INFO: task udevd:11829 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:23256 pid:11829 tgid:11829 ppid:5003 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7283
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_dispatch_list+0xd16/0xe10 include/linux/spinlock.h:-1
blk_mq_flush_plug_list+0x48d/0x570 block/blk-mq.c:2997
__blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1230
blk_finish_plug block/blk-core.c:1257 [inline]
__submit_bio+0x28d/0x580 block/blk-core.c:649
__submit_bio_noacct_mq block/blk-core.c:722 [inline]
submit_bio_noacct_nocheck+0x2f4/0xa40 block/blk-core.c:753
submit_bh fs/buffer.c:2742 [inline]
block_read_full_folio+0x7b7/0x830 fs/buffer.c:2358
filemap_read_folio+0x137/0x3b0 mm/filemap.c:2502
do_read_cache_folio+0x358/0x590 mm/filemap.c:4107
read_mapping_folio include/linux/pagemap.h:1017 [inline]
read_part_sector+0xb6/0x2b0 block/partitions/core.c:724
adfspart_check_ICS+0xb1/0x960 block/partitions/acorn.c:356
check_partition block/partitions/core.c:143 [inline]
blk_add_partitions block/partitions/core.c:591 [inline]
bdev_disk_changed+0x817/0x1770 block/partitions/core.c:695
blkdev_get_whole+0x380/0x510 block/bdev.c:756
bdev_open+0x31e/0xd30 block/bdev.c:965
blkdev_open+0x470/0x610 block/fops.c:697
do_dentry_open+0x822/0x13a0 fs/open.c:947
vfs_open+0x3b/0x340 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x2e08/0x3860 fs/namei.c:4858
do_file_open+0x23e/0x4a0 fs/namei.c:4887
do_sys_openat2+0x113/0x200 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_sys_openat fs/open.c:1386 [inline]
__se_sys_openat fs/open.c:1381 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1381
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f79698a7407
RSP: 002b:00007ffe5828cf90 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f7969fc9880 RCX: 00007f79698a7407
RDX: 00000000000a0800 RSI: 000055842fb8d520 RDI: ffffffffffffff9c
RBP: 000055842fb76910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055842fb93f10
R13: 000055842fb84190 R14: 0000000000000000 R15: 000055842fb93f10
Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8e95cc20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e95cc20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8e95cc20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:8/1332:
#0: ffff88801be8e140 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88801be8e140 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9000613fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9000613fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
#2: ffffffff8e962df8 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
2 locks held by getty/5392:
#0: ffff8880363970a0 (&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+0x45c/0x13a0 drivers/tty/n_tty.c:2211
2 locks held by sshd-session/5621:
3 locks held by kworker/0:7/5832:
#0: ffff88813fe43140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88813fe43140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc900051e7c40 (free_ipc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc900051e7c40 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
#2: ffffffff8e962f28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#2: ffffffff8e962f28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
3 locks held by kworker/0:11/10297:
#0: ffff88813fe43140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88813fe43140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9000e1ffc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9000e1ffc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
#2: ffff88802a508250 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x202/0x3d0 drivers/net/netdevsim/fib.c:1490
7 locks held by kworker/1:13/10314:
3 locks held by udevd/11829:
#0: ffff888026391350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:953
#1: ffff88802509a018 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline]
#1: ffff88802509a018 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline]
#1: ffff88802509a018 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x31f/0x4f0 block/blk-mq.c:2386
#2: ffff8880273851f8 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc6/0x1100 drivers/block/nbd.c:1199
1 lock held by syz-executor/18631:
#0: ffff88808d388ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:500 [inline]
#0: ffff88808d388ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x5a0 net/bluetooth/hci_core.c:2679
2 locks held by syz.5.3302/19555:
1 lock held by syz-executor/19575:
1 lock held by syz.0.3318/19621:
2 locks held by dhcpcd-run-hook/19641:
=============================================
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 05/09/2026
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: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+0xfd3/0x1030 kernel/hung_task.c:561
kthread+0x389/0x470 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6401 Comm: kworker/u8:19 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:217 [inline]
RIP: 0010:unwind_next_frame+0x1c6/0x2550 arch/x86/kernel/unwind_orc.c:510
Code: 24 10 74 08 4c 89 ff e8 18 2c ba 00 4d 8b 27 48 83 f3 01 48 c7 c2 20 a5 c9 8b 49 29 dc 0f 84 b2 02 00 00 49 81 fc 00 00 00 81 <0f> 92 c0 49 81 fc 18 8c ad 8b 0f 93 c1 08 c1 0f 85 05 01 00 00 48
RSP: 0018:ffffc90000a08718 EFLAGS: 00000206
RAX: 1ffff92000141112 RBX: 0000000000000001 RCX: 0000000000000103
RDX: ffffffff8bc9a520 RSI: ffffffff8c28b9c0 RDI: ffffffff8c28b980
RBP: dffffc0000000000 R08: ffffffff8176e256 R09: ffffffff8e95cc20
R10: ffffc90000a08898 R11: fffff52000141115 R12: ffffffff816d74b2
R13: 1ffff92000141109 R14: ffffc90000a08848 R15: ffffc90000a08890
FS: 0000000000000000(0000) GS:ffff88812538b000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005634bf80d950 CR3: 000000000e74a000 CR4: 00000000003526f0
Call Trace:
__unwind_start+0x5b8/0x760 arch/x86/kernel/unwind_orc.c:787
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2689 [inline]
slab_free mm/slub.c:6251 [inline]
kfree+0x1c5/0x640 mm/slub.c:6566
ref_tracker_free+0x522/0x840 lib/ref_tracker.c:339
netdev_tracker_free include/linux/netdevice.h:4501 [inline]
netdev_put include/linux/netdevice.h:4518 [inline]
dst_destroy+0x10f/0x350 net/core/dst.c:115
rcu_do_batch kernel/rcu/tree.c:2617 [inline]
rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869
handle_softirqs+0x22a/0x840 kernel/softirq.c:622
do_softirq+0x76/0xd0 kernel/softirq.c:523
__local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
spin_unlock_bh include/linux/spinlock.h:396 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:891 [inline]
nsim_dev_trap_report_work+0x7d6/0xb90 drivers/net/netdevsim/dev.c:922
process_one_work kernel/workqueue.c:3314 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
kthread+0x389/0x470 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