INFO: task syz.3.897:9248 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.897 state:D stack:28856 pid:9248 tgid:9244 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+0x231/0x6a0 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/0x4e0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f019ab8eec9
RSP: 002b:00007f019baec038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f019ade6090 RCX: 00007f019ab8eec9
RDX: 0000000000002000 RSI: 0000200000000040 RDI: 00000000ffffff9c
RBP: 00007f019ac11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f019ade6128 R14: 00007f019ade6090 R15: 00007ffc79ee0ab8
INFO: task syz.0.931:9379 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.931 state:D stack:28792 pid:9379 tgid:9377 ppid:5822 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+0x231/0x6a0 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/0x4e0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f75f158eec9
RSP: 002b:00007f75f24d3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f75f17e6090 RCX: 00007f75f158eec9
RDX: 0000000000002000 RSI: 0000200000000040 RDI: 00000000ffffff9c
RBP: 00007f75f1611f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f75f17e6128 R14: 00007f75f17e6090 R15: 00007ffeb6132e68
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e1c4120 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e1c4120 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e1c4120 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
2 locks held by getty/5586:
#0: ffff8880350cd0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900036c32f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
1 lock held by syz.2.788/8806:
1 lock held by syz.3.897/9248:
#0: ffff88814cdca0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xe0/0x5a0 drivers/comedi/comedi_fops.c:2868
1 lock held by syz.0.931/9379:
#0: ffff88814cdca0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xe0/0x5a0 drivers/comedi/comedi_fops.c:2868
4 locks held by syz.4.1655/11660:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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+0x3c2/0x780 kernel/kthread.c:463
ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 7004 Comm: kworker/u8:11 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:cr4_update_irqsoff+0x57/0xb0 arch/x86/kernel/cpu/common.c:457
Code: c1 e9 03 83 c0 03 0f b6 14 11 38 d0 7c 04 84 d2 75 55 8b 05 1f 82 fd 0e 85 c0 74 0b 65 8b 05 e8 0e 18 12 85 c0 74 1c 48 f7 d6 <48> 89 f7 48 21 ef 48 09 df 48 39 fd 75 1c 48 83 c4 08 5b 5d c3 cc
RSP: 0018:ffffc9000427f888 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffffffff20bec9e
RDX: 0000000000000000 RSI: fffffffffffffeff RDI: 0000000000000000
RBP: 00000000003526f0 R08: 0000000000000000 R09: fffffbfff1c6d626
R10: ffffffff8e36b133 R11: 0000000000000000 R12: ffff888079d14b40
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000010000
FS: 0000000000000000(0000) GS:ffff888124f85000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000402030 CR3: 000000000df82000 CR4: 00000000003526f0
Call Trace:
cr4_clear_bits_irqsoff arch/x86/include/asm/tlbflush.h:38 [inline]
cr4_update_pce_mm arch/x86/mm/tlb.c:764 [inline]
cr4_update_pce_mm arch/x86/mm/tlb.c:752 [inline]
switch_mm_irqs_off+0x52c/0x7f0 arch/x86/mm/tlb.c:948
switch_mm+0x17/0x70 arch/x86/mm/tlb.c:612
use_temporary_mm+0x101/0x150 arch/x86/mm/tlb.c:1005
__text_poke+0x3ac/0xb70 arch/x86/kernel/alternative.c:2488
smp_text_poke_batch_finish+0x4f1/0xdb0 arch/x86/kernel/alternative.c:2885
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
jump_label_update+0x376/0x550 kernel/jump_label.c:919
static_key_disable_cpuslocked+0x158/0x1c0 kernel/jump_label.c:240
static_key_disable+0x1a/0x20 kernel/jump_label.c:248
toggle_allocation_gate mm/kfence/core.c:857 [inline]
toggle_allocation_gate+0x145/0x280 mm/kfence/core.c:844
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
kthread+0x3c2/0x780 kernel/kthread.c:463
ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245