INFO: task kworker/0:0H:11 blocked for more than 143 seconds. Not tainted syzkaller #0 Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:0H state:D stack:25928 pid:11 tgid:11 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: kblockd blk_mq_run_work_fn Call Trace: context_switch kernel/sched/core.c:5526 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7276 __schedule_loop kernel/sched/core.c:7353 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7368 schedule_timeout+0x152/0x2c0 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+0x96f/0xff0 drivers/block/nbd.c:1207 blk_mq_dispatch_rq_list+0x499/0x1990 block/blk-mq.c:2117 __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+0xd36/0x1580 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329 blk_mq_run_work_fn+0x16c/0x300 block/blk-mq.c:2532 process_one_work kernel/workqueue.c:3396 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: locks held by kworker/0:1/10: 2, last CPU#0: #0: ffff88807a223140 ((wq_completion)wg-crypt-wg2#11){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffff88807a223140 ((wq_completion)wg-crypt-wg2#11){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffff88807a223140 ((wq_completion)wg-crypt-wg2#11){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline] #0: ffff88807a223140 ((wq_completion)wg-crypt-wg2#11){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479 #1: ffffc900000f7c40 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #1: ffffc900000f7c40 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffc900000f7c40 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline] #1: ffffc900000f7c40 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479 locks held by kworker/0:0H/11: 4, on CPU#0: #0: ffff88801fea3d40 ((wq_completion)kblockd){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffff88801fea3d40 ((wq_completion)kblockd){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffff88801fea3d40 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline] #0: ffff88801fea3d40 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479 #1: ffffc90000107c40 ((work_completion)(&(&hctx->run_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #1: ffffc90000107c40 ((work_completion)(&(&hctx->run_work)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffc90000107c40 ((work_completion)(&(&hctx->run_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline] #1: ffffc90000107c40 ((work_completion)(&(&hctx->run_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479 #2: ffff8880266a9f18 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:198 [inline] #2: ffff8880266a9f18 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:305 [inline] #2: ffff8880266a9f18 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_work_fn+0x144/0x300 block/blk-mq.c:2531 #3: ffff888026e451f8 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc1/0xff0 drivers/block/nbd.c:1199 locks held by khungtaskd/32: 1, last CPU#0: #0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871 locks held by getty/5364: 2, on CPU#0: #0: ffff888035c0e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211 locks held by kworker/u8:40/10448: 5, last CPU#0: #0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline] #0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479 #1: ffffc90003207c40 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #1: ffffc90003207c40 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffc90003207c40 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline] #1: ffffc90003207c40 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479 #2: ffffffff8ebe98f0 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_enable+0x12/0x20 kernel/jump_label.c:222 #3: ffffffff8ee388a0 (jump_label_mutex){+.+.}-{4:4}, at: jump_label_lock kernel/jump_label.c:27 [inline] #3: ffffffff8ee388a0 (jump_label_mutex){+.+.}-{4:4}, at: static_key_enable_cpuslocked+0xcb/0x240 kernel/jump_label.c:207 #4: ffffffff8ebff6a0 (text_mutex){+.+.}-{4:4}, at: arch_jump_label_transform_apply+0x17/0x30 arch/x86/kernel/jump_label.c:145 locks held by kworker/u8:61/10470: 2, last CPU#0: #0: ffff888054d2b940 ((wq_completion)wg-kex-wg2#21){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffff888054d2b940 ((wq_completion)wg-kex-wg2#21){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffff888054d2b940 ((wq_completion)wg-kex-wg2#21){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline] #0: ffff888054d2b940 ((wq_completion)wg-kex-wg2#21){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479 #1: ffffc90002df7c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #1: ffffc90002df7c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffc90002df7c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline] #1: ffffc90002df7c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479 locks held by kworker/u8:83/10496: 5, last CPU#1: #0: ffff88802ca5d140 ((wq_completion)krds_cp_wq#17/6){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffff88802ca5d140 ((wq_completion)krds_cp_wq#17/6){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffff88802ca5d140 ((wq_completion)krds_cp_wq#17/6){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline] #0: ffff88802ca5d140 ((wq_completion)krds_cp_wq#17/6){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479 #1: ffffc90003a97c40 ((work_completion)(&(&cp->cp_conn_w)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #1: ffffc90003a97c40 ((work_completion)(&(&cp->cp_conn_w)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffc90003a97c40 ((work_completion)(&(&cp->cp_conn_w)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline] #1: ffffc90003a97c40 ((work_completion)(&(&cp->cp_conn_w)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479 #2: ffff888052098c80 (&tc->t_conn_path_lock){+.+.}-{4:4}, at: rds_tcp_conn_path_connect+0x1cc/0x920 net/rds/tcp_connect.c:118 #3: ffff888052491d60 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline] #3: ffff888052491d60 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: __inet6_bind+0x301/0xf30 net/ipv6/af_inet6.c:292 #4: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #4: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #4: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: __inet6_bind+0x49b/0xf30 net/ipv6/af_inet6.c:336 locks held by udevd/27275: 1, on CPU#0: #0: ffff888026d9b350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123 nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66 trigger_all_cpu_backtrace include/linux/nmi.h:164 [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:353 [inline] watchdog+0xfd7/0x1030 kernel/hung_task.c:561 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 16 Comm: pr/ttyS0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:delay_tsc+0x5d/0xd0 arch/x86/lib/delay.c:77 Code: 89 d7 49 c1 e7 20 49 09 c7 4d 29 f7 49 39 df 73 55 bf 01 00 00 00 e8 82 fa b0 f5 65 48 8b 05 fa 08 b1 07 48 85 c0 74 1c f3 90 01 00 00 00 e8 19 f9 b0 f5 e8 f4 7a 01 00 39 c5 75 0e 0f 01 f9 RSP: 0018:ffffc900001578b8 EFLAGS: 00000082 RAX: 8000000000000001 RBX: 0000000000000899 RCX: ffffffff9a9e3501 RDX: 0000000000000101 RSI: ffffffff8c6d9c60 RDI: 00000000ffffffff RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: ffffffff8be3e6c0 R12: 1ffffffff35a746d R13: 00000000ffffffff R14: 000001aab3d84088 R15: 0000000000000112 FS: 0000000000000000(0000) GS:ffff888124dd1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055eb18952660 CR3: 000000007e56e000 CR4: 00000000003526f0 Call Trace: udelay include/asm-generic/delay.h:62 [inline] wait_for_lsr+0x147/0x2f0 drivers/tty/serial/8250/8250_port.c:2019 serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3270 [inline] __serial8250_console_fifo_write+0xcd/0x3e0 drivers/tty/serial/8250/8250_port.c:3345 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3378 [inline] __serial8250_console_write drivers/tty/serial/8250/8250_port.c:3429 [inline] serial8250_console_write+0xaa1/0x1200 drivers/tty/serial/8250/8250_port.c:3493 nbcon_emit_next_record+0xef5/0x1a90 kernel/printk/nbcon.c:-1 nbcon_emit_one kernel/printk/nbcon.c:1157 [inline] nbcon_kthread_func+0x679/0x880 kernel/printk/nbcon.c:1271 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245