INFO: task udevd:5231 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:5231 tgid:5231 ppid:2839 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+0x506/0x12b0 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: 0033:0x7f2946317b6a
RSP: 002b:00007ffd77bcdea8 EFLAGS: 00000246
ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000561372fbcbe0 RCX: 00007f2946317b6a
RDX: 0000000000001000 RSI: 0000561372fcd340 RDI: 0000000000000008
RBP: 0000561372fbcbe0 R08: 0000000000000008 R09: 0000000000000000
R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000003fff R14: 00007ffd77bce388 R15: 000000000000000a
INFO: task udevd:5231 is blocked on a mutex likely owned by task kworker/1:7:5959.
task:kworker/1:7 state:R running task stack:22776 pid:5959 tgid:5959 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x132a/0x3b00 kernel/sched/core.c:6767
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
5 locks held by kworker/u8:8/1496:
2 locks held by getty/2897:
#0: ffff8881121fc0a0 (&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/5231:
#0: ffff88811789e668 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12b0 fs/seq_file.c:182
#1:
ffff88810e3b8088
(&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154
#2: ffff88811392b2d8 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155
#3:
ffff888119a58198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
ffff888119a58198 (&dev->mutex){....}-{4:4}, at: uevent_show+0x187/0x3b0 drivers/base/core.c:2730
3 locks held by kworker/0:5/5278:
#0: ffff888100080d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
#1: ffffc900020afd18 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
#2: ffffffff890ccf38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336
6 locks held by kworker/0:7/5551:
4 locks held by udevd/5636:
#0: ffff88811a21ec30 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12b0 fs/seq_file.c:182
#1: ffff888112af7888 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154
#2: ffff88810fedda58 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155
#3: ffff88810b399198
(&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
(&dev->mutex){....}-{4:4}, at: uevent_show+0x187/0x3b0 drivers/base/core.c:2730
6 locks held by kworker/1:7/5959:
5 locks held by kworker/1:8/12563:
6 locks held by kworker/0:4/13580:
1 lock held by syz.1.3016/15420:
=============================================
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:
__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
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5199 Comm: kworker/1:2 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: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 81 9e 09 ff eb a0 e8 0a 9f 09
RSP: 0018:ffffc90001f5f6d8 EFLAGS: 00000002
RAX: 0000000000000032 RBX: 00000000000003f8 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: ffffffff82ce5ab5 RDI: ffffffff938b6820
RBP: ffffffff938b67e0 R08: 0000000000000001 R09: 000000000000001f
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000032 R14: ffffffff938b67e0 R15: ffffffff82ce5a50
FS: 0000000000000000(0000) GS:ffff8882692d3000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6efa8c0440 CR3: 0000000116ec6000 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:3306 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3378 [inline]
serial8250_console_write+0xfbc/0x1890 drivers/tty/serial/8250/8250_port.c:3456
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