INFO: task udevd:4411 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:23584 pid:4411 ppid:3636 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
device_lock include/linux/device.h:840 [inline]
uevent_show+0x16c/0x320 drivers/base/core.c:2669
dev_attr_show+0x50/0xb0 drivers/base/core.c:2372
sysfs_kf_seq_show+0x349/0x4b0 fs/sysfs/file.c:59
seq_read_iter+0x49b/0xd50 fs/seq_file.c:230
call_read_iter include/linux/fs.h:2259 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x434/0x920 fs/read_write.c:470
ksys_read+0x143/0x240 fs/read_write.c:613
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3d82aa7407
RSP: 002b:00007ffe40f57c10 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f3d83219880 RCX: 00007f3d82aa7407
RDX: 0000000000001000 RSI: 0000564c9b8c6860 RDI: 0000000000000008
RBP: 00007f3d82befff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007f3d82befea0 R14: 0000000000000000 R15: 0000564c9b8617a0
Showing all locks held in the system:
4 locks held by kworker/u4:1/11:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8c92bab0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8c92c2d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
3 locks held by kworker/1:1/26:
1 lock held by khungtaskd/28:
#0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by getty/4028:
#0: ffff88814c92a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
2 locks held by syz-executor/4264:
#0: ffff8880797590b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:508 [inline]
#0: ffff8880797590b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x1fa/0x4f0 net/bluetooth/hci_core.c:2705
#1: ffff888079758078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x458/0xf40 net/bluetooth/hci_sync.c:5233
1 lock held by syz-executor/4266:
#0: ffff88807978d0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:508 [inline]
#0: ffff88807978d0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x1fa/0x4f0 net/bluetooth/hci_core.c:2705
3 locks held by kworker/0:4/4344:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc90004a47d00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffffffff8db3b3a8 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:104
3 locks held by kworker/u4:9/4385:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc90004befd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffffffff8db3b3a8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263
4 locks held by udevd/4411:
#0: ffff88804871bb08 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xad/0xd50 fs/seq_file.c:182
#1: ffff88805707c088 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x58/0x410 fs/kernfs/file.c:172
#2: ffff88805e400a00 (kn->active#5){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff88805e400a00 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0xae/0x410 fs/kernfs/file.c:173
#3: ffff888143a89190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:840 [inline]
#3: ffff888143a89190 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16c/0x320 drivers/base/core.c:2669
6 locks held by kworker/1:11/4617:
#0: ffff8881436d3138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc90005ae7d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffff888027e4c190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:840 [inline]
#2: ffff888027e4c190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1a7/0x54e0 drivers/usb/core/hub.c:5845
#3: ffff888143a89190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:840 [inline]
#3: ffff888143a89190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x460 drivers/base/dd.c:990
#4: ffff88802c096118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:840 [inline]
#4: ffff88802c096118 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x460 drivers/base/dd.c:990
#5: ffffffff8c7d7cd0 (umhelper_sem){++++}-{3:3}, at: usermodehelper_read_trylock+0xec/0x2a0 kernel/umh.c:218
2 locks held by kworker/0:15/5192:
#0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc9000d81fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
3 locks held by syz.4.612/7759:
#0: ffff8880246cd0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:508 [inline]
#0: ffff8880246cd0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x1fa/0x4f0 net/bluetooth/hci_core.c:2705
#1: ffff8880246cc078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x458/0xf40 net/bluetooth/hci_sync.c:5233
#2: ffffffff8dc98f48 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1826 [inline]
#2: ffffffff8dc98f48 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xac/0x290 net/bluetooth/hci_conn.c:2504
1 lock held by syz-executor/7976:
#0: ffffffff8db3b3a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
#0: ffffffff8db3b3a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x740/0xed0 net/core/rtnetlink.c:6147
3 locks held by syz.2.667/8034:
#0: ffff8880785a10b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:508 [inline]
#0: ffff8880785a10b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x1fa/0x4f0 net/bluetooth/hci_core.c:2705
#1: ffff8880785a0078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x458/0xf40 net/bluetooth/hci_sync.c:5233
#2: ffffffff8dc98f48 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1826 [inline]
#2: ffffffff8dc98f48 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xac/0x290 net/bluetooth/hci_conn.c:2504
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xeee/0xf30 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4882 Comm: kworker/u4:32 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:pie_calculate_probability+0x4fe/0x7d0 net/sched/sch_pie.c:409
Code: 6c 24 58 73 64 48 89 e8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 ef e8 11 0d 86 f9 4c 8b 7d 00 4c 89 ff 48 89 de e8 92 dd 35 f9 <49> 39 df 73 49 48 8b 44 24 18 42 80 3c 20 00 74 08 4c 89 f7 e8 e9
RSP: 0018:ffffc900001e0a70 EFLAGS: 00000246
RAX: ffffffff884b041e RBX: 000000000001c9c3 RCX: ffff88807b70d940
RDX: 0000000000000100 RSI: 000000000001c9c3 RDI: 0000000000000000
RBP: ffff888065eaa958 R08: 0000000000000004 R09: 0000000000000003
R10: fffff5200003c150 R11: 1ffff9200003c150 R12: dffffc0000000000
R13: ffff888029db031a R14: ffff888065eaa970 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f08937b42f8 CR3: 000000000c68e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
fq_pie_timer+0x281/0x5a0 net/sched/sch_fq_pie.c:391
call_timer_fn+0x1a0/0x670 kernel/time/timer.c:1701
expire_timers kernel/time/timer.c:1752 [inline]
__run_timers+0x529/0x7d0 kernel/time/timer.c:2023
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:check_kcov_mode kernel/kcov.c:184 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x2c/0x60 kernel/kcov.c:216
Code: 04 24 65 48 8b 0d 64 8f 81 7e 65 8b 15 65 8f 81 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c <8b> 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48
RSP: 0018:ffffc90004c1f698 EFLAGS: 00000246
RAX: ffffffff81d141a4 RBX: ffff88823bcf3000 RCX: ffff88807b70d940
RDX: 0000000000000000 RSI: ffff88823bcf3000 RDI: ffff88823bcf20f0
RBP: ffffc90004c1f7b0 R08: dffffc0000000000 R09: fffff940011de791
R10: fffff940011de791 R11: 1ffffd40011de790 R12: dffffc0000000000
R13: ffff88823bcf2000 R14: ffff88823bcf29f8 R15: ffff8881401ec000
for_each_canary mm/kfence/core.c:350 [inline]
kfence_guarded_alloc+0x754/0xcf0 mm/kfence/core.c:439
__kfence_alloc+0x369/0x3a0 mm/kfence/core.c:1050
kfence_alloc include/linux/kfence.h:128 [inline]
slab_alloc_node mm/slub.c:3283 [inline]
kmem_cache_alloc_node+0x2b5/0x320 mm/slub.c:3404
__alloc_skb+0xfc/0x7e0 net/core/skbuff.c:505
alloc_skb include/linux/skbuff.h:1271 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline]
nsim_dev_trap_report_work+0x28f/0xaf0 drivers/net/netdevsim/dev.c:851
process_one_work+0x898/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295