INFO: task syz-executor:10258 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-executor state:D stack:24200 pid:10258 tgid:10258 ppid:1 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: 0033:0x7fbf3a19da57
RSP: 002b:00007ffeb0d0ff38 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fbf3a232048 RCX: 00007fbf3a19da57
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffeb0d0fff0
RBP: 00007ffeb0d0fff0 R08: 00007ffeb0d10ff0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffeb0d11080
R13: 00007fbf3a232048 R14: 000000000007148a R15: 00007ffeb0d110c0
INFO: task syz.6.1345:12725 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.6.1345 state:D stack:26792 pid:12725 tgid:12719 ppid:10511 task_flags:0x400140 flags:0x00080006
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
vfs_get_super fs/super.c:1338 [inline]
get_tree_keyed+0x18a/0x1d0 fs/super.c:1364
vfs_get_tree+0x92/0x320 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3763 [inline]
do_new_mount fs/namespace.c:3839 [inline]
path_mount+0x7d0/0x23d0 fs/namespace.c:4159
do_mount fs/namespace.c:4172 [inline]
__do_sys_mount fs/namespace.c:4361 [inline]
__se_sys_mount fs/namespace.c:4338 [inline]
__x64_sys_mount+0x293/0x310 fs/namespace.c:4338
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: 0033:0x7f35d3f9c819
RSP: 002b:00007f35d4e7d028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f35d4216090 RCX: 00007f35d3f9c819
RDX: 00002000000001c0 RSI: 00002000000000c0 RDI: 0000000000000000
RBP: 00007f35d4032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f35d4216128 R14: 00007f35d4216090 R15: 00007ffc407f2738
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e7e7760 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e7e7760 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e7e7760 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by syz-executor/5822:
#0: ffff8880261e40e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880261e40e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff8880261e40e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff8880261e40e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec58e28 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/5823:
#0: ffffffff90616868 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff90616868 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x220 drivers/net/tun.c:3436
#1: ffffffff8e7f32b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
2 locks held by kworker/u8:19/9186:
#0: ffff88801f79b148 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
#1: ffffc900046c7d08 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
2 locks held by syz.0.810/9946:
#0: ffffffff906c2bb0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8ec58e28 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x6c1/0xc00 fs/nfsd/nfsctl.c:1607
2 locks held by syz-executor/10258:
#0: ffff88807a2ac0e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88807a2ac0e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88807a2ac0e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88807a2ac0e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec58e28 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by getty/11808:
#0: ffff888038c920a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900055f32f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211
2 locks held by syz.6.1345/12725:
#0: ffff88807b9cc0e0 (&type->s_umount_key#52/1){+.+.}-{4:4}, at: alloc_super+0x244/0xd20 fs/super.c:345
#1: ffffffff8ec58e28 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/12954:
#0: ffff88808080e0e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88808080e0e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88808080e0e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88808080e0e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec58e28 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/13146:
#0: ffff888094b0c0e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff888094b0c0e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff888094b0c0e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff888094b0c0e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec58e28 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
3 locks held by kworker/u10:5/13945:
#0: ffff88801c6b6948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
#1: ffffc9000448fd08 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
#2: ffffffff905fe010 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xb8/0x920 net/core/net_namespace.c:675
2 locks held by syz.9.1592/13950:
#0: ffff88802d6e80e0 (&type->s_umount_key#52/1){+.+.}-{4:4}, at: alloc_super+0x244/0xd20 fs/super.c:345
#1: ffffffff8ec58e28 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
4 locks held by syz-executor/14290:
#0: ffff8880a1b64ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:500
#1: ffff8880a1b640c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x35c/0x1240 net/bluetooth/hci_sync.c:5356
#2: ffffffff908afb48 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2151 [inline]
#2: ffffffff908afb48 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x280 net/bluetooth/hci_conn.c:2650
#3: ffff888035748b00 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x95/0x710 net/bluetooth/l2cap_core.c:1777
3 locks held by syz.2.1888/15560:
#0: ffff88805cd1cec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:500
#1: ffff88805cd1c0c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x35c/0x1240 net/bluetooth/hci_sync.c:5356
#2: ffffffff8e7f32b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
3 locks held by syz.0.1892/15574:
#0: ffff88804c934ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:500
#1: ffff88804c9340c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x35c/0x1240 net/bluetooth/hci_sync.c:5356
#2: ffffffff908afb48 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2151 [inline]
#2: ffffffff908afb48 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x280 net/bluetooth/hci_conn.c:2650
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
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