INFO: task syz.1.18:4522 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.18 state:D stack:26688 pid:4522 ppid:4397 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
chrdev_open+0x597/0x670 fs/char_dev.c:414
do_dentry_open+0x7e9/0x10d0 fs/open.c:882
do_open fs/namei.c:3634 [inline]
path_openat+0x25c6/0x2e70 fs/namei.c:3791
do_filp_open+0x1c1/0x3c0 fs/namei.c:3818
do_sys_openat2+0x142/0x490 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1347
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fbc42b8f749
RSP: 002b:00007ffc791e6048 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fbc42de5fa0 RCX: 00007fbc42b8f749
RDX: 0000000000000400 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007fbc42c13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbc42de5fa0 R14: 00007fbc42de5fa0 R15: 0000000000000004
INFO: task syz.0.17:4523 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17 state:D stack:26688 pid:4523 ppid:4396 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
chrdev_open+0x597/0x670 fs/char_dev.c:414
do_dentry_open+0x7e9/0x10d0 fs/open.c:882
do_open fs/namei.c:3634 [inline]
path_openat+0x25c6/0x2e70 fs/namei.c:3791
do_filp_open+0x1c1/0x3c0 fs/namei.c:3818
do_sys_openat2+0x142/0x490 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1347
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f396cb8f749
RSP: 002b:00007ffd493b0ad8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f396cde5fa0 RCX: 00007f396cb8f749
RDX: 0000000000000400 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007f396cc13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f396cde5fa0 R14: 00007f396cde5fa0 R15: 0000000000000004
INFO: task syz.4.21:4526 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.21 state:D stack:26688 pid:4526 ppid:4408 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
chrdev_open+0x597/0x670 fs/char_dev.c:414
do_dentry_open+0x7e9/0x10d0 fs/open.c:882
do_open fs/namei.c:3634 [inline]
path_openat+0x25c6/0x2e70 fs/namei.c:3791
do_filp_open+0x1c1/0x3c0 fs/namei.c:3818
do_sys_openat2+0x142/0x490 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1347
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f2b1f18f749
RSP: 002b:00007ffc3604f048 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f2b1f3e5fa0 RCX: 00007f2b1f18f749
RDX: 0000000000000400 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007f2b1f213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2b1f3e5fa0 R14: 00007f2b1f3e5fa0 R15: 0000000000000004
INFO: task syz.2.19:4529 blocked for more than 145 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.19 state:D stack:26688 pid:4529 ppid:4398 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
chrdev_open+0x597/0x670 fs/char_dev.c:414
do_dentry_open+0x7e9/0x10d0 fs/open.c:882
do_open fs/namei.c:3634 [inline]
path_openat+0x25c6/0x2e70 fs/namei.c:3791
do_filp_open+0x1c1/0x3c0 fs/namei.c:3818
do_sys_openat2+0x142/0x490 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1347
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f466d78f749
RSP: 002b:00007fff8a508e78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f466d9e5fa0 RCX: 00007f466d78f749
RDX: 0000000000000400 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007f466d813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f466d9e5fa0 R14: 00007f466d9e5fa0 R15: 0000000000000004
Showing all locks held in the system:
3 locks held by kworker/u4:0/9:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8c92bab0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8c92c2d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/27:
#0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
3 locks held by kworker/0:2/951:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc900049d7d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffff88804a3d9240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x26b/0x32b0 drivers/net/netdevsim/fib.c:1491
2 locks held by getty/4027:
#0: ffff88814d59e098 (&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+0x41b/0x1380 drivers/tty/n_tty.c:2198
2 locks held by syz.3.20/4515:
1 lock held by syz.1.18/4522:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.0.17/4523:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.4.21/4526:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.2.19/4529:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.5.22/4643:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.6.23/4657:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.7.24/4661:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.8.25/4662:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.9.26/4663:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.3.27/4717:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.1.28/4759:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.0.29/4761:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.2.31/4764:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.4.30/4778:
#0: ffff88802e8990f8
(&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.5.32/4801:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.7.34/4906:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.6.33/4913:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.9.35/4914:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.8.36/4921:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.3.37/4927:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.0.38/4986:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.2.40/5035:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.1.39/5037:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
1 lock held by syz.4.41/5044:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
3 locks held by syz-executor/5046:
1 lock held by syz.5.42/5056:
#0: ffff88802e8990f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xbc/0x580 drivers/comedi/comedi_fops.c:2811
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3f4/0x470 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+0xeee/0xf30 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4515 Comm: syz.3.20 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:multiq3_encoder_reset drivers/comedi/drivers/multiq3.c:227 [inline]
RIP: 0010:multiq3_attach+0x63d/0x940 drivers/comedi/drivers/multiq3.c:316
Code: 00 74 08 48 89 df e8 c2 91 11 fa 8b 13 83 c2 0c 31 c0 ee 41 80 3c 2c 00 74 08 48 89 df e8 ab 91 11 fa 8b 13 83 c2 0e b0 18 ee <41> 80 3c 2c 00 74 08 48 89 df e8 94 91 11 fa 8b 13 83 c2 0e b0 41
RSP: 0018:ffffc90003837ab8 EFLAGS: 00000202
RAX: 0000000000000018 RBX: ffff88802e8991d0 RCX: ffff88802e090000
RDX: 000000000000200e RSI: 0000000002018272 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000040 R09: fffffbfff2119058
R10: fffffbfff2119058 R11: 1ffffffff2119057 R12: 1ffff11005d1323a
R13: 0000000000a32498 R14: 1ffff1100bb01892 R15: 0000000000146494
FS: 0000555564c65500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564b88277a38 CR3: 00000000581ea000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
comedi_device_attach+0x514/0x700 drivers/comedi/drivers.c:1006
do_devconfig_ioctl drivers/comedi/comedi_fops.c:868 [inline]
comedi_unlocked_ioctl+0x5a6/0x1050 drivers/comedi/comedi_fops.c:2173
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fbf3dd8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe2f28abc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fbf3dfe5fa0 RCX: 00007fbf3dd8f749
RDX: 00002000000000c0 RSI: 0000000040946400 RDI: 0000000000000003
RBP: 00007fbf3de13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbf3dfe5fa0 R14: 00007fbf3dfe5fa0 R15: 0000000000000003