INFO: task syz.1.1066:8916 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1066 state:D stack:22496 pid:8916 tgid:8916 ppid:5611 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x16ec/0x5620 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7564
rt_mutex_slowlock_block+0x508/0x680 kernel/locking/rtmutex.c:1662
__rt_mutex_slowlock kernel/locking/rtmutex.c:1739 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1779 [inline]
rt_mutex_slowlock+0x2dc/0x780 kernel/locking/rtmutex.c:1819
__rt_mutex_lock kernel/locking/rtmutex.c:1834 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:535 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:553
rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
netdev_run_todo+0x2e0/0xde0 net/core/dev.c:11694
tun_detach drivers/net/tun.c:640 [inline]
tun_chr_close+0x13f/0x1c0 drivers/net/tun.c:3441
__fput+0x461/0xa70 fs/file_table.c:510
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0x193/0x680 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1a18adce59
RSP: 002b:00007ffcdf3d0e08 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f1a18d57da0 RCX: 00007f1a18adce59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f1a18d57da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00007f1a18d57cb0 R11: 0000000000000246 R12: 0000000000086e8a
R13: 00007f1a18d55fac R14: 0000000000086e57 R15: 00007f1a18d55fa0
Showing all locks held in the system:
4 locks held by rcuc/0/20:
5 locks held by ksoftirqd/1/30:
1 lock held by khungtaskd/38:
#0: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:16/1325:
#0: ffff88801a074138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88801a074138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc900069afc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc900069afc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
#2: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
2 locks held by getty/5360:
#0: ffff888036ca40a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211
3 locks held by kworker/0:4/5731:
#0: ffff88801a037938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88801a037938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc90005227c40 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc90005227c40 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
#2: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104
4 locks held by kworker/u8:2/7916:
1 lock held by syz.2.1059/8893:
#0: ffffffff8dfce1b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
1 lock held by syz.1.1066/8916:
#0: ffffffff8dfce1b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
1 lock held by syz-executor/8946:
#0: ffffffff8dfce1b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
1 lock held by syz-executor/8984:
#0: ffffffff8dfce1b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
2 locks held by syz.0.1089/9003:
#0: ffffffff8ead1c28 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8ead1c28 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8ead1c28 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
#1: ffffffff8dfce1b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
1 lock held by syz-executor/9048:
#0: ffffffff8dfce1b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
2 locks held by syz-executor/9139:
#0: ffffffff8f340e20 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575
#1: ffffffff8dfce1b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
1 lock held by syz.3.1118/9142:
#0: ffffffff8dfce1b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
2 locks held by syz-executor/9156:
#0: ffffffff8f340e20 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575
#1: ffffffff8dfce1b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
1 lock held by syz-executor/9173:
#0: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x41/0x1c0 drivers/net/tun.c:3441
1 lock held by syz.4.1126/9193:
#0: ffffffff8dfce1b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
2 locks held by syz-executor/9209:
#0: ffffffff8ead1c28 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8ead1c28 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8ead1c28 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
#1: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#1: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4109
2 locks held by syz-executor/9240:
#0: ffffffff8f889050 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8f889050 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8f889050 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
#1: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#1: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4109
2 locks held by syz-executor/9250:
#0: ffffffff8f340e20 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575
#1: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline]
#1: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: register_netdev+0x18/0x60 net/core/dev.c:11536
1 lock held by syz-executor/9276:
#0: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4109
1 lock held by syz-executor/9291:
#0: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff8f34fb78 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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 N[ 710.547389][ T38] Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 20 Comm: rcuc/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__lock_acquire+0x846/0x2cf0 kernel/locking/lockdep.c:-1
Code: 00 00 c1 ed 03 81 e5 00 60 00 00 09 c5 48 89 d8 48 c1 e8 20 29 c5 89 c1 c1 c1 04 31 e9 01 d8 29 cb 89 ca c1 c2 06 31 da 01 c1 <29> d0 89 d6 c1 c6 08 31 c6 01 ca 29 f1 89 f3 c1 c3 10 31 cb 01 d6
RSP: 0018:ffffc900001974d0 EFLAGS: 00000087
RAX: 00000000f7359542 RBX: 000000002014a7a7 RCX: 00000000cbb875b4
RDX: 0000000000acbb12 RSI: ffff88801d290c70 RDI: ffff88801d290000
RBP: 00000000fd6232e2 R08: ffffffff8176c226 R09: ffffffff8dfc8000
R10: ffffc900001977d8 R11: ffffffff81af86c0 R12: ffff88801d290c70
R13: ffff88801d290c70 R14: ffff88801d290000 R15: 0000000000000003
FS: 0000000000000000(0000) GS:ffff888126183000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcabf238f20 CR3: 00000000116ac000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock include/linux/rcupdate.h:838 [inline]
class_rcu_constructor include/linux/rcupdate.h:1181 [inline]
unwind_next_frame+0xc3/0x2550 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2689 [inline]
slab_free mm/slub.c:6251 [inline]
kmem_cache_free+0x187/0x6c0 mm/slub.c:6378
dst_destroy+0x235/0x350 net/core/dst.c:122
rcu_do_batch kernel/rcu/tree.c:2617 [inline]
rcu_core kernel/rcu/tree.c:2869 [inline]
rcu_cpu_kthread+0x99e/0x1470 kernel/rcu/tree.c:2957
smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
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