INFO: task udevd:9673 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:23400 pid:9673 tgid:9673 ppid:4999 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+0x174/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f857c8a7407
RSP: 002b:00007ffd10f33990 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f857cfe5880 RCX: 00007f857c8a7407
RDX: 00000000000a0800 RSI: 00005602c5d0b520 RDI: ffffffffffffff9c
RBP: 00005602c5d0a910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00005602c5d27f10
R13: 00005602c5d18190 R14: 0000000000000000 R15: 00005602c5d27f10
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u9:0/50:
#0: ffff888027413940 ((wq_completion)nbd3-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff888027413940 ((wq_completion)nbd3-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc90000ba7c40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc90000ba7c40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
9 locks held by kworker/u8:9/3315:
2 locks held by getty/5384:
#0: ffff8880322680a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0 drivers/tty/n_tty.c:2211
2 locks held by kworker/u9:2/5632:
#0: ffff888027413940 ((wq_completion)nbd3-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff888027413940 ((wq_completion)nbd3-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9000430fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9000430fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
2 locks held by kworker/u9:1/32475:
#0: ffff888027413940 ((wq_completion)nbd3-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff888027413940 ((wq_completion)nbd3-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9000375fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9000375fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
2 locks held by kworker/u9:3/32476:
#0: ffff888027430940 ((wq_completion)nbd4-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff888027430940 ((wq_completion)nbd4-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9000306fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9000306fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
2 locks held by kworker/u9:4/32594:
#0:
ffff888027430940
((wq_completion)nbd4-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
((wq_completion)nbd4-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc90005fa7c40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc90005fa7c40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
2 locks held by kworker/u9:5/32644:
#0: ffff888027430940 ((wq_completion)nbd4-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff888027430940 ((wq_completion)nbd4-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9000353fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9000353fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
2 locks held by kworker/u9:6/32645:
#0: ffff888027435940 ((wq_completion)nbd5-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff888027435940 ((wq_completion)nbd5-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9000307fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9000307fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
2 locks held by kworker/u9:7/32661:
#0: ffff888027435940 ((wq_completion)nbd5-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff888027435940 ((wq_completion)nbd5-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9001b967c40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9001b967c40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
2 locks held by kworker/u9:8/32696:
#0: ffff888027435940 ((wq_completion)nbd5-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff888027435940 ((wq_completion)nbd5-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc900044dfc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc900044dfc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
2 locks held by kworker/u9:9/32697:
#0: ffff888027512940 ((wq_completion)nbd6-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff888027512940 ((wq_completion)nbd6-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc900043dfc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc900043dfc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
2 locks held by kworker/u9:10/322:
#0: ffff888027512940 ((wq_completion)nbd6-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff888027512940 ((wq_completion)nbd6-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9000464fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9000464fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
2 locks held by kworker/u9:11/323:
#0: ffff888027512940 ((wq_completion)nbd6-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff888027512940 ((wq_completion)nbd6-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9000433fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9000433fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
2 locks held by kworker/u9:12/324:
#0: ffff88802758c940 ((wq_completion)nbd8-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88802758c940 ((wq_completion)nbd8-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc90003a1fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc90003a1fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
2 locks held by kworker/u9:13/339:
#0: ffff88802758c940 ((wq_completion)nbd8-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88802758c940 ((wq_completion)nbd8-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9000470fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9000470fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
2 locks held by kworker/u9:14/525:
#0: ffff88802758c940 ((wq_completion)nbd8-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88802758c940 ((wq_completion)nbd8-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9000555fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9000555fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
3 locks held by udevd/9673:
#0: ffff88807e397350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:953
#1: ffff8880737bd118 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline]
#1: ffff8880737bd118 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline]
#1: ffff8880737bd118 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x31f/0x4f0 block/blk-mq.c:2386
#2: ffff88807aeb0178 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc6/0x1100 drivers/block/nbd.c:1199
2 locks held by syz.4.19165/15548:
#0: ffffffff8fdb98a8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575
#1: ffffffff8e962fa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#1: ffffffff8e962fa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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: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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 15548 Comm: syz.4.19165 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:__lock_acquire+0x867/0x2cf0 kernel/locking/lockdep.c:-1
Code: 89 ca c1 c2 06 31 da 01 c1 29 d0 89 d6 c1 c6 08 31 c6 01 ca 29 f1 89 f3 c1 c3 10 31 cb 01 d6 29 da 89 dd c1 c5 13 31 d5 01 f3 <29> ee 01 eb c1 c5 04 31 f5 48 c1 e5 20 83 3d 49 eb 8e 0e 00 4d 89
RSP: 0018:ffffc9001b2e70f0 EFLAGS: 00000013
RAX: 00000000241d244e RBX: 000000001ad9ef43 RCX: 00000000d7c084a2
RDX: 00000000cfa7da9b RSI: 000000005d6f9a44 RDI: ffff888026ed0000
RBP: 00000000685a31c9 R08: ffffffff8176f256 R09: ffffffff8e95cca0
R10: ffffc9001b2e73f8 R11: ffffffff81b0f200 R12: ffff888026ed0c30
R13: ffff888026ed0c30 R14: ffff888026ed0000 R15: 0000000000000004
FS: 00007f9b1701e6c0(0000) GS:ffff88812528e000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000946030 CR3: 000000007b304000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock include/linux/rcupdate.h:838 [inline]
class_rcu_constructor include/linux/rcupdate.h:1181 [inline]
unwind_next_frame+0xc3/0x2550 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
__call_rcu_common kernel/rcu/tree.c:3131 [inline]
call_rcu+0xee/0x890 kernel/rcu/tree.c:3251
kernfs_put+0x259/0x520 fs/kernfs/dir.c:618
kernfs_remove_by_name_ns+0xc8/0x140 fs/kernfs/dir.c:1799
device_remove_class_symlinks+0x11f/0x190 drivers/base/core.c:3478
device_del+0x400/0x8f0 drivers/base/core.c:3881
unregister_netdevice_many_notify+0x1b5a/0x20c0 net/core/dev.c:12468
ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
ops_undo_list+0x3d3/0x940 net/core/net_namespace.c:248
setup_net+0x2f0/0x340 net/core/net_namespace.c:462
copy_net_ns+0x50e/0x730 net/core/net_namespace.c:579
create_new_namespaces+0x3e7/0x6a0 kernel/nsproxy.c:132
unshare_nsproxy_namespaces+0x149/0x190 kernel/nsproxy.c:234
ksys_unshare+0x57d/0x9f0 kernel/fork.c:3243
__do_sys_unshare kernel/fork.c:3317 [inline]
__se_sys_unshare kernel/fork.c:3315 [inline]
__x64_sys_unshare+0x38/0x50 kernel/fork.c:3315
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9b1619ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9b1701e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f9b16416090 RCX: 00007f9b1619ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000006a040000
RBP: 00007f9b16232d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9b16416128 R14: 00007f9b16416090 R15: 00007fffb8cfe118