syzbot


INFO: task hung in usbdev_open

Status: upstream: reported on 2025/12/23 17:09
Reported-by: syzbot+59ec26cedb2b42e7be25@syzkaller.appspotmail.com
First crash: 20d, last: 5d20h
Similar bugs (13)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in usbdev_open (3) 1 1 1114d 1114d 0/1 upstream: reported on 2022/12/25 16:08
upstream INFO: task hung in usbdev_open (2) usb 1 C error 2136 3h52m 1840d 0/29 upstream: reported C repro on 2020/12/29 11:48
linux-6.1 INFO: task hung in usbdev_open origin:lts-only 1 C done 3 960d 1018d 3/3 fixed on 2023/06/28 17:15
linux-4.19 INFO: task hung in usbdev_open (2) 1 2 1513d 1521d 0/1 auto-closed as invalid on 2022/03/21 09:54
linux-5.15 INFO: task hung in usbdev_open origin:lts-only 1 C error 19 478d 1017d 0/3 auto-obsoleted due to no activity on 2024/12/30 11:10
android-6-12 INFO: task hung in usbdev_open origin:upstream 1 syz 54 72d 203d 0/1 premoderation: reported syz repro on 2025/06/24 04:17
linux-6.1 INFO: task hung in usbdev_open (2) 1 1 764d 764d 0/3 auto-obsoleted due to no activity on 2024/03/20 05:29
linux-4.19 INFO: task hung in usbdev_open 1 6 1813d 1900d 0/1 auto-closed as invalid on 2021/05/25 14:21
linux-4.14 INFO: task hung in usbdev_open 1 7 1773d 1911d 0/1 auto-closed as invalid on 2021/07/05 05:59
upstream INFO: task hung in usbdev_open usb 1 2 2302d 2302d 0/29 auto-closed as invalid on 2019/12/23 20:14
linux-6.1 INFO: task hung in usbdev_open (3) 1 1 653d 653d 0/3 auto-obsoleted due to no activity on 2024/07/09 03:03
linux-4.14 INFO: task hung in usbdev_open (2) 1 1 1065d 1065d 0/1 upstream: reported on 2023/02/13 07:50
upstream INFO: task can't die in usbdev_open usb 1 4 1806d 1919d 0/29 auto-closed as invalid on 2021/04/02 18:49

Sample crash report:
INFO: task syz.5.1939:16449 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.1939      state:D stack:26224 pid:16449 ppid:16154  flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
 device_lock include/linux/device.h:995 [inline]
 usbdev_open+0x16f/0x760 drivers/usb/core/devio.c:1051
 chrdev_open+0x59e/0x670 fs/char_dev.c:414
 do_dentry_open+0x8c6/0x1500 fs/open.c:929
 do_open fs/namei.c:3640 [inline]
 path_openat+0x274b/0x3190 fs/namei.c:3797
 do_filp_open+0x1c5/0x3d0 fs/namei.c:3824
 do_sys_openat2+0x12c/0x1c0 fs/open.c:1421
 do_sys_open fs/open.c:1436 [inline]
 __do_sys_openat fs/open.c:1452 [inline]
 __se_sys_openat fs/open.c:1447 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1447
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f09d0b8df90
RSP: 002b:00007f09d19c8b70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f09d0b8df90
RDX: 0000000000000002 RSI: 00007f09d19c8c10 RDI: 00000000ffffff9c
RBP: 00007f09d19c8c10 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: cccccccccccccccd
R13: 00007f09d0de6038 R14: 00007f09d0de5fa0 R15: 00007ffcc0cf44d8
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
 #0: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline]
 #0: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x360/0x830 kernel/rcu/tree_exp.h:1004
1 lock held by khungtaskd/29:
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
2 locks held by getty/5524:
 #0: ffff888031ada0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
2 locks held by kworker/0:3/5794:
 #0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90004a1fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90004a1fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
5 locks held by kworker/0:5/5817:
 #0: ffff88814667f138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff88814667f138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90004c2fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90004c2fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffff8880255a8190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline]
 #2: ffff8880255a8190 (&dev->mutex){....}-{3:3}, at: hub_event+0x185/0x49c0 drivers/usb/core/hub.c:5861
 #3: ffff888079afb190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline]
 #3: ffff888079afb190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x400 drivers/base/dd.c:1005
 #4: ffff88805fbea160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline]
 #4: ffff88805fbea160 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x400 drivers/base/dd.c:1005
5 locks held by kworker/0:6/5831:
 #0: ffff88814667f138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff88814667f138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90004d3fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90004d3fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffff888142f84190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline]
 #2: ffff888142f84190 (&dev->mutex){....}-{3:3}, at: hub_event+0x185/0x49c0 drivers/usb/core/hub.c:5861
 #3: ffff888141f7e508 (&port_dev->status_lock){+.+.}-{3:3}, at: usb_lock_port drivers/usb/core/hub.c:3215 [inline]
 #3: ffff888141f7e508 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5426 [inline]
 #3: ffff888141f7e508 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5669 [inline]
 #3: ffff888141f7e508 (&port_dev->status_lock){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5833 [inline]
 #3: ffff888141f7e508 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_event+0x21ab/0x49c0 drivers/usb/core/hub.c:5915
 #4: ffff888142f0df68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5427 [inline]
 #4: ffff888142f0df68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5669 [inline]
 #4: ffff888142f0df68 (hcd->address0_mutex){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5833 [inline]
 #4: ffff888142f0df68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_event+0x21d3/0x49c0 drivers/usb/core/hub.c:5915
1 lock held by syz.5.1939/16449:
 #0: ffff8880255a8190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline]
 #0: ffff8880255a8190 (&dev->mutex){....}-{3:3}, at: usbdev_open+0x16f/0x760 drivers/usb/core/devio.c:1051
3 locks held by kworker/1:12/16530:
 #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90004c17d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90004c17d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffff8880268ee240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x26c/0x3170 drivers/net/netdevsim/fib.c:1491
2 locks held by kworker/u4:12/17420:
2 locks held by syz.6.2406/18418:
 #0: ffff888031597a20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
 #0: ffff888031597a20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:658 [inline]
 #0: ffff888031597a20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x9b/0x230 net/socket.c:1421
 #1: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline]
 #1: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x360/0x830 kernel/rcu/tree_exp.h:1004
3 locks held by kvm-nx-lpage-re/18425:
 #0: ffffffff8cd59988 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:369 [inline]
 #0: ffffffff8cd59988 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_attach_task_all+0x26/0xe0 kernel/cgroup/cgroup-v1.c:61
 #1: ffffffff8cbcb210 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock+0x11/0x30 kernel/cgroup/cgroup.c:2414
 #2: ffffffff8cd59b70 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_task_all+0x30/0xe0 kernel/cgroup/cgroup-v1.c:62

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

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf41/0xf80 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6428 Comm: kworker/u4:9 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:__sanitizer_cov_trace_switch+0x81/0x120 kernel/kcov.c:349
Code: 00 00 00 b9 01 00 00 00 48 85 c0 0f 84 ae 00 00 00 41 57 41 56 41 54 53 48 8b 54 24 20 65 4c 8b 05 c4 1f 7e 7e 45 31 c9 eb 08 <49> ff c1 4c 39 c8 74 77 4e 8b 54 ce 10 65 44 8b 1d b2 1f 7e 7e 41
RSP: 0018:ffffc9000cb571f8 EFLAGS: 00000293
RAX: 000000000000002b RBX: 000000000000000a RCX: 0000000000000001
RDX: ffffffff89e9b59d RSI: ffffffff8e23bb00 RDI: 0000000000000001
RBP: ffffc9000cb575f0 R08: ffff88802d5d3c00 R09: 0000000000000023
R10: 00000000000000c7 R11: 0000000000000000 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff88803fea4d7c R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3618b7 CR3: 000000002f1b7000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 _ieee802_11_parse_elems_full+0xc1d/0x3920 net/mac80211/util.c:1106
 ieee802_11_parse_elems_full+0xd4d/0x2080 net/mac80211/util.c:1635
 ieee802_11_parse_elems_crc net/mac80211/ieee80211_i.h:2337 [inline]
 ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2344 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1609 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x49b/0x2ac0 net/mac80211/ibss.c:1642
 ieee80211_iface_process_skb net/mac80211/iface.c:1651 [inline]
 ieee80211_iface_work+0x717/0xc70 net/mac80211/iface.c:1705
 cfg80211_wiphy_work+0x225/0x260 net/wireless/core.c:437
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/07 12:15 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in usbdev_open
2025/12/29 17:37 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in usbdev_open
2025/12/23 17:08 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in usbdev_open
* Struck through repros no longer work on HEAD.