INFO: task syz.0.5376:25619 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.0.5376 state:D stack:26856 pid:25619 tgid:25618 ppid:16817 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0xc69/0x1ca0 kernel/locking/mutex.c:776 nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575 nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1347 deactivate_locked_super+0xc1/0x1a0 fs/super.c:474 deactivate_super fs/super.c:507 [inline] deactivate_super+0xde/0x100 fs/super.c:503 cleanup_mnt+0x225/0x450 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+0xfb/0x540 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+0x4ee/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdad898f749 RSP: 002b:00007fdad97b1038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: fffffffffffffffe RBX: 00007fdad8be5fa0 RCX: 00007fdad898f749 RDX: 0000200000000200 RSI: 00002000000001c0 RDI: 0000000000000000 RBP: 00007fdad8a13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdad8be6038 R14: 00007fdad8be5fa0 R15: 00007ffdcd75ce28 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e3c9620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e3c9620 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e3c9620 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 2 locks held by getty/5581: #0: ffff88814d7730a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x1510 drivers/tty/n_tty.c:2211 3 locks held by kworker/1:13/10234: 2 locks held by syz-executor/14327: #0: ffff8880780960e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff8880780960e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff8880780960e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff8880780960e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e802048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575 2 locks held by syz-executor/18096: #0: ffff888027a0e0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff888027a0e0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff888027a0e0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff888027a0e0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e802048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575 2 locks held by syz-executor/22600: #0: ffff888056ad40e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff888056ad40e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff888056ad40e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff888056ad40e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e802048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575 4 locks held by udevd/24530: #0: ffff8880738452f0 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12d0 fs/seq_file.c:182 #1: ffff88803462c488 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff888075a1a3c8 (kn->active#19){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888075a1a3c8 (kn->active#19){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff888078d4c198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:900 [inline] #3: ffff888078d4c198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 2 locks held by syz.8.5347/25517: #0: ffffffff901e4ed0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e802048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1ae0 fs/nfsd/nfsctl.c:1880 2 locks held by syz.0.5376/25619: #0: ffff88801ff9e0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88801ff9e0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88801ff9e0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff88801ff9e0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e802048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575 2 locks held by syz-executor/25884: #0: ffff888029f180e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff888029f180e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff888029f180e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff888029f180e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e802048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575 2 locks held by syz-executor/26101: #0: ffff88807befa0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88807befa0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88807befa0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff88807befa0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e802048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575 2 locks held by syz-executor/26470: #0: ffff88804ba2e0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88804ba2e0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88804ba2e0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff88804ba2e0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e802048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575 2 locks held by syz-executor/26674: #0: ffff888030a440e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff888030a440e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff888030a440e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff888030a440e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e802048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575 2 locks held by syz-executor/27007: #0: ffff88802a4ba0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88802a4ba0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88802a4ba0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff88802a4ba0e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e802048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575 2 locks held by syz-executor/27255: #0: ffff8880768660e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff8880768660e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff8880768660e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff8880768660e0 (&type->s_umount_key#97){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e802048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575 5 locks held by kworker/0:6/27818: #0: ffff888020ee3948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232 #1: ffffc90003467c90 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233 #2: ffff888144759198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #2: ffff888144759198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1c0/0x52f0 drivers/usb/core/hub.c:5899 #3: ffff888078d4c198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #3: ffff888078d4c198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4e0 drivers/base/dd.c:1006 #4: ffff888143f7f468 (hcd->bandwidth_mutex){+.+.}-{4:4}, at: usb_set_configuration+0x616/0x1e50 drivers/usb/core/message.c:2077 3 locks held by kworker/u9:1/28099: #0: ffff88807bd06148 ((wq_completion)hci7){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232 #1: ffffc90003f8fc90 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233 #2: ffff888063e88ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x175/0x470 net/bluetooth/hci_sync.c:331 3 locks held by syz.9.5695/28181: #0: ffff88807a7dcec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xc0 net/bluetooth/hci_core.c:499 #1: ffff88807a7dc0c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x3af/0x1260 net/bluetooth/hci_sync.c:5314 #2: ffffffff903bb848 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2143 [inline] #2: ffffffff903bb848 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x290 net/bluetooth/hci_conn.c:2637 3 locks held by syz.7.5697/28195: #0: ffff888077330ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xc0 net/bluetooth/hci_core.c:499 #1: ffff8880773300c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x3af/0x1260 net/bluetooth/hci_sync.c:5314 #2: ffffffff903bb848 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2143 [inline] #2: ffffffff903bb848 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x290 net/bluetooth/hci_conn.c:2637 5 locks held by syz.1.5699/28196: #0: ffff88806c234ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xc0 net/bluetooth/hci_core.c:499 #1: ffff88806c2340c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x3af/0x1260 net/bluetooth/hci_sync.c:5314 #2: ffffffff903bb848 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2143 [inline] #2: ffffffff903bb848 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x290 net/bluetooth/hci_conn.c:2637 #3: ffff88805603f338 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x80/0x760 net/bluetooth/l2cap_core.c:1763 #4: ffffffff8e3d4d78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311 3 locks held by syz.4.5700/28202: #0: ffff8880888f8ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xc0 net/bluetooth/hci_core.c:499 #1: ffff8880888f80c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x3af/0x1260 net/bluetooth/hci_sync.c:5314 #2: ffffffff903bb848 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2143 [inline] #2: ffffffff903bb848 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x290 net/bluetooth/hci_conn.c:2637 ============================================= 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 10/25/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x133/0x180 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xe66/0x1180 kernel/hung_task.c:515 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 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: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:trace_hardirqs_on+0xb/0x40 kernel/trace/trace_preemptirq.c:72 Code: aa 61 00 eb a4 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 8b 05 99 3d ec 11 <85> c0 75 0e e8 bc bf d2 ff 48 8b 3c 24 e9 73 4b b0 09 48 8b 3c 24 RSP: 0018:ffffc90000007bd0 EFLAGS: 00000006 RAX: 0000000000000001 RBX: ffff8881443a0000 RCX: ffffffff819a45a3 RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffff8881443a0000 RBP: 0000000000000246 R08: 0000000000000000 R09: ffffed1028874000 R10: ffff8881443a0003 R11: ffffffff9ae25ea8 R12: 0000000000000000 R13: dffffc0000000000 R14: 1ffff92000000fad R15: ffff88802964f418 FS: 0000000000000000(0000) GS:ffff8881248fd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000404030 CR3: 000000000e184000 CR4: 00000000003526f0 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x52/0x80 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] dummy_timer+0x1e8b/0x3ad0 drivers/usb/gadget/udc/dummy_hcd.c:2012 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x202/0xc40 kernel/time/hrtimer.c:1841 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1858 handle_softirqs+0x219/0x950 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 46 60 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 13 f9 12 00 fb f4 cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c6 RAX: 000000000643842f RBX: 0000000000000000 RCX: ffffffff8b7766d9 RDX: 0000000000000000 RSI: ffffffff8dacb64c RDI: ffffffff8bf2a580 RBP: fffffbfff1c12f68 R08: 0000000000000001 R09: ffffed101708673d R10: ffff8880b84339eb R11: ffffffff8e098670 R12: 0000000000000000 R13: ffffffff8e097b40 R14: ffffffff908878d0 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x38d/0x510 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 rest_init+0x16b/0x2b0 init/main.c:757 start_kernel+0x3ef/0x4d0 init/main.c:1206 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x148