INFO: task udevd:9335 blocked for more than 143 seconds.
Not tainted 6.14.0-rc6-syzkaller-ged492c95f13a #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D
stack:23808 pid:9335 tgid:9335 ppid:2847 task_flags:0x400140 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5378 [inline]
__schedule+0x113d/0x35d0 kernel/sched/core.c:6765
__schedule_loop kernel/sched/core.c:6842 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6857
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6914
__mutex_lock_common kernel/locking/mutex.c:662 [inline]
__mutex_lock+0x6bd/0xb10 kernel/locking/mutex.c:730
device_lock include/linux/device.h:1030 [inline]
uevent_show+0x188/0x3b0 drivers/base/core.c:2730
dev_attr_show+0x53/0xe0 drivers/base/core.c:2424
sysfs_kf_seq_show+0x23e/0x410 fs/sysfs/file.c:59
seq_read_iter+0x4f4/0x12b0 fs/seq_file.c:230
kernfs_fop_read_iter+0x414/0x580 fs/kernfs/file.c:279
new_sync_read fs/read_write.c:484 [inline]
vfs_read+0x886/0xbf0 fs/read_write.c:565
ksys_read+0x12b/0x250 fs/read_write.c:708
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f29483ceb6a
RSP: 002b:00007fff4aa4afd8 EFLAGS: 00000246
ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000563b982dbc40 RCX: 00007f29483ceb6a
RDX: 0000000000001000 RSI: 0000563b9835bb40 RDI: 0000000000000008
RBP: 0000563b982dbc40 R08: 0000000000000008 R09: 0000000000000000
R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000003fff R14: 00007fff4aa4b4b8 R15: 000000000000000a
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff88ebe8c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
#0: ffffffff88ebe8c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff88ebe8c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6746
6 locks held by kworker/1:1/42:
4 locks held by kworker/0:2/2807:
2 locks held by getty/2905:
#0: ffff888108afe0a0 (&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+0xfba/0x1480 drivers/tty/n_tty.c:2211
4 locks held by udevd/9335:
#0: ffff88811e6332f0 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xd8/0x12b0 fs/seq_file.c:182
#1: ffff888119d1e088 (&of->mutex#2
){+.+.}-{4:4}
, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154
#2: ffff88811d400008 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155
#3: ffff8881072de198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1030 [inline]
#3: ffff8881072de198 (&dev->mutex){....}-{4:4}, at: uevent_show+0x188/0x3b0 drivers/base/core.c:2730
4 locks held by udevd/10233:
#0:
ffff888119a6d9e0 (
&p->lock
){+.+.}-{4:4}, at: seq_read_iter+0xd8/0x12b0 fs/seq_file.c:182
#1: ffff88811dc0f088 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154
#2: ffff88810db140f8 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155
#3: ffff88811bd46198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1030 [inline]
#3: ffff88811bd46198 (&dev->mutex){....}-{4:4}, at: uevent_show+0x188/0x3b0 drivers/base/core.c:2730
5 locks held by kworker/1:6/11830:
#0: ffff8881062c7948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3213
#1:
ffffc90001d2fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3214
#2: ffff88810bbec198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1030 [inline]
#2: ffff88810bbec198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x4f40 drivers/usb/core/hub.c:5859
#3: ffff88811bd46198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1030 [inline]
#3: ffff88811bd46198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7f/0x4b0 drivers/base/dd.c:1005
#4: ffff88811a6f9160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1030 [inline]
#4: ffff88811a6f9160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7f/0x4b0 drivers/base/dd.c:1005
4 locks held by kworker/u8:1/12478:
#0: ffff888100ac3948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3213
#1: ffffc90011dbfd18 (
net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3214
#2: ffffffff8a19a310 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xca/0xb30 net/core/net_namespace.c:606
#3: ffffffff8a1aff68 (rtnl_mutex){+.+.}-{4:4}, at: cleanup_net+0x512/0xb30 net/core/net_namespace.c:642
2 locks held by kworker/0:0/15575:
#0: ffff888100080d48 (
(wq_completion)events
){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3213
#1: ffffc9000189fd18 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3214
3 locks held by kworker/1:10/16228:
1 lock held by syz.7.3753/22150:
#0: ffffffff88ec9d38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a4/0x3b0 kernel/rcu/tree_exp.h:334
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.14.0-rc6-syzkaller-ged492c95f13a #0
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:162 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline]
watchdog+0xf62/0x12b0 kernel/hung_task.c:399
kthread+0x3af/0x750 kernel/kthread.c:464
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 2807 Comm: kworker/0:2 Not tainted 6.14.0-rc6-syzkaller-ged492c95f13a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events 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 d1 67 0c ff eb a0 e8 5a 68 0c
RSP: 0000:ffffc900050ef778 EFLAGS: 00000002
RAX: 0000000000000035 RBX: 00000000000003f8 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: ffffffff82c90465 RDI: ffffffff936912a0
RBP: ffffffff93691260 R08: 0000000000000001 R09: 000000000000001f
R10: 0000000000000000 R11: 0000000000000006 R12: 0000000000000000
R13: 0000000000000035 R14: ffffffff93691260 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881f5800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feb4c29c440 CR3: 000000011674c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
serial_port_out include/linux/serial_core.h:796 [inline]
serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3315 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3387 [inline]
serial8250_console_write+0xfb1/0x1870 drivers/tty/serial/8250/8250_port.c:3465
console_emit_next_record kernel/printk/printk.c:3122 [inline]
console_flush_all+0x800/0xc60 kernel/printk/printk.c:3210
__console_flush_and_unlock kernel/printk/printk.c:3269 [inline]
console_unlock+0xd9/0x210 kernel/printk/printk.c:3309
vprintk_emit+0x424/0x6f0 kernel/printk/printk.c:2432
_printk+0xc8/0x100 kernel/printk/printk.c:2457
m920x_read drivers/media/usb/dvb-usb/m920x.c:40 [inline]
m920x_rc_core_query+0x2d7/0x500 drivers/media/usb/dvb-usb/m920x.c:229
dvb_usb_read_remote_control+0xda/0x1c0 drivers/media/usb/dvb-usb/dvb-usb-remote.c:261
process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238
process_scheduled_works kernel/workqueue.c:3319 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400
kthread+0x3af/0x750 kernel/kthread.c:464
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244