INFO: task syz.2.19:5985 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.19 state:D stack:26664 pid:5985 ppid:5884 flags:0x00004004
Call Trace:
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
comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
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: 0033:0x7ff4e178f749
RSP: 002b:00007fffa128e4d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ff4e19e5fa0 RCX: 00007ff4e178f749
RDX: 0000000000000400 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007ff4e1813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff4e19e5fa0 R14: 00007ff4e19e5fa0 R15: 0000000000000004
INFO: task syz.1.18:5988 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:26664 pid:5988 ppid:5880 flags:0x00004004
Call Trace:
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
comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
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: 0033:0x7f1da838f749
RSP: 002b:00007ffd89f094b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f1da85e5fa0 RCX: 00007f1da838f749
RDX: 0000000000000400 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007f1da8413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1da85e5fa0 R14: 00007f1da85e5fa0 R15: 0000000000000004
INFO: task syz.0.17:5993 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:26664 pid:5993 ppid:5881 flags:0x00004004
Call Trace:
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
comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
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: 0033:0x7f544118f749
RSP: 002b:00007ffd7bc74838 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f54413e5fa0 RCX: 00007f544118f749
RDX: 0000000000000400 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007f5441213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f54413e5fa0 R14: 00007f54413e5fa0 R15: 0000000000000004
Showing all locks held in the system:
3 locks held by kworker/u4:1/12:
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
3 locks held by kworker/u4:4/59:
#0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc900015a7d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc900015a7d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffffffff8dfb5448 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:286
3 locks held by kworker/u4:5/71:
#0: ffff88802c27fd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff88802c27fd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc900015d7d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc900015d7d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffffffff8dfb5448 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xd0/0x14e0 net/ipv6/addrconf.c:4158
2 locks held by getty/5528:
#0: ffff88802cde40a0 (&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 syz.3.20/5967:
1 lock held by syz.2.19/5985:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.1.18/5988:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.0.17/5993:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.4.21/6042:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.5.22/6077:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.6.23/6104:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.7.24/6105:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.8.25/6138:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.9.26/6179:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.3.27/6200:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.2.28/6201:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.1.29/6223:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.0.30/6256:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.4.31/6294:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.5.32/6295:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.6.33/6322:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.7.34/6353:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.8.35/6403:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.9.36/6411:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.3.37/6426:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.2.38/6446:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.1.39/6485:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.0.40/6500:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.4.41/6530:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.5.42/6542:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz.6.43/6575:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
1 lock held by syz-executor/6596:
#0: ffffffff8dfb5448 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
#0: ffffffff8dfb5448 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6469
1 lock held by syz.7.44/6601:
#0: ffff88814c7178f8 (&dev->mutex#3){+.+.}-{3:3}, at: comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2816
2 locks held by syz-executor/6608:
#0: ffffffff8dfb5448 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
#0: ffffffff8dfb5448 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6469
#1: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
#1: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x448/0x830 kernel/rcu/tree_exp.h:1004
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 29 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+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
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5967 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:223 [inline]
RIP: 0010:multiq3_attach+0x5e5/0x940 drivers/comedi/drivers/multiq3.c:316
Code: 89 dc 49 c1 ec 03 45 31 ed 41 80 3c 2c 00 74 08 48 89 df e8 4d a8 db f9 44 89 e8 83 e0 38 0d 40 06 00 00 8b 13 83 c2 06 66 ef <41> 80 3c 2c 00 74 08 48 89 df e8 2c a8 db f9 8b 13 83 c2 0e b0 06
RSP: 0018:ffffc90003057ab8 EFLAGS: 00000206
RAX: 0000000000000678 RBX: ffff88814c7179d0 RCX: ffff888026d08000
RDX: 0000000000002006 RSI: 0000000002018272 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000040 R09: 1ffffffff21b28b0
R10: dffffc0000000000 R11: fffffbfff21b28b1 R12: 1ffff110298e2f3a
R13: 00000000014bc2f8 R14: 1ffff11005e70c92 R15: 0000000000297860
FS: 0000555555dec500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4687117e9c CR3: 000000007c304000 CR4: 00000000003506e0
Call Trace:
comedi_device_attach+0x518/0x710 drivers/comedi/drivers.c:1006
do_devconfig_ioctl drivers/comedi/comedi_fops.c:872 [inline]
comedi_unlocked_ioctl+0x606/0xfe0 drivers/comedi/comedi_fops.c:2178
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
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: 0033:0x7fe46a98f749
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:00007ffd5a54e248 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fe46abe5fa0 RCX: 00007fe46a98f749
RDX: 00002000000000c0 RSI: 0000000040946400 RDI: 0000000000000003
RBP: 00007fe46aa13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe46abe5fa0 R14: 00007fe46abe5fa0 R15: 0000000000000003