syzbot
INFO: task hung in osif_disconnect
Status:
upstream: reported on 2026/10/20 02:22
Reported-by: syzbot+53851a4c6a58ac13618b@syzkaller.appspotmail.com
First crash: 24d, last: 21d
Sample crash report:
INFO: task kworker/1:7:4395 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:7 state:D stack:21696 pid:4395 ppid:2 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2144
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x2c2/0x590 kernel/sched/completion.c:138
i2c_del_adapter+0x2d6/0x430 drivers/i2c/i2c-core-base.c:1849
osif_disconnect+0x42/0x80 drivers/i2c/busses/i2c-robotfuzz-osif.c:185
usb_unbind_interface+0x200/0x870 drivers/usb/core/driver.c:457
device_remove drivers/base/dd.c:549 [inline]
__device_release_driver drivers/base/dd.c:1279 [inline]
device_release_driver_internal+0x4cf/0x7c0 drivers/base/dd.c:1305
bus_remove_device+0x2dd/0x400 drivers/base/bus.c:531
device_del+0x63f/0xa80 drivers/base/core.c:3900
usb_disable_device+0x3e7/0x8a0 drivers/usb/core/message.c:1472
usb_disconnect+0x33c/0x8a0 drivers/usb/core/hub.c:2319
hub_port_connect drivers/usb/core/hub.c:5366 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5662 [inline]
port_event drivers/usb/core/hub.c:5822 [inline]
hub_event+0x1d27/0x5200 drivers/usb/core/hub.c:5904
process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8d92e230 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8d92ea50 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8d92d8a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8d92d8a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8d92d8a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6669
2 locks held by getty/4029:
#0: ffff888031549098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
5 locks held by kworker/1:7/4395:
#0: ffff888143eb2938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90004557d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffff888146312190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#2: ffff888146312190 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5200 drivers/usb/core/hub.c:5850
#3: ffff88802a7be190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#3: ffff88802a7be190 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0xf8/0x8a0 drivers/usb/core/hub.c:2310
#4: ffff888076b26118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#4: ffff888076b26118 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1099 [inline]
#4: ffff888076b26118 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb1/0x7c0 drivers/base/dd.c:1302
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xf0e/0xf50 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 22 Comm: kworker/1:0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Workqueue: events_power_efficient wg_ratelimiter_gc_entries
RIP: 0010:arch_irqs_disabled_flags arch/x86/include/asm/irqflags.h:125 [inline]
RIP: 0010:lock_acquire+0x187/0x4a0 kernel/locking/lockdep.c:5791
Code: 9c 8f 84 24 a0 00 00 00 4c 8b b4 24 a0 00 00 00 43 c6 44 3c 08 f8 fa 48 c7 c7 80 26 8c 8a e8 e0 fe cf 08 65 ff 05 19 79 9e 7e <45> 31 c9 41 f7 c6 00 02 00 00 41 0f 94 c1 48 8b 7c 24 18 8b 74 24
RSP: 0018:ffffc900001c7aa0 EFLAGS: 00000002
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 7003be27c59c1300
RDX: 0000000000000000 RSI: ffffffff8a8c2680 RDI: ffffffff8adf7160
RBP: ffffc900001c7bc0 R08: ffffffff8f00d22f R09: 1ffffffff1e01a45
R10: dffffc0000000000 R11: fffffbfff1e01a46 R12: 1ffff92000038f60
R13: 0000000000000001 R14: 0000000000000246 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b8d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9ecabf62f8 CR3: 0000000030c26000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
wg_ratelimiter_gc_entries+0x59/0x450 drivers/net/wireguard/ratelimiter.c:63
process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
* Struck through repros no longer work on HEAD.