0 (&type->s_umount_key#56){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff888022fbe0e0 (&type->s_umount_key#56){++++}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff888022fbe0e0 (&type->s_umount_key#56){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec583a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
3 locks held by syz-executor/21170:
#0: ffffffff906145e8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff906145e8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff906145e8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8bb/0x2380 net/core/rtnetlink.c:4071
#1: ffff888047b01528 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_open+0x1fa/0x4d0 drivers/net/wireguard/device.c:50
#2: ffffffff8e7f3278 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x27f/0x3c0 kernel/rcu/tree_exp.h:311
4 locks held by syz.3.3071/21232:
4 locks held by syz.3.3071/21235:
#0: ffff88804c7e10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffff88804c7e1130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: tty_write_lock drivers/tty/tty_io.c:939 [inline]
#1: ffff88804c7e1130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: iterate_tty_write drivers/tty/tty_io.c:958 [inline]
#1: ffff88804c7e1130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: file_tty_write.isra.0+0x24b/0x890 drivers/tty/tty_io.c:1081
#2: ffff88804c7e12e8 (&tty->termios_rwsem){++++}-{4:4}, at: class_rwsem_read_constructor include/linux/rwsem.h:259 [inline]
#2: ffff88804c7e12e8 (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_write+0x1c4/0x12d0 drivers/tty/n_tty.c:2349
#3: ffffc90004fbb380 (&ldata->output_lock){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#3: ffffc90004fbb380 (&ldata->output_lock){+.+.}-{4:4}, at: process_output_block drivers/tty/n_tty.c:513 [inline]
#3: ffffc90004fbb380 (&ldata->output_lock){+.+.}-{4:4}, at: n_tty_write+0x5c5/0x12d0 drivers/tty/n_tty.c:2366
1 lock held by syz.8.3073/21252:
#0: ffffffff8f4ef8e8 (tty_mutex){+.+.}-{4:4}, at: tty_open_by_driver drivers/tty/tty_io.c:2037 [inline]
#0: ffffffff8f4ef8e8 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x539/0xfa0 drivers/tty/tty_io.c:2120
1 lock held by syz.2.3063/21320:
1 lock held by sed/21325:
=============================================
NMI backtrace for cpu 0
CPU: 0 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 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:436
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245