INFO: task syz-executor:8000 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:23816 pid:8000 tgid:8000 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0xfe6/0x5fa0 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:6964
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7021
__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:575
nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1353
deactivate_locked_super+0xc1/0x1b0 fs/super.c:474
deactivate_super fs/super.c:507 [inline]
deactivate_super+0xe7/0x110 fs/super.c:503
cleanup_mnt+0x21f/0x450 fs/namespace.c:1318
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:44 [inline]
exit_to_user_mode_loop+0x100/0x4b0 kernel/entry/common.c:75
__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_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x4ea/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1a7479c1d7
RSP: 002b:00007ffd98a99ad8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f1a74830b3b RCX: 00007f1a7479c1d7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd98a99b90
RBP: 00007ffd98a99b90 R08: 00007ffd98a9ab90 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd98a9ac20
R13: 00007f1a74830b3b R14: 0000000000047570 R15: 00007ffd98a9ac60
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e5e3120 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e5e3120 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e5e3120 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by syz-executor/5831:
#0: ffff8880796800e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff8880796800e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff8880796800e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff8880796800e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:503
#1: ffffffff8ea476a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
2 locks held by syz-executor/5838:
#0: ffff88804d3820e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff88804d3820e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff88804d3820e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff88804d3820e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:503
#1: ffffffff8ea476a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
2 locks held by syz-executor/5840:
#0: ffff888025c280e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff888025c280e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff888025c280e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff888025c280e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:503
#1: ffffffff8ea476a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
4 locks held by kworker/1:3/5874:
3 locks held by kworker/1:5/5911:
#0: ffff88813fe15948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232
#1: ffffc90004d3fc98 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233
#2: ffffffff8e5ef8f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x27f/0x3c0 kernel/rcu/tree_exp.h:311
2 locks held by syz.1.364/7709:
#0: ffffffff904a2bd0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8ea476a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1596
2 locks held by syz-executor/8000:
#0: ffff88802adc40e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff88802adc40e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff88802adc40e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff88802adc40e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:503
#1: ffffffff8ea476a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
2 locks held by getty/9373:
#0: ffff888035efa0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900045c32f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211
5 locks held by syz-executor/11851:
#0: ffff88807f634ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:499
#1: ffff88807f6340c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x35c/0x1240 net/bluetooth/hci_sync.c:5315
#2: ffffffff9068ee28 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2143 [inline]
#2: ffffffff9068ee28 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x280 net/bluetooth/hci_conn.c:2637
#3: ffff888059ec4338 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x80/0x760 net/bluetooth/l2cap_core.c:1763
#4: ffffffff8e5ef8f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
1 lock held by syz.5.1293/12060:
=============================================
NMI backtrace for cpu 1
CPU: 1 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 01/24/2026
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+0xcc3/0xfe0 kernel/hung_task.c:515
kthread+0x3b3/0x730 kernel/kthread.c:463
ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 1 Comm: init Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:hlock_class kernel/locking/lockdep.c:229 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3820 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3876 [inline]
RIP: 0010:__lock_acquire+0x830/0x2630 kernel/locking/lockdep.c:5237
Code: 84 86 fc ff ff ba 06 00 00 00 48 89 de 48 89 ef e8 75 eb ff ff 8b 4c 24 08 85 c0 0f 85 6a fc ff ff e9 5d fb ff ff 0f b7 43 20 <66> 25 ff 1f 0f b7 c0 48 0f a3 05 21 4e 08 14 0f 83 b2 09 00 00 49
RSP: 0018:ffffc90000067550 EFLAGS: 00000046
RAX: 0000000000000253 RBX: ffff888141290b58 RCX: 0000000000000001
RDX: 0000000077bf8efe RSI: 00000000df02d2ad RDI: 0000000063bd09ee
RBP: ffff888141290000 R08: 0000000084ba3741 R09: 0000000000000253
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000253 R14: 0000000000000001 R15: 74971d9c77bf8efe
FS: 00007fe827772c80(0000) GS:ffff8881245e2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b315e3ff8 CR3: 0000000031b86000 CR4: 00000000003526f0
Call Trace:
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x17c/0x330 kernel/locking/lockdep.c:5825
_raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378
__dentry_kill+0x2ab/0x600 fs/dcache.c:683
shrink_kill fs/dcache.c:1147 [inline]
shrink_dentry_list+0x180/0x5e0 fs/dcache.c:1174
shrink_dcache_tree+0x100/0x570 fs/dcache.c:1620
shrink_dcache_parent fs/dcache.c:1626 [inline]
d_invalidate fs/dcache.c:1708 [inline]
d_invalidate+0x13a/0x290 fs/dcache.c:1693
proc_invalidate_siblings_dcache+0x44f/0x750 fs/proc/inode.c:142
release_task+0xd41/0x1ab0 kernel/exit.c:291
wait_task_zombie kernel/exit.c:1274 [inline]
wait_consider_task+0x1791/0x3e00 kernel/exit.c:1501
do_wait_thread kernel/exit.c:1564 [inline]
__do_wait+0x218/0x8b0 kernel/exit.c:1682
do_wait+0x1ec/0x540 kernel/exit.c:1716
kernel_wait4+0x16d/0x280 kernel/exit.c:1875
__do_sys_wait4+0x161/0x170 kernel/exit.c:1903
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe8278c2407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffc44c73d20 EFLAGS: 00000202 ORIG_RAX: 000000000000003d
RAX: ffffffffffffffda RBX: 00007fe827772c80 RCX: 00007fe8278c2407
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffffffffffffffff
RBP: 00007fe827ac1e89 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007fe827adc490
R13: 00007ffc44c73d7c R14: 00007fe827b1c000 R15: 0000557e252e9d98