INFO: task kworker/0:0H:11 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:0H state:D stack:26504 pid:11 tgid:11 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: kblockd blk_mq_requeue_work Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x164/0x360 kernel/sched/core.c:7008 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 wait_for_reconnect drivers/block/nbd.c:1107 [inline] nbd_handle_cmd drivers/block/nbd.c:1149 [inline] nbd_queue_rq+0x857/0x1100 drivers/block/nbd.c:1207 blk_mq_dispatch_rq_list+0xa70/0x1910 block/blk-mq.c:2148 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline] __blk_mq_sched_dispatch_requests+0xdcc/0x1600 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2386 blk_mq_run_hw_queues+0x26c/0x3f0 block/blk-mq.c:2435 blk_mq_requeue_work+0x71c/0x780 block/blk-mq.c:1602 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 4 locks held by kworker/0:0H/11: #0: ffff8880206a1548 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #0: ffff8880206a1548 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359 #1: ffffc90000107c40 ((work_completion)(&(&q->requeue_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline] #1: ffffc90000107c40 ((work_completion)(&(&q->requeue_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359 #2: ffff888026803398 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline] #2: ffff888026803398 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline] #2: ffff888026803398 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x31f/0x4f0 block/blk-mq.c:2386 #3: ffff888026b80780 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc6/0x1100 drivers/block/nbd.c:1199 1 lock held by khungtaskd/30: #0: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5585: #0: ffff8880367530a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211 1 lock held by udevd/5838: #0: ffff888026a74358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:961 3 locks held by kworker/1:6/5995: 3 locks held by kworker/1:12/11766: #0: ffff88813fe0f148 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #0: ffff88813fe0f148 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359 #1: ffffc90004f6fc40 (free_ipc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline] #1: ffffc90004f6fc40 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359 #2: ffffffff8e7648b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #2: ffffffff8e7648b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961 1 lock held by syz-executor/17249: 1 lock held by syz.4.3149/17262: 2 locks held by syz.1.3162/17308: #0: ffffffff8fbd4668 (bpf_dispatcher_xdp.mutex){+.+.}-{4:4}, at: bpf_dispatcher_change_prog+0xc6/0xd70 kernel/bpf/dispatcher.c:146 #1: ffffffff8e7648b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #1: ffffffff8e7648b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961 4 locks held by syz.2.3163/17313: #0: ffff888033650ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:500 [inline] #0: ffff888033650ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x5a0 net/bluetooth/hci_core.c:2716 #1: ffff8880336500c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x640/0x10e0 net/bluetooth/hci_sync.c:5356 #2: ffffffff8fd5e328 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2151 [inline] #2: ffffffff8fd5e328 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x260 net/bluetooth/hci_conn.c:2650 #3: ffff88801faa6300 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x92/0x570 net/bluetooth/l2cap_core.c:1777 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 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+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xfd9/0x1030 kernel/hung_task.c:515 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 80 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Workqueue: events_unbound cfg80211_wiphy_work RIP: 0010:constant_test_bit arch/x86/include/asm/bitops.h:202 [inline] RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:232 [inline] RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline] RIP: 0010:ieee80211_iface_work+0xb9/0x1340 net/mac80211/iface.c:1789 Code: b7 40 1b 00 00 4c 89 f7 be 08 00 00 00 e8 4f 0e 10 f7 4c 89 f0 48 c1 e8 03 80 3c 18 00 74 08 4c 89 f7 e8 ca 0b 10 f7 4d 8b 36 <4c> 89 f6 48 83 e6 01 31 ff e8 49 be a5 f6 49 83 e6 01 75 27 4d 8d RSP: 0018:ffffc9000259fa10 EFLAGS: 00000246 RAX: 1ffff11010a78540 RBX: dffffc0000000000 RCX: ffffffff8b200661 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8880853c2a00 RBP: dffffc0000000000 R08: ffff8880853c2a07 R09: 1ffff11010a78540 R10: dffffc0000000000 R11: ffffed1010a78541 R12: ffff88806afa1a88 R13: ffff8880853c06c0 R14: 0000000000000000 R15: ffff8880853c0ec0 FS: 0000000000000000(0000) GS:ffff888125554000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055e8df808ee8 CR3: 000000000e54c000 CR4: 00000000003526f0 Call Trace: cfg80211_wiphy_work+0x2ab/0x4a0 net/wireless/core.c:440 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245