INFO: task udevd:12575 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc1-syzkaller-00082-gf41f7b3d9daf #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:24536 pid:12575 tgid:12575 ppid:2842   task_flags:0x400140 flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x132a/0x3b00 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917
 __mutex_lock_common kernel/locking/mutex.c:678 [inline]
 __mutex_lock+0x6c7/0xb90 kernel/locking/mutex.c:746
 device_lock include/linux/device.h:922 [inline]
 uevent_show+0x187/0x3b0 drivers/base/core.c:2730
 dev_attr_show+0x53/0xe0 drivers/base/core.c:2424
 sysfs_kf_seq_show+0x213/0x3e0 fs/sysfs/file.c:65
 seq_read_iter+0x506/0x12b0 fs/seq_file.c:230
 kernfs_fop_read_iter+0x422/0x5a0 fs/kernfs/file.c:279
 new_sync_read fs/read_write.c:489 [inline]
 vfs_read+0x8c8/0xc70 fs/read_write.c:570
 ksys_read+0x12a/0x240 fs/read_write.c:713
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feff3b25b6a
RSP: 002b:00007ffd7717a268 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000556a0c340a80 RCX: 00007feff3b25b6a
RDX: 0000000000001000 RSI: 0000556a0c383700 RDI: 0000000000000008
RBP: 0000556a0c340a80 R08: 0000000000000008 R09: 0000000000000000
R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000003fff R14: 00007ffd7717a748 R15: 000000000000000a
 </TASK>
INFO: task udevd:12575 is blocked on a mutex likely owned by task kworker/0:4:18790.
task:kworker/0:4     state:R  running task     stack:22920 pid:18790 tgid:18790 ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x132a/0x3b00 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff890c1a00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff890c1a00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff890c1a00 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6764
4 locks held by kworker/u8:6/313:
2 locks held by getty/2900:
 #0: ffff8881120ac0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc900000432f0 (
&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
5 locks held by kworker/1:4/5229:
 #0: ffff8881066b3d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
 #1: 
ffffc90001f8fd18 ((work_completion)(&hub->events)
){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
 #2: ffff88810bb3f198 (&dev->mutex
){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
){....}-{4:4}, at: hub_event+0x1be/0x5030 drivers/usb/core/hub.c:5863
 #3: ffff88810bb52508 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3220 [inline]
 #3: ffff88810bb52508 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5432 [inline]
 #3: ffff88810bb52508 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5675 [inline]
 #3: ffff88810bb52508 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5835 [inline]
 #3: ffff88810bb52508 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x29da/0x5030 drivers/usb/core/hub.c:5917
 #4: ffff88810971f368 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5433 [inline]
 #4: ffff88810971f368 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5675 [inline]
 #4: ffff88810971f368 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5835 [inline]
 #4: ffff88810971f368 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x2a00/0x5030 drivers/usb/core/hub.c:5917
4 locks held by udevd/12562:
 #0: ffff88811f842790 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12b0 fs/seq_file.c:182
 #1: ffff8881164e7088 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154
 #2: ffff88810971d008 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155
 #3: ffff88810bb3f198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
 #3: ffff88810bb3f198 (&dev->mutex){....}-{4:4}, at: uevent_show+0x187/0x3b0 drivers/base/core.c:2730
4 locks held by udevd/12575:
 #0: ffff88811a7f28b8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12b0 fs/seq_file.c:182
 #1: ffff8881118aa088 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154
 #2: ffff888114e3dd28 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155
 #3: ffff88811d4b4198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
 #3: ffff88811d4b4198 (&dev->mutex){....}-{4:4}, at: uevent_show+0x187/0x3b0 drivers/base/core.c:2730
4 locks held by udevd/12793:
 #0: ffff888113952c30 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12b0 fs/seq_file.c:182
 #1: ffff88811a07c888
 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154
 #2: ffff88810837ff08 (kn->active
#5
){++++}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155
 #3: ffff88810bb57198 (&dev->mutex){....}-{4:4}
, at: device_lock include/linux/device.h:922 [inline]
, at: uevent_show+0x187/0x3b0 drivers/base/core.c:2730
3 locks held by kworker/1:9/15368:
 #0: ffff8881066b3d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
 #1: ffffc9000e22fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
 #2: ffff88810bb57198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
 #2: ffff88810bb57198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x5030 drivers/usb/core/hub.c:5863
6 locks held by kworker/0:4/18790:
5 locks held by kworker/1:8/22559:
 #0: ffff8881066b3d48
 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
 #1: ffffc9000212fd18
 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
 #2: ffff88810bba7198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
 #2: ffff88810bba7198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x5030 drivers/usb/core/hub.c:5863
 #3: ffff88810bbba508
 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3220 [inline]
 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5432 [inline]
 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5675 [inline]
 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5835 [inline]
 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x29da/0x5030 drivers/usb/core/hub.c:5917
 #4: ffff888109724f68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5433 [inline]
 #4: ffff888109724f68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5675 [inline]
 #4: ffff888109724f68 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5835 [inline]
 #4: ffff888109724f68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x2a00/0x5030 drivers/usb/core/hub.c:5917
2 locks held by syz.9.4708/24581:

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.15.0-rc1-syzkaller-00082-gf41f7b3d9daf #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline]
 watchdog+0x11c4/0x15d0 kernel/hung_task.c:437
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: kworker/1:1 Not tainted 6.15.0-rc1-syzkaller-00082-gf41f7b3d9daf #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events legacy_dvb_usb_read_remote_control
RIP: 0010:number+0x676/0xc70 lib/vsprintf.c:521
Code: e8 0f 7b 5d fa 41 83 ed 01 31 ff 49 83 c4 01 44 89 ee e8 3d 76 5d fa 41 83 fd ff 75 a8 8b 04 24 c7 04 24 ff ff ff ff 48 01 c3 <e8> e5 7a 5d fa 44 0f b6 6c 24 35 31 ff 44 89 ee e8 b5 75 5d fa 45
RSP: 0018:ffffc900002871d8 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffc900002875df RCX: ffffffff871ecde9
RDX: ffff888104ee57c0 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000006 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000010 R11: 0000000000d1bed0 R12: 0000000000000010
R13: 0000000000000000 R14: ffffc900802875d7 R15: 0000000000000005
FS:  0000000000000000(0000) GS:ffff8882692d3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd77174d48 CR3: 0000000116844000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 vsnprintf+0x5e6/0x1160 lib/vsprintf.c:2816
 sprintf+0xcc/0x100 lib/vsprintf.c:3015
 print_time kernel/printk/printk.c:1381 [inline]
 info_print_prefix+0x25a/0x350 kernel/printk/printk.c:1407
 record_print_text+0x140/0x400 kernel/printk/printk.c:1456
 printk_get_next_message+0x2d1/0x6d0 kernel/printk/printk.c:3024
 console_emit_next_record kernel/printk/printk.c:3092 [inline]
 console_flush_all+0x6ea/0xc60 kernel/printk/printk.c:3226
 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
 console_unlock+0xd8/0x210 kernel/printk/printk.c:3325
 vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450
 _printk+0xc7/0x100 kernel/printk/printk.c:2475
 m920x_read drivers/media/usb/dvb-usb/m920x.c:40 [inline]
 m920x_rc_query+0x496/0x770 drivers/media/usb/dvb-usb/m920x.c:193
 legacy_dvb_usb_read_remote_control+0x109/0x4f0 drivers/media/usb/dvb-usb/dvb-usb-remote.c:123
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>