INFO: task syz-executor:8676 blocked for more than 145 seconds. Tainted: G L syzkaller #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:20280 pid:8676 tgid:8676 ppid:1 task_flags:0x40054c flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5402 [inline] __schedule+0x16f9/0x5500 kernel/sched/core.c:7204 __schedule_loop kernel/sched/core.c:7283 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7579 rt_mutex_slowlock_block+0x508/0x680 kernel/locking/rtmutex.c:1666 __rt_mutex_slowlock kernel/locking/rtmutex.c:1743 [inline] __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1783 [inline] rt_mutex_slowlock+0x2dc/0x780 kernel/locking/rtmutex.c:1823 __rt_mutex_lock kernel/locking/rtmutex.c:1838 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline] mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578 rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 netdev_run_todo+0x2fc/0x12b0 net/core/dev.c:11720 tun_detach drivers/net/tun.c:647 [inline] tun_chr_close+0x13f/0x1c0 drivers/net/tun.c:3505 __fput+0x461/0xa70 fs/file_table.c:510 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x70f/0x22c0 kernel/exit.c:1004 do_group_exit+0x21b/0x2d0 kernel/exit.c:1147 get_signal+0x1284/0x1330 kernel/signal.c:3038 arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0xa9/0x680 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: 0033:0x7f93b58dd68e RSP: 002b:00007ffca70e9178 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: 000000000000008c RBX: 000055555ef17500 RCX: 00007f93b58dd68e RDX: 000000000000008c RSI: 00007f93b66c4670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007ffca70e91f4 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f93b66c4670 R15: 0000000000000000 Showing all locks held in the system: 4 locks held by ktimers/0/16: #0: ffffffff8de613c0 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163 #1: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163 #2: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #2: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #2: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: process_backlog+0x271/0xc60 net/core/dev.c:6667 #3: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #3: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #3: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: nf_hook include/linux/netfilter.h:242 [inline] #3: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: NF_HOOK+0x9e/0x3c0 include/linux/netfilter.h:316 6 locks held by ksoftirqd/1/31: #0: ffffffff8de613c0 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163 #1: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163 #2: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #2: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #2: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: process_backlog+0x271/0xc60 net/core/dev.c:6667 #3: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #3: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #3: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: nf_hook include/linux/netfilter.h:242 [inline] #3: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: NF_HOOK+0x9e/0x3c0 include/linux/netfilter.h:316 #4: ffffffff8e791300 (fill_pool_map-wait-type-override){+.+.}-{3:3}, at: debug_objects_fill_pool+0xa7/0x110 lib/debugobjects.c:751 #5: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #5: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #5: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1181 [inline] #5: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0xa6/0x2550 arch/x86/kernel/unwind_orc.c:495 1 lock held by khungtaskd/39: #0: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6777 6 locks held by kworker/u8:5/68: #0: ffff88801b69e138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x897/0x1630 kernel/workqueue.c:3293 #1: ffffc9000153fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x8be/0x1630 kernel/workqueue.c:3294 #2: ffffffff8f380c60 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:673 #3: ffff888025467160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #3: ffff888025467160 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:124 [inline] #3: ffff888025467160 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x129/0x420 net/devlink/core.c:555 #4: ffff888034806310 (&devlink->lock_key#6){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:292 [inline] #4: ffff888034806310 (&devlink->lock_key#6){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:125 [inline] #4: ffff888034806310 (&devlink->lock_key#6){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x142/0x420 net/devlink/core.c:555 #5: ffffffff8dfd0e30 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 2 locks held by getty/5368: #0: ffff8880286b60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003cc62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211 3 locks held by kworker/1:6/5757: #0: ffff88813fe4f938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x897/0x1630 kernel/workqueue.c:3293 #1: ffffc90005e47c40 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_one_work+0x8be/0x1630 kernel/workqueue.c:3294 #2: ffffffff8dfd0e30 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 1 lock held by syz.1.677/8553: #0: ffffffff8dfd0e30 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 1 lock held by syz-executor/8676: #0: ffffffff8dfd0e30 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 1 lock held by syz-executor/8679: #0: ffffffff8dfd0e30 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 1 lock held by syz-executor/8688: #0: ffffffff8dfd0e30 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 1 lock held by syz-executor/8697: #0: ffffffff8dfd0e30 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 1 lock held by syz-executor/8698: #0: ffffffff8dfd0e30 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 2 locks held by syz-executor/8759: #0: ffffffff8f380c60 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575 #1: ffffffff8dfd0e30 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 2 locks held by syz-executor/8762: #0: ffffffff8f380c60 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575 #1: ffffffff8dfd0e30 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 2 locks held by syz-executor/8858: #0: ffffffff8f380c60 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575 #1: ffffffff8dfd0e30 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 2 locks held by syz-executor/8871: #0: ffff88805f6a4f80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:500 [inline] #0: ffff88805f6a4f80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x5a0 net/bluetooth/hci_core.c:2679 #1: ffff88805f6a40b0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x67c/0x1150 net/bluetooth/hci_sync.c:5388 2 locks held by syz-executor/8878: #0: ffffffff8f380c60 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575 #1: ffffffff8dfd0e30 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 2 locks held by syz-executor/8890: #0: ffffffff8f380c60 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575 #1: ffffffff8dfd0e30 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 2 locks held by syz-executor/8905: #0: ffffffff8f380c60 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575 #1: ffffffff8f390178 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x2d5/0x850 net/ipv4/ip_tunnel.c:1146 1 lock held by syz-executor/8942: #0: ffffffff8f390178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f390178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8f390178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4150 1 lock held by syz-executor/8949: #0: ffffffff8f390178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f390178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8f390178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4150 1 lock held by syz-executor/8952: #0: ffffffff8f390178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f390178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8f390178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4150 2 locks held by syz-executor/8962: #0: ffffffff8e111470 (remove_cache_srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline] #0: ffffffff8e111470 (remove_cache_srcu){.+.+}-{0:0}, at: srcu_read_lock+0x27/0x60 include/linux/srcu.h:294 #1: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #1: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #1: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1181 [inline] #1: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0xa6/0x2550 arch/x86/kernel/unwind_orc.c:495 3 locks held by syz-executor/8981: #0: ffffffff8e00b170 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x295c/0x43d0 kernel/fork.c:2395 #1: ffffffff8e00ae78 (css_set_lock){+.+.}-{3:3}, at: spin_lock_irq include/linux/spinlock_rt.h:96 [inline] #1: ffffffff8e00ae78 (css_set_lock){+.+.}-{3:3}, at: cgroup_post_fork+0xc8/0x900 kernel/cgroup/cgroup.c:6947 #2: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #2: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #2: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline] #2: ffffffff8dfcac60 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 39 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP 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:122 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65 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: 16 Comm: ktimers/0 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline] RIP: 0010:check_wait_context kernel/locking/lockdep.c:4881 [inline] RIP: 0010:__lock_acquire+0x524/0x2d10 kernel/locking/lockdep.c:5189 Code: 00 48 83 c3 28 41 89 c4 49 39 cf 0f 8d c7 00 00 00 49 83 ff 31 0f 83 83 00 00 00 8b 03 25 ff 1f 00 00 48 0f a3 05 4c 3a dc 11 <73> 10 48 69 c0 c8 00 00 00 48 8d 88 d0 f4 1d 93 eb 32 83 3d 53 ca RSP: 0018:ffffc90000156a30 EFLAGS: 00000003 RAX: 000000000000000b RBX: ffff88801d680c98 RCX: 0000000000000004 RDX: 0000000000000003 RSI: 0000000000000003 RDI: 0000000000000000 RBP: ffff88801d680ca0 R08: ffffffff8176c406 R09: ffffffff8dfcac60 R10: ffffc90000156d38 R11: ffffffff81b02a50 R12: 0000000000000003 R13: ffff88801d680ca0 R14: ffff88801d680000 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff888125ecd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f52aaed5f40 CR3: 0000000034600000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5870 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:2700 [inline] slab_free mm/slub.c:6284 [inline] kfree+0x1c5/0x6c0 mm/slub.c:6599 skb_kfree_head net/core/skbuff.c:1075 [inline] skb_free_head net/core/skbuff.c:1087 [inline] skb_release_data+0x828/0xa60 net/core/skbuff.c:1114 skb_release_all net/core/skbuff.c:1189 [inline] __kfree_skb+0x5d/0x210 net/core/skbuff.c:1203 nft_synproxy_eval_v4+0x352/0x4e0 net/netfilter/nft_synproxy.c:61 nft_synproxy_do_eval+0x305/0x580 net/netfilter/nft_synproxy.c:142 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x48d/0x1ae0 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x360/0x4b0 net/netfilter/nft_chain_filter.c:162 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6204 [inline] __netif_receive_skb net/core/dev.c:6317 [inline] process_backlog+0x569/0xc60 net/core/dev.c:6668 __napi_poll+0xab/0x550 net/core/dev.c:7727 napi_poll net/core/dev.c:7790 [inline] net_rx_action+0x696/0xe00 net/core/dev.c:7947 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:626 __do_softirq kernel/softirq.c:660 [inline] run_ktimerd+0x69/0x100 kernel/softirq.c:1155 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