INFO: task udevd:5577 blocked for more than 143 seconds.
Not tainted 6.15.0-rc1-syzkaller-00097-g3baea29dc0a7 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:24536 pid:5577 tgid:5577 ppid:2842 task_flags:0x400140 flags:0x00000002
Call Trace:
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+0x506/0x12c0 fs/seq_file.c:230
kernfs_fop_read_iter+0x40f/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: 0033:0x7f7153768b6a
RSP: 002b:00007ffcc8a1ae48 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000562ded69e7c0 RCX: 00007f7153768b6a
RDX: 0000000000001000 RSI: 0000562ded719cc0 RDI: 0000000000000008
RBP: 0000562ded69e7c0 R08: 0000000000000008 R09: 0000000000000010
R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000003fff R14: 00007ffcc8a1b328 R15: 000000000000000a
Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0:
ffffffff890c2840
(rcu_read_lock
){....}-{1:3}
, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6764
2 locks held by getty/2900:
#0: ffff8881124560a0
(&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
4 locks held by udevd/5233:
4 locks held by udevd/5577:
#0: ffff888111f299e0
(
&p->lock){+.+.}-{4:4}
, at: seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182
#1: ffff88811de5e088
(&of->mutex#2){+.+.}-{4:4}
, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154
#2: ffff8881188cdb48
(
kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155
#3: ffff888120df1198
(&dev->mutex
){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
){....}-{4:4}, at: uevent_show+0x187/0x3b0 drivers/base/core.c:2730
5 locks held by kworker/1:6/5760:
#0: ffff888106ed6548
(
(wq_completion)usb_hub_wq
){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
#1: ffffc90012a4fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}
, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
#2:
ffff88810b326198
(
&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: ffff88811c300198 (&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:922 [inline]
, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1005
#4: ffff88812e856160
(
&dev->mutex
){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1005
8 locks held by kworker/0:7/8512:
6 locks held by kworker/1:7/10470:
6 locks held by kworker/0:3/12864:
#0: ffff888106ed6548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}
, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
#1:
ffffc900098cfd18
(
(work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
#2: ffff88810b3b6198
(&dev->mutex){....}-{4:4}
, at: device_lock include/linux/device.h:922 [inline]
, at: hub_event+0x1be/0x5030 drivers/usb/core/hub.c:5863
#3: ffff88810b3c9508
(&port_dev->status_lock
){+.+.}-{4:4}
, at: usb_lock_port drivers/usb/core/hub.c:3220 [inline]
, at: hub_port_connect drivers/usb/core/hub.c:5432 [inline]
, at: hub_port_connect_change drivers/usb/core/hub.c:5675 [inline]
, at: port_event drivers/usb/core/hub.c:5835 [inline]
, at: hub_event+0x29da/0x5030 drivers/usb/core/hub.c:5917
#4: ffff888108327168 (hcd->address0_mutex
){+.+.}-{4:4}
, at: hub_port_connect drivers/usb/core/hub.c:5433 [inline]
, at: hub_port_connect_change drivers/usb/core/hub.c:5675 [inline]
, at: port_event drivers/usb/core/hub.c:5835 [inline]
, at: hub_event+0x2a00/0x5030 drivers/usb/core/hub.c:5917
#5: ffffffff89beeb30
(ehci_cf_port_reset_rwsem
){.+.+}-{4:4}, at: hub_port_reset+0x1a1/0x1e00 drivers/usb/core/hub.c:3035
4 locks held by kworker/0:9/13773:
2 locks held by syz.0.3950/21430:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.15.0-rc1-syzkaller-00097-g3baea29dc0a7 #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
__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+0xf70/0x12c0 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
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 1117 Comm: kworker/0:2 Not tainted 6.15.0-rc1-syzkaller-00097-g3baea29dc0a7 #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:io_serial_out+0x8f/0xb0 drivers/tty/serial/8250/8250_port.c:416
Code: 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1c 66 03 5d 40 44 89 e8 89 da ee <5b> 5d 41 5c 41 5d c3 cc cc cc cc e8 21 a1 09 ff eb a0 e8 aa a1 09
RSP: 0018:ffffc90001d6f6b8 EFLAGS: 00000006
RAX: 0000000000000000 RBX: 00000000000003f9 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: ffffffff82ce7b05 RDI: ffffffff938c2820
RBP: ffffffff938c27e0 R08: 0000000000000001 R09: 000000000000001f
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff938c27e0 R15: ffffffff938c2aa0
FS: 0000000000000000(0000) GS:ffff8882691c7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c379273 CR3: 00000001161b6000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
serial_out drivers/tty/serial/8250/8250.h:142 [inline]
serial8250_clear_IER+0x9b/0xc0 drivers/tty/serial/8250/8250_port.c:717
serial8250_console_write+0x255/0x1890 drivers/tty/serial/8250/8250_port.c:3421
console_emit_next_record kernel/printk/printk.c:3138 [inline]
console_flush_all+0x7fe/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