INFO: task syz-executor:28745 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-executor state:D stack:22312 pid:28745 tgid:28745 ppid:1 task_flags:0x400140 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:712 [inline] __mutex_lock+0x7f5/0x1550 kernel/locking/mutex.c:806 del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61d/0xb90 fs/read_write.c:688 ksys_write+0x150/0x270 fs/read_write.c:740 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: 0033:0x7f99f6f5d04e RSP: 002b:00007f99f733f1e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000555565e65500 RCX: 00007f99f6f5d04e RDX: 0000000000000001 RSI: 00007f99f733f270 RDI: 0000000000000005 RBP: 00007f99f7033514 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007f99f733f270 R14: 00007f99f7d44620 R15: 0000000000000003 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e95cce0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e95cce0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8e95cce0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:9/3558: 1 lock held by dhcpcd/5505: #0: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x32b/0x1b30 net/ipv4/devinet.c:1120 2 locks held by getty/5598: #0: ffff8880327260a0 (&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 2 locks held by kworker/u8:10/6155: #0: ffff88801ae9c940 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline] #0: ffff88801ae9c940 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385 #1: ffffc9000547fc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline] #1: ffffc9000547fc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385 8 locks held by kworker/u8:23/8981: 3 locks held by kworker/u8:6/19124: #0: ffff88801ae9c140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline] #0: ffff88801ae9c140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385 #1: ffffc900042bfc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline] #1: ffffc900042bfc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385 #2: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313 1 lock held by syz-executor/28673: #0: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3438 4 locks held by syz-executor/28745: #0: ffff888033d40410 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2724 [inline] #0: ffff888033d40410 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff8880618c5880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff888029a654b8 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888029a654b8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f64fd00 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 7 locks held by syz-executor/28751: #0: ffff888033d40410 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2724 [inline] #0: ffff888033d40410 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff88807f8fdc80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff888029a654b8 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888029a654b8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f64fd00 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 #4: ffff8880369b1128 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff8880369b1128 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1174 [inline] #4: ffff8880369b1128 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x870 drivers/base/dd.c:1372 #5: ffff888056d25258 (&devlink->lock_key#16){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x170 drivers/net/netdevsim/dev.c:1799 #6: ffffffff8e962eb8 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 4 locks held by syz-executor/29192: #0: ffff8880a1754ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:500 [inline] #0: ffff8880a1754ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x5a0 net/bluetooth/hci_core.c:2716 #1: ffff8880a17540b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x640/0x10e0 net/bluetooth/hci_sync.c:5356 #2: ffffffff8ff71020 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2151 [inline] #2: ffffffff8ff71020 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x260 net/bluetooth/hci_conn.c:2650 #3: ffff88807e39c2f8 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x92/0x570 net/bluetooth/l2cap_core.c:1777 2 locks held by syz-executor/29205: #0: ffffffff9033b4b0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff9033b4b0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff9033b4b0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4107 1 lock held by syz-executor/29206: #0: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4107 2 locks held by syz-executor/29216: #0: ffffffff90357fe8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff90357fe8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff90357fe8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4107 2 locks held by syz-executor/29218: #0: ffffffff9033b940 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff9033b940 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff9033b940 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4107 2 locks held by syz-executor/29222: #0: ffffffff9033b080 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff9033b080 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff9033b080 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8fde3540 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4107 ============================================= 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: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: 19127 Comm: kworker/u8:13 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:lock_is_held_type+0x10b/0x150 kernel/locking/lockdep.c:5945 Code: ff ff ff 65 0f c1 05 74 5d 88 07 83 f8 01 75 25 9c 58 a9 00 02 00 00 75 39 41 f7 c4 00 02 00 00 74 01 fb 89 d8 5b 41 5c 41 5d <41> 5e 41 5f 5d c3 cc cc cc cc cc 90 0f 0b 90 48 c7 c7 87 6f fd 8d RSP: 0000:ffffc90000006900 EFLAGS: 00000206 RAX: 0000000000000001 RBX: ffff8880785e0000 RCX: 0000000000000102 RDX: ffff888027c48000 RSI: ffffffff8e24d447 RDI: ffffffff8c289ce0 RBP: 00000000ffffffff R08: ffffffff89823c73 R09: ffffffff8e95cce0 R10: ffffc90000006fc0 R11: fffff52000000dff R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8e95cce0 R15: 0000000000000004 FS: 0000000000000000(0000) GS:ffff888125217000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7376ed2286 CR3: 000000000e74a000 CR4: 00000000003526f0 Call Trace: __skb_flow_dissect+0x52c/0x6d20 net/core/flow_dissector.c:1136 __xfrm_decode_session+0xf3/0xbb0 net/xfrm/xfrm_policy.c:3508 xfrm_decode_session include/net/xfrm.h:1337 [inline] ip_route_me_harder+0x9c0/0xf90 net/ipv4/netfilter.c:67 synproxy_send_tcp+0x34c/0x670 net/netfilter/nf_synproxy_core.c:432 synproxy_send_client_synack+0x8c1/0xe30 net/netfilter/nf_synproxy_core.c:485 nft_synproxy_eval_v4+0x34a/0x4e0 net/netfilter/nft_synproxy.c:60 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+0x467/0x19f0 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:6209 [inline] __netif_receive_skb net/core/dev.c:6322 [inline] process_backlog+0xaa3/0x1950 net/core/dev.c:6673 __napi_poll+0xae/0x340 net/core/dev.c:7737 napi_poll net/core/dev.c:7800 [inline] net_rx_action+0x627/0xf70 net/core/dev.c:7957 handle_softirqs+0x22a/0x840 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:891 [inline] nsim_dev_trap_report_work+0x7c7/0xb80 drivers/net/netdevsim/dev.c:922 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