INFO: task syz.0.472:7938 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.472 state:D stack:28856 pid:7938 tgid:7937 ppid:5817 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 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
comedi_open+0xe0/0x5a0 drivers/comedi/comedi_fops.c:2868
chrdev_open+0x234/0x6a0 fs/char_dev.c:414
do_dentry_open+0x982/0x1530 fs/open.c:965
vfs_open+0x82/0x3f0 fs/open.c:1097
do_open fs/namei.c:3975 [inline]
path_openat+0x1de4/0x2cb0 fs/namei.c:4134
do_filp_open+0x20b/0x470 fs/namei.c:4161
do_sys_openat2+0x11b/0x1d0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x174/0x210 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb3f3b8f749
RSP: 002b:00007fb3f4998038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fb3f3de5fa0 RCX: 00007fb3f3b8f749
RDX: 0000000000000400 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007fb3f3c13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb3f3de6038 R14: 00007fb3f3de5fa0 R15: 00007ffe5d744078
Showing all locks held in the system:
3 locks held by kworker/0:1/10:
#0: ffff88813ff11948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
#1: ffffc900000f7d00 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
#2: ffffffff8e3cfcf8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343
2 locks held by kworker/u8:1/13:
#0: ffff8880b843a398 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:646 [inline]
#0: ffff8880b843a398 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:631
#1: ffff8880b8524088 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:220 [inline]
#1: ffff8880b8524088 (psi_seq){-.-.}-{0:0}, at: __schedule+0x1861/0x5de0 kernel/sched/core.c:6923
1 lock held by khungtaskd/31:
#0: ffffffff8e3c4760 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e3c4760 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e3c4760 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
2 locks held by getty/5578:
#0: ffff8880363cd0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
3 locks held by syz.4.247/6964:
#0: ffff888079874dc8 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0x90 net/bluetooth/hci_core.c:499
#1: ffff8880798740b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x3ae/0x11d0 net/bluetooth/hci_sync.c:5296
#2: ffffffff8e3cfcf8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343
1 lock held by syz.1.405/7618:
1 lock held by syz.0.472/7938:
#0: ffff8880306770f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xe0/0x5a0 drivers/comedi/comedi_fops.c:2868
1 lock held by syz.6.804/9349:
#0: ffff8880306770f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xe0/0x5a0 drivers/comedi/comedi_fops.c:2868
3 locks held by syz-executor/9564:
#0: ffff8880206f8dc8 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0x90 net/bluetooth/hci_core.c:499
#1: ffff8880206f80b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x3ae/0x11d0 net/bluetooth/hci_sync.c:5296
#2: ffffffff9035bcc8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2119 [inline]
#2: ffffffff9035bcc8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x260 net/bluetooth/hci_conn.c:2614
4 locks held by syz.5.968/10002:
#0: ffff88806519cdc8 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0x90 net/bluetooth/hci_core.c:499
#1: ffff88806519c0b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x3ae/0x11d0 net/bluetooth/hci_sync.c:5296
#2: ffffffff9035bcc8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2119 [inline]
#2: ffffffff9035bcc8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x260 net/bluetooth/hci_conn.c:2614
#3: ffff888078650b38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x80/0x730 net/bluetooth/l2cap_core.c:1763
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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: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+0x675/0x7d0 arch/x86/kernel/process.c:158
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: 10006 Comm: syz.3.969 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:find_held_lock+0x75/0x80 kernel/locking/lockdep.c:5373
Code: 75 19 83 ed 01 48 83 eb 28 83 fd ff 74 0b 0f b6 43 49 32 43 21 a8 60 74 da 31 db 41 89 6d 00 48 89 d8 5b 5d 41 5c 41 5d 41 5e cc cc cc cc 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9001bcff818 EFLAGS: 00000002
RAX: ffff88804b9f5430 RBX: ffffffff9ad3d238 RCX: ffffc9001bcff82c
RDX: 0000000000000001 RSI: ffffffff9ad3d238 RDI: ffff88804b9f5430
RBP: 0000000000000282 R08: 0000000000000001 R09: fffff5200379fefe
R10: 0000000000000003 R11: 0000000000000001 R12: ffffffff84acca9f
R13: 0000000000000006 R14: ffff88804b9f4900 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888124a05000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000404000 CR3: 0000000066018000 CR4: 00000000003526f0
Call Trace:
__lock_release kernel/locking/lockdep.c:5535 [inline]
lock_release+0xe4/0x2f0 kernel/locking/lockdep.c:5889
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline]
_raw_spin_unlock_irqrestore+0x1a/0x80 kernel/locking/spinlock.c:194
__debug_check_no_obj_freed lib/debugobjects.c:1108 [inline]
debug_check_no_obj_freed+0x31f/0x600 lib/debugobjects.c:1129
remove_vm_area+0x1ae/0x3f0 mm/vmalloc.c:3297
vfree+0x90/0xb50 mm/vmalloc.c:3420
kcov_put kernel/kcov.c:439 [inline]
kcov_put kernel/kcov.c:435 [inline]
kcov_close+0x34/0x60 kernel/kcov.c:535
__fput+0x402/0xb70 fs/file_table.c:468
task_work_run+0x150/0x240 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x86f/0x2bf0 kernel/exit.c:966
do_group_exit+0xd3/0x2a0 kernel/exit.c:1107
get_signal+0x2671/0x26d0 kernel/signal.c:3034
arch_do_signal_or_restart+0x8f/0x7c0 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x85/0x130 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x426/0xfa0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f428558f749
Code: Unable to access opcode bytes at 0x7f428558f71f.
RSP: 002b:00007ffd696689f8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f42857e7da0 RCX: 00007f428558f749
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f42857e7da0 R08: 0000000000000220 R09: 0000001e69668cef
R10: 00000000003ffbb8 R11: 0000000000000246 R12: 00000000000541b9
R13: 00007f42857e6090 R14: ffffffffffffffff R15: 00007ffd69668b10
vkms_vblank_simulate: vblank timer overrun