INFO: task syz.7.9651:11597 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.7.9651 state:D stack:28120 pid:11597 tgid:11596 ppid:4471 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5387 [inline]
__schedule+0x17b4/0x5680 kernel/sched/core.c:7188
__schedule_loop kernel/sched/core.c:7267 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7282
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7339
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7f7/0x1550 kernel/locking/mutex.c:820
device_lock include/linux/device.h:1040 [inline]
usbdev_open+0x182/0x770 drivers/usb/core/devio.c:1054
chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411
do_dentry_open+0x785/0x14e0 fs/open.c:947
vfs_open+0x3b/0x340 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x2e08/0x3860 fs/namei.c:4858
do_file_open+0x23e/0x4a0 fs/namei.c:4887
do_sys_openat2+0x113/0x200 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_sys_openat fs/open.c:1386 [inline]
__se_sys_openat fs/open.c:1381 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1381
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8a8575d60e
RSP: 002b:00007f8a86662b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f8a866636c0 RCX: 00007f8a8575d60e
RDX: 0000000000000002 RSI: 00007f8a86662c00 RDI: ffffffffffffff9c
RBP: 00007f8a86662c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f8a85a16038 R14: 00007f8a85a15fa0 R15: 00007f8a85b3fa48
INFO: task syz.7.9651:11598 blocked for more than 144 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.9651 state:D stack:28120 pid:11598 tgid:11596 ppid:4471 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5387 [inline]
__schedule+0x17b4/0x5680 kernel/sched/core.c:7188
__schedule_loop kernel/sched/core.c:7267 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7282
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7339
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7f7/0x1550 kernel/locking/mutex.c:820
device_lock include/linux/device.h:1040 [inline]
usbdev_open+0x182/0x770 drivers/usb/core/devio.c:1054
chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411
do_dentry_open+0x785/0x14e0 fs/open.c:947
vfs_open+0x3b/0x340 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x2e08/0x3860 fs/namei.c:4858
do_file_open+0x23e/0x4a0 fs/namei.c:4887
do_sys_openat2+0x113/0x200 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_sys_openat fs/open.c:1386 [inline]
__se_sys_openat fs/open.c:1381 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1381
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8a8575d60e
RSP: 002b:00007f8a86641b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f8a866426c0 RCX: 00007f8a8575d60e
RDX: 0000000000000002 RSI: 00007f8a86641c00 RDI: ffffffffffffff9c
RBP: 00007f8a86641c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f8a85a16128 R14: 00007f8a85a16090 R15: 00007f8a85b3fa48
Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5380:
#0: ffff8880363f70a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0 drivers/tty/n_tty.c:2211
5 locks held by kworker/0:12/16571:
3 locks held by kworker/u8:10/7654:
#0: ffff888031ee7940 ((wq_completion)l2tp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
#0: ffff888031ee7940 ((wq_completion)l2tp){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
#1: ffffc90006047c40 ((work_completion)(&session->del_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
#1: ffffc90006047c40 ((work_completion)(&session->del_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
#2: ffffffff8fdcefc0 (rtnl_mutex){+.+.}-{4:4}, at: l2tp_eth_delete+0x1f/0x100 net/l2tp/l2tp_eth.c:154
3 locks held by kworker/u8:23/9446:
#0: ffff88801ae84140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
#0: ffff88801ae84140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
#1: ffffc90006cafc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
#1: ffffc90006cafc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
#2: ffffffff8fdcefc0 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
1 lock held by syz.7.9651/11597:
#0: ffff88802a6b71d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline]
#0: ffff88802a6b71d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x182/0x770 drivers/usb/core/devio.c:1054
1 lock held by syz.7.9651/11598:
#0: ffff88802a6b71d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline]
#0: ffff88802a6b71d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x182/0x770 drivers/usb/core/devio.c:1054
2 locks held by syz.5.10176/16844:
#0: ffffffff8fdcefc0 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff8fdcefc0 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3438
#1: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#1: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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:162 [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:353 [inline]
watchdog+0xfd3/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 7654 Comm: kworker/u8:10 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: l2tp l2tp_session_del_work
RIP: 0010:__bfs kernel/locking/lockdep.c:1753 [inline]
RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1860 [inline]
RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2796 [inline]
RIP: 0010:check_prev_add kernel/locking/lockdep.c:3169 [inline]
RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3284 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3908 [inline]
RIP: 0010:__lock_acquire+0x1821/0x2cf0 kernel/locking/lockdep.c:5237
Code: 00 0f 83 8a 01 00 00 4e 8b 24 fd 40 58 41 96 ff c0 25 ff 0f 00 00 89 05 0d 1e a0 14 4d 85 e4 0f 84 b2 01 00 00 49 8b 44 24 10 <48> 85 c0 0f 84 1c 0d 00 00 8b 0d f8 1d a0 14 39 48 5c 0f 84 67 ff
RSP: 0018:ffffc90006046fe0 EFLAGS: 00000086
RAX: ffffffff93e1f760 RBX: 00000000000003fd RCX: ffffffff93e2acd0
RDX: ffffffff96debed8 RSI: ffff88801dfb4a00 RDI: 00000000000003fd
RBP: 771cd789fac3fa84 R08: ffffc90006046fa8 R09: 0000000000000020
R10: 0000000000000003 R11: ffffffff81a20c90 R12: ffffffff96c462d8
R13: ffff88801dfb4a00 R14: ffff88801dfb3d80 R15: 0000000000000011
FS: 0000000000000000(0000) GS:ffff888125290000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000f000 CR3: 000000004b73a000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 00000000ffff000c DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
seqcount_lockdep_reader_access+0x55/0x100 include/linux/seqlock.h:73
ktime_get+0x45/0x220 kernel/time/timekeeping.c:965
clockevents_program_event+0x290/0x630 kernel/time/clockevents.c:363
hrtimer_rearm kernel/time/hrtimer.c:2039 [inline]
__hrtimer_rearm_deferred+0x270/0x450 kernel/time/hrtimer.c:2059
hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:53 [inline]
hrtimer_rearm_deferred include/linux/hrtimer_rearm.h:62 [inline]
irqentry_exit_to_kernel_mode_after_preempt include/linux/irq-entry-common.h:513 [inline]
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:550 [inline]
irqentry_exit+0x6a0/0x730 kernel/entry/common.c:164
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:198
Code: f7 e8 1d 85 f7 f5 f7 c3 00 02 00 00 74 05 e8 70 18 23 f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 64 07 e9 f5 65 8b 05 ed 40 8e 07 85 c0 74 18 5b 41 5e e9 51 48
RSP: 0018:ffffc90006047430 EFLAGS: 00000206
RAX: 0000000000000002 RBX: 0000000000000292 RCX: 0000000080000001
RDX: 0000000000000006 RSI: ffffffff8dfa4f23 RDI: 0000000000000001
RBP: 0000000000000000 R08: ffffffff9030a1f7 R09: 1ffffffff206143e
R10: dffffc0000000000 R11: fffffbfff206143f R12: ffff8880324b5010
R13: ffff8880324b5000 R14: ffffffff9a673740 R15: 1ffff11006496a02
debug_object_activate+0x320/0x580 lib/debugobjects.c:853
debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
__call_rcu_common kernel/rcu/tree.c:3116 [inline]
call_rcu+0x43/0x890 kernel/rcu/tree.c:3251
kernfs_put+0x259/0x520 fs/kernfs/dir.c:618
kernfs_remove_by_name_ns+0xc8/0x140 fs/kernfs/dir.c:1799
kernfs_remove_by_name include/linux/kernfs.h:639 [inline]
remove_files fs/sysfs/group.c:28 [inline]
sysfs_remove_group+0xfc/0x2e0 fs/sysfs/group.c:328
sysfs_remove_groups+0x54/0xb0 fs/sysfs/group.c:352
device_remove_groups drivers/base/core.c:2844 [inline]
device_remove_attrs+0x229/0x280 drivers/base/core.c:2980
device_del+0x51f/0x8f0 drivers/base/core.c:3894
unregister_netdevice_many_notify+0x1d5f/0x22c0 net/core/dev.c:12453
unregister_netdevice_many net/core/dev.c:12481 [inline]
unregister_netdevice_queue+0x31f/0x360 net/core/dev.c:12291
unregister_netdevice include/linux/netdevice.h:3444 [inline]
l2tp_eth_delete+0xdc/0x100 net/l2tp/l2tp_eth.c:157
l2tp_session_del_work+0x724/0x860 net/l2tp/l2tp_core.c:1752
process_one_work kernel/workqueue.c:3302 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245