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: ffff88801dedbd48 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#0: ffff88801dedbd48 ((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: ffff88802604ad18 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline]
#2: ffff88802604ad18 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline]
#2: ffff88802604ad18 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x31f/0x4f0 block/blk-mq.c:2386
#3: ffff888026360380 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc6/0x1100 drivers/block/nbd.c:1199
2 locks held by kworker/1:0/24:
#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: ffffc900001e7c40 (free_ipc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
#1: ffffc900001e7c40 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
1 lock held by khungtaskd/30:
#0: ffffffff8e75e520 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e75e520 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e75e520 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
5 locks held by kworker/u8:3/49:
2 locks held by klogd/5182:
#0: ffff8880b863ade0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:647
#1: ffff8880b8624588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933
2 locks held by getty/5583:
#0: ffff888036c910a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5823:
#0: ffffffff8e7647b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#0: ffffffff8e7647b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
5 locks held by syz-executor/5825:
#0: ffff88801b350ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:500 [inline]
#0: ffff88801b350ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x5a0 net/bluetooth/hci_core.c:2716
#1: ffff88801b3500c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x640/0x10e0 net/bluetooth/hci_sync.c:5346
#2: ffffffff8fd5abe8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2151 [inline]
#2: ffffffff8fd5abe8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x260 net/bluetooth/hci_conn.c:2644
#3: ffff888077388b00 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x7b/0x5c0 net/bluetooth/l2cap_core.c:1774
#4: ffffffff8e7647b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#4: ffffffff8e7647b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
1 lock held by udevd/5834:
#0: ffff8880262f3358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:961
1 lock held by udevd/5843:
#0: ffff8880262f7358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:961
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5824 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:rcu_is_watching+0x70/0xb0 kernel/rcu/tree.c:754
Code: c3 58 69 1d 93 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 34 8b 03 65 ff 0d 69 7b 71 11 74 11 83 e0 04 c1 e8 02 5b <41> 5e 41 5f e9 c7 b3 06 0a cc e8 51 f9 88 ff eb e8 48 c7 c7 00 4a
RSP: 0018:ffffc90003fe7780 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffc90003fe7801 RCX: 0000000080000001
RDX: ffffffff90a0ca01 RSI: ffffffff8c27c1e0 RDI: ffffffff8c27c1a0
RBP: dffffc0000000000 R08: ffffc90003fe78c7 R09: 0000000000000000
R10: ffffc90003fe78b8 R11: fffff520007fcf19 R12: ffffc90003fe7ef0
R13: ffffc90003fe0000 R14: ffffffff8e1b0790 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff88812545d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005604d4a32ee8 CR3: 000000000e54c000 CR4: 00000000003526f0
Call Trace:
rcu_read_unlock include/linux/rcupdate.h:879 [inline]
class_rcu_destructor include/linux/rcupdate.h:1193 [inline]
unwind_next_frame+0x1a66/0x23c0 arch/x86/kernel/unwind_orc.c:695
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
save_stack+0x122/0x230 mm/page_owner.c:165
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1433 [inline]
__free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
vfree+0x25a/0x400 mm/vmalloc.c:3479
kcov_put kernel/kcov.c:442 [inline]
kcov_close+0x28/0x50 kernel/kcov.c:543
__fput+0x44f/0xa70 fs/file_table.c:469
task_work_run+0x1d9/0x270 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x70f/0x23c0 kernel/exit.c:976
do_group_exit+0x21b/0x2d0 kernel/exit.c:1118
__do_sys_exit_group kernel/exit.c:1129 [inline]
__se_sys_exit_group kernel/exit.c:1127 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1127
x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f09abb9c799
Code: Unable to access opcode bytes at 0x7f09abb9c76f.
RSP: 002b:00007ffc925e2938 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f09abc33be1 RCX: 00007f09abb9c799
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000043
RBP: 00007f09abc33bf3 R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
R13: 00000000000927c0 R14: 000000000006b5fb R15: 00007ffc925e2ae0