INFO: task syz.6.505:7924 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.505 state:D stack:27976 pid:7924 tgid:7922 ppid:6041 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7008
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776
comedi_open+0xc0/0x5e0 drivers/comedi/comedi_fops.c:2982
chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411
do_dentry_open+0x785/0x14e0 fs/open.c:949
vfs_open+0x3b/0x340 fs/open.c:1081
do_open fs/namei.c:4677 [inline]
path_openat+0x2e08/0x3860 fs/namei.c:4836
do_file_open+0x23e/0x4a0 fs/namei.c:4865
do_sys_openat2+0x113/0x200 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1383
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9b8d99c819
RSP: 002b:00007f9b8e7c9028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f9b8dc15fa0 RCX: 00007f9b8d99c819
RDX: 0000000000000400 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007f9b8da32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9b8dc16038 R14: 00007f9b8dc15fa0 R15: 00007ffc9e122728
INFO: task syz.6.505:7927 blocked for more than 146 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.505 state:D stack:26920 pid:7927 tgid:7922 ppid:6041 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7008
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776
comedi_open+0xc0/0x5e0 drivers/comedi/comedi_fops.c:2982
chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411
do_dentry_open+0x785/0x14e0 fs/open.c:949
vfs_open+0x3b/0x340 fs/open.c:1081
do_open fs/namei.c:4677 [inline]
path_openat+0x2e08/0x3860 fs/namei.c:4836
do_file_open+0x23e/0x4a0 fs/namei.c:4865
do_sys_openat2+0x113/0x200 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1383
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9b8d99c819
RSP: 002b:00007f9b8e7a8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f9b8dc16090 RCX: 00007f9b8d99c819
RDX: 0000000000000400 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007f9b8da32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9b8dc16128 R14: 00007f9b8dc16090 R15: 00007ffc9e122728
Showing all locks held in the system:
3 locks held by rcu_exp_gp_kthr/18:
#0:
ffff8880b863ae60 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xb6/0x150 kernel/sched/core.c:655
#1: ffff8880b8624588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933
#2: ffff88807b2c6610 (&p->pi_lock){-.-.}-{2:2}, at: class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:570 [inline]
#2: ffff88807b2c6610 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0x66/0x1390 kernel/sched/core.c:4130
1 lock held by khungtaskd/31:
#0: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
1 lock held by udevd/5190:
1 lock held by dhcpcd/5486:
#0: ffffffff8fbd0888 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8fbd0888 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8fbd0888 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4093
2 locks held by getty/5577:
#0: ffff88803229e0a0 (&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+0x45c/0x13c0 drivers/tty/n_tty.c:2211
2 locks held by syz-executor/5839:
#0: ffff88804ad1e0e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88804ad1e0e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88804ad1e0e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
#1: ffffffff8e7648b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#1: ffffffff8e7648b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
4 locks held by kworker/u8:12/6386:
#0: ffff88801bad6948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#0: ffff88801bad6948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
#1: ffffc900039a7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
#1: ffffc900039a7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
#2: ffffffff8fbc2110 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:675
#3: ffffffff8e7648b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#3: ffffffff8e7648b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
1 lock held by syz.0.486/7849:
1 lock held by syz.6.505/7924:
#0: ffff888030b8a8f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5e0 drivers/comedi/comedi_fops.c:2982
1 lock held by syz.6.505/7927:
#0: ffff888030b8a8f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5e0 drivers/comedi/comedi_fops.c:2982
1 lock held by syz.7.647/8592:
#0: ffff888030b8a8f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5e0 drivers/comedi/comedi_fops.c:2982
2 locks held by syz.1.861/9510:
#0: ffffffff9013aeb0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff9013aeb0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff9013aeb0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
#1: ffffffff8fbd0888 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8fbd0888 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#1: ffffffff8fbd0888 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4093
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xfd9/0x1030 kernel/hung_task.c:515
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 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: 7849 Comm: syz.0.486 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:c6xdigio_chk_status drivers/comedi/drivers/c6xdigio.c:54 [inline]
RIP: 0010:c6xdigio_write_data drivers/comedi/drivers/c6xdigio.c:66 [inline]
RIP: 0010:c6xdigio_get_encoder_bits drivers/comedi/drivers/c6xdigio.c:82 [inline]
RIP: 0010:c6xdigio_encoder_read drivers/comedi/drivers/c6xdigio.c:119 [inline]
RIP: 0010:c6xdigio_encoder_insn_read+0x176/0x7a0 drivers/comedi/drivers/c6xdigio.c:201
Code: 41 0f b7 17 0f b6 44 24 04 ee e8 d5 93 6c f8 90 bb 01 00 00 00 43 80 3c 2c 00 74 08 4c 89 ff e8 70 c8 26 f9 41 8b 17 ff c2 ec <0f> b6 e8 bf ff 00 00 00 89 ee e8 6b 7c bc f8 bf 14 00 00 00 89 de
RSP: 0018:ffffc9000d24f8b8 EFLAGS: 00000202
RAX: ffffffff890946e9 RBX: 0000000000000005 RCX: 0000000000080000
RDX: 0000000000000402 RSI: 000000000007ffff RDI: 0000000000080000
RBP: 00000000000000e9 R08: ffff888033700000 R09: 0000000000000004
R10: 000000000c000003 R11: ffffffff890944e0 R12: 1ffff1100617153a
R13: dffffc0000000000 R14: 0000000089094905 R15: ffff888030b8a9d0
FS: 00007fe9e9bb06c0(0000) GS:ffff888125454000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555708abae8 CR3: 000000002a6cf000 CR4: 0000000000350ef0
Call Trace:
parse_insn+0xa3e/0x1b20 drivers/comedi/comedi_fops.c:1565
do_insn_ioctl+0x174/0x5a0 drivers/comedi/comedi_fops.c:1790
comedi_unlocked_ioctl+0xe06/0x1af0 drivers/comedi/comedi_fops.c:2422
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe9e8d9c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe9e9bb0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fe9e9015fa0 RCX: 00007fe9e8d9c819
RDX: 0000200000000000 RSI: 000000008028640c RDI: 0000000000000004
RBP: 00007fe9e8e32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe9e9016038 R14: 00007fe9e9015fa0 R15: 00007ffffb39ce48