syzbot


INFO: task hung in usb_remote_wakeup (7)

Status: auto-obsoleted due to no activity on 2026/01/19 09:40
Subsystems: usb
[Documentation on labels]
First crash: 162d, last: 94d
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in usb_remote_wakeup 1 1 1872d 1872d 0/1 auto-closed as invalid on 2021/04/07 18:31
upstream INFO: task hung in usb_remote_wakeup (2) usb 1 syz inconclusive done 9 1617d 1816d 20/29 fixed on 2021/11/10 00:50
upstream INFO: task hung in usb_remote_wakeup (3) usb 1 1 1430d 1430d 0/29 auto-closed as invalid on 2022/05/24 13:32
upstream INFO: task hung in usb_remote_wakeup (5) usb 1 1 989d 989d 0/29 auto-obsoleted due to no activity on 2023/08/08 04:40
upstream INFO: task hung in usb_remote_wakeup usb 1 7 2281d 2467d 0/29 auto-closed as invalid on 2020/01/24 14:16
upstream INFO: task hung in usb_remote_wakeup (4) usb 1 2 1170d 1220d 0/29 auto-obsoleted due to no activity on 2023/02/10 23:06
upstream INFO: task hung in usb_remote_wakeup (6) usb 1 1 477d 477d 0/29 auto-obsoleted due to no activity on 2025/01/01 01:43
linux-4.14 INFO: task hung in usb_remote_wakeup 1 1 1932d 1932d 0/1 auto-closed as invalid on 2021/02/06 13:01

Sample crash report:
INFO: task kworker/1:0:23 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:0     state:D
 stack:21736 pid:23    tgid:23    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: pm hcd_resume_work

Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x12fc/0x3b80 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7026
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
 __mutex_lock_common kernel/locking/mutex.c:676 [inline]
 __mutex_lock+0x818/0x1060 kernel/locking/mutex.c:760
 device_lock include/linux/device.h:914 [inline]
 usb_remote_wakeup+0x21/0xe0 drivers/usb/core/hub.c:3880
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x56d/0x700 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/1:0/23:
 #0: ffff888100edc948 ((wq_completion)pm){+.+.}-{0:0}
, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: ffffc9000018fd10 ((work_completion)(&hcd->wakeup_work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: ffff88810b778198 (&dev->mutex
){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
){....}-{4:4}, at: usb_remote_wakeup+0x21/0xe0 drivers/usb/core/hub.c:3880
1 lock held by khungtaskd/30:
 #0: ffffffff894c89e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff894c89e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff894c89e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
6 locks held by kworker/1:1/38:
5 locks held by kworker/0:2/2517:
 #0: ffff888106a94548
 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: ffffc900035bfd10 ((work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: 
ffff88810b318198
 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 (&dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5893
 #3: ffff88810b31b510 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3246 [inline]
 #3: ffff88810b31b510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5458 [inline]
 #3: ffff88810b31b510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5701 [inline]
 #3: ffff88810b31b510 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5865 [inline]
 #3: ffff88810b31b510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x2a18/0x5060 drivers/usb/core/hub.c:5947
 #4: ffff888109fb8068 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5459 [inline]
 #4: ffff888109fb8068 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5701 [inline]
 #4: ffff888109fb8068 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5865 [inline]
 #4: ffff888109fb8068 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x2a3e/0x5060 drivers/usb/core/hub.c:5947
2 locks held by getty/2920:
 #0: ffff88811234c0a0 (&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/5192:
 #0: ffff888134b961c8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12d0 fs/seq_file.c:182
 #1: ffff88811b86e888 (&of->mutex
#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
 #2: ffff8881354eef08 (kn->active#9
){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173
 #3: ffff888113dca198 (&dev->mutex
){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:919 [inline]
){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
4 locks held by udevd/5224:
 #0: 
ffff8881368aee80 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12d0 fs/seq_file.c:182
 #1: ffff888115431488 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
 #2: ffff88811e47b698 (kn->active#9){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff88811e47b698 (kn->active#9){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173
 #3: ffff88811d4a1198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:919 [inline]
 #3: ffff88811d4a1198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
5 locks held by kworker/0:3/5226:
 #0: ffff888106a94548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: ffffc9000217fd10 ((work_completion)(&hub->events)
){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: ffff88810b700198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #2: ffff88810b700198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5893
 #3: ffff888101feb198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #3: ffff888101feb198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
 #4: ffff88811039f160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #4: ffff88811039f160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
6 locks held by kworker/1:7/6586:
4 locks held by udevd/8395:
 #0: ffff888134476b08 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12d0 fs/seq_file.c:182
 #1: ffff88810ffe1488 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
 #2: ffff88813381b2d8 (kn->active#17){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff88813381b2d8 (kn->active#17){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173
 #3: ffff888101feb198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:919 [inline]
 #3: ffff888101feb198 (&dev->mutex){....}-{4:4}, at: serial_show+0x26/0xa0 drivers/usb/core/sysfs.c:143
5 locks held by kworker/u8:2/15965:
 #0: ffff888100ac4948 ((wq_completion)netns
){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: 
ffffc9001638fd10 (net_cleanup_work){+.+.}-{0:0}
, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: ffffffff8a82e1f0 (pernet_ops_rwsem
){++++}-{4:4}, at: cleanup_net+0xad/0x8b0 net/core/net_namespace.c:669
 #3: ffffffff8a844548 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0x8b/0xaf0 net/core/dev.c:12807
 #4: ffffffff894d3f78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
 watchdog+0xf3f/0x1170 kernel/hung_task.c:495
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x56d/0x700 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: events legacy_dvb_usb_read_remote_control
RIP: 0010:io_serial_in+0x87/0xb0 drivers/tty/serial/8250/8250_port.c:401
Code: 2d 99 fe 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 1a 66 03 5d 40 89 da ec <5b> 0f b6 c0 5d 41 5c c3 cc cc cc cc e8 d8 60 f9 fe eb a2 e8 61 61
RSP: 0018:ffffc9000009f6d8 EFLAGS: 00000006
RAX: dffffc0000000005 RBX: 00000000000003f9 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: ffffffff82e57c50 RDI: ffffffff93e12760
RBP: ffffffff93e12720 R08: 0000000000000001 R09: 000000000000001f
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: ffffffff93e12770 R14: ffffffff93e12720 R15: ffffffff93e129e0
FS:  0000000000000000(0000) GS:ffff888268a6b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc1974c3e9c CR3: 0000000116bd6000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 serial_port_in include/linux/serial_core.h:806 [inline]
 serial8250_console_write+0x249/0x1890 drivers/tty/serial/8250/8250_port.c:3306
 console_emit_next_record kernel/printk/printk.c:3111 [inline]
 console_flush_all+0x801/0xc60 kernel/printk/printk.c:3199
 __console_flush_and_unlock kernel/printk/printk.c:3258 [inline]
 console_unlock+0xd8/0x210 kernel/printk/printk.c:3298
 vprintk_emit+0x3d7/0x680 kernel/printk/printk.c:2423
 _printk+0xc7/0x100 kernel/printk/printk.c:2448
 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+0x10c/0x4f0 drivers/media/usb/dvb-usb/dvb-usb-remote.c:123
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x56d/0x700 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/21 09:30 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 877c80dfbf78 9832ed61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in usb_remote_wakeup
2025/08/14 16:36 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing c0485e864a2e 5d8c2ac2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in usb_remote_wakeup
* Struck through repros no longer work on HEAD.