INFO: task kworker/0:1H:57 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:1H state:D stack:26520 pid:57 tgid:57 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: kblockd blk_mq_run_work_fn
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x16dc/0x5500 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
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+0x889/0x1150 drivers/block/nbd.c:1207
blk_mq_dispatch_rq_list+0x4af/0x1a00 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+0xd45/0x1590 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xda/0x1a0 block/blk-mq-sched.c:329
blk_mq_run_work_fn+0x16f/0x300 block/blk-mq.c:2532
process_one_work kernel/workqueue.c:3322 [inline]
process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
kthread+0x388/0x470 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:
4 locks held by pr/legacy/17:
1 lock held by khungtaskd/38:
#0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
6 locks held by kworker/u8:3/56:
4 locks held by kworker/0[ 620.582384][ T38] 4 locks held by kworker/0:1H/57:
#0: ffff88801d6b9938 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801d6b9938 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc9000123fc40 ((work_completion)(&(&hctx->run_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc9000123fc40 ((work_completion)(&(&hctx->run_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffff888026c0b318 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline]
#2: ffff888026c0b318 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline]
#2: ffff888026c0b318 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_work_fn+0x147/0x300 block/blk-mq.c:2531
#3: ffff888026dc7170 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc1/0x1150 drivers/block/nbd.c:1199
4 locks held by kworker/1:1H/71:
2 locks held by getty/5337:
#0: ffff8880320690a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
5 locks held by syz-executor/5583:
5 locks held by kworker/1:5/5718:
4 locks held by kworker/1:2H/5820:
#0: ffff88801d6b9938 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801d6b9938 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc900057afc40 ((work_completion)(&(&hctx->run_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc900057afc40 ((work_completion)(&(&hctx->run_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffff888026c0b098 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline]
#2: ffff888026c0b098 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline]
#2: ffff888026c0b098 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_work_fn+0x147/0x300 block/blk-mq.c:2531
#3: ffff888026df0170 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc1/0x1150 drivers/block/nbd.c:1199
5 locks held by kworker/u8:14/5858:
1 lock held by udevd/9091:
#0: ffff88802543f4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd00 block/bdev.c:948
1 lock held by udevd/9096:
#0: ffff8880263074c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd00 block/bdev.c:948
5 locks held by kworker/0:0H/9102:
1 lock held by udevd/9209:
4 locks held by udevd/9275:
4 locks held by syz.6.1194/10732:
3 locks held by iou-sqp-10764/10765:
4 locks held by syz.2.1206/10768:
1 lock held by syz.2.1206/10776:
#0: ffffffff8e9517f8 (crypto_cfg_mutex){+.+.}-{4:4}, at: crypto_netlink_rcv+0x1b/0x40 crypto/crypto_user.c:463
1 lock held by syz.2.1206/10778:
1 lock held by syz.5.1205/10771:
1 lock held by syz.5.1205/10777:
1 lock held by syz.5.1205/10779:
#0: ffffffff8e9517f8 (crypto_cfg_mutex){+.+.}-{4:4}, at: crypto_netlink_rcv+0x1b/0x40 crypto/crypto_user.c:463
2 locks held by syz.5.1205/10781:
#0: ffffffff8e2c6d58 (pcpu_alloc_mutex){+.+.}-{4:4}, at: pcpu_alloc_noprof+0x239/0x18d0 mm/percpu.c:1788
#1: ffffffff8e2c66f8 (pcpu_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#1: ffffffff8e2c66f8 (pcpu_lock){+.+.}-{3:3}, at: pcpu_alloc_noprof+0x2e8/0x18d0 mm/percpu.c:1794
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
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:122
nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
trigger_all_cpu_backtrace include/linux/nmi.h:162 [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+0x388/0x470 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 17 Comm: pr/legacy Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 ee 1f 70 fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 4f 96 d9 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90000167a28 EFLAGS: 00000202
RAX: 1ffffffff33c8c00 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff8555a7f0 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99e46340 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125c46000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f33a7d21d58 CR3: 000000003b00a000 CR4: 00000000003526f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x190/0x300 drivers/tty/serial/8250/8250_port.c:1982
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3235 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3300 [inline]
serial8250_console_write+0x113a/0x1b40 drivers/tty/serial/8250/8250_port.c:3385
console_emit_next_record kernel/printk/printk.c:3163 [inline]
console_flush_one_record+0x642/0xb50 kernel/printk/printk.c:3269
legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712
kthread+0x388/0x470 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