INFO: task syz.9.5315:25830 blocked for more than 143 seconds.
Not tainted 6.16.0-next-20250808-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.5315 state:D stack:27288 pid:25830 tgid:25828 ppid:23927 task_flags:0x400140 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x7e6/0x1360 kernel/locking/mutex.c:760
comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2863
chrdev_open+0x4c9/0x5e0 fs/char_dev.c:414
do_dentry_open+0x950/0x13f0 fs/open.c:965
vfs_open+0x3b/0x340 fs/open.c:1095
do_open fs/namei.c:3887 [inline]
path_openat+0x2ee5/0x3830 fs/namei.c:4046
do_filp_open+0x1fa/0x410 fs/namei.c:4073
do_sys_openat2+0x121/0x1c0 fs/open.c:1435
do_sys_open fs/open.c:1450 [inline]
__do_sys_openat fs/open.c:1466 [inline]
__se_sys_openat fs/open.c:1461 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1461
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5e06f8ebe9
RSP: 002b:00007f5e07e2b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f5e071b6090 RCX: 00007f5e06f8ebe9
RDX: 0000000000002000 RSI: 0000200000000040 RDI: 00000000ffffff9c
RBP: 00007f5e07011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5e071b6128 R14: 00007f5e071b6090 R15: 00007ffec7a9e608
Showing all locks held in the system:
5 locks held by kworker/0:0/9:
1 lock held by khungtaskd/31:
#0: ffffffff8e539ee0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e539ee0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e539ee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by udevd/5236:
2 locks held by getty/5627:
#0: ffff888033a160a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
6 locks held by kworker/1:7/18960:
#0: ffff888022285548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff888022285548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc9000b6c7bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc9000b6c7bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff888144389198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#2: ffff888144389198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20 drivers/usb/core/hub.c:5898
#3: ffff888028565518 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3251 [inline]
#3: ffff888028565518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5463 [inline]
#3: ffff888028565518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5706 [inline]
#3: ffff888028565518 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5870 [inline]
#3: ffff888028565518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x21b8/0x4a20 drivers/usb/core/hub.c:5952
#4: ffff888027b6be68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline]
#4: ffff888027b6be68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5706 [inline]
#4: ffff888027b6be68 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5870 [inline]
#4: ffff888027b6be68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21e5/0x4a20 drivers/usb/core/hub.c:5952
#5: ffffffff8f1f44d0 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x163/0x1750 drivers/usb/core/hub.c:3066
2 locks held by syz.6.5308/25788:
1 lock held by syz.9.5315/25830:
#0: ffff88814c55b8f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2863
1 lock held by syz.5.5575/27549:
#0: ffff88814c55b8f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2863
1 lock held by rm/28277:
#0: ffff8880b8639f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:636
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-next-20250808-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/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+0xf60/0xfa0 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5853 Comm: syz-executor Not tainted 6.16.0-next-20250808-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:sock_read_iter+0x91/0x2f0 net/socket.c:1142
Code: f1 f1 f1 41 c7 44 1f 11 f3 f3 f3 f3 66 41 c7 44 1f 15 f3 f3 41 c6 44 1f 17 f3 e8 2a ef 5e f8 4c 89 e0 48 c1 e8 03 80 3c 18 00 <74> 08 4c 89 e7 e8 55 5b c2 f8 48 8d 5c 24 40 4d 8b 2c 24 49 8d 7d
RSP: 0018:ffffc9000404fb60 EFLAGS: 00000246
RAX: 1ffff92000809fa4 RBX: dffffc0000000000 RCX: ffff888031a35a00
RDX: 0000000000000000 RSI: ffffc9000404fd70 RDI: ffffc9000404fd20
RBP: ffffc9000404fc90 R08: ffffc9000404fd7f R09: 0000000000000000
R10: ffffc9000404fd70 R11: ffffffff89611410 R12: ffffc9000404fd20
R13: 0000000000000000 R14: 1ffff92000809fa0 R15: 1ffff92000809f70
FS: 000055555f52b500(0000) GS:ffff8881257db000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffda7aa4ca8 CR3: 00000000779d2000 CR4: 00000000003526f0
DR0: 000000000000000a DR1: 0000000000000002 DR2: 0000000000000003
DR3: 0000000080000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
new_sync_read fs/read_write.c:491 [inline]
vfs_read+0x55a/0xa30 fs/read_write.c:572
ksys_read+0x145/0x250 fs/read_write.c:715
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa53f38d5bd
Code: a8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb b5 e8 a8 48 00 00 0f 1f 84 00 00 00 00 00 80 3d a1 af 1f 00 00 74 17 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 5b c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec
RSP: 002b:00007fffcd561438 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa53f38d5bd
RDX: 0000000000000004 RSI: 00007fffcd56144c RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000031ffd875 R09: 7fffffffffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffcd561860
R13: 0000000000000004 R14: 00007fffcd56144c R15: 00007fffcd5614e0