INFO: task kworker/u8:1:13 blocked for more than 145 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:1 state:D stack:23672 pid:13 tgid:13 ppid:2 task_flags:0x4208160 flags:0x00080000 Workqueue: events_unbound linkwatch_event Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7f7/0x1550 kernel/locking/mutex.c:820 linkwatch_event+0xe/0x60 net/core/link_watch.c:313 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x389/0x470 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 INFO: task dhcpcd:5295 blocked for more than 148 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:dhcpcd state:D stack:21368 pid:5295 tgid:5295 ppid:5294 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7f7/0x1550 kernel/locking/mutex.c:820 rtnl_lock net/core/rtnetlink.c:80 [inline] rtnl_dumpit+0x92/0x200 net/core/rtnetlink.c:6865 netlink_dump+0x702/0xe10 net/netlink/af_netlink.c:2330 netlink_recvmsg+0x690/0xa50 net/netlink/af_netlink.c:1981 sock_recvmsg_nosec net/socket.c:1137 [inline] sock_recvmsg+0x172/0x1b0 net/socket.c:1159 ____sys_recvmsg+0x1e6/0x4a0 net/socket.c:2918 ___sys_recvmsg+0x215/0x590 net/socket.c:2960 __sys_recvmsg net/socket.c:2993 [inline] __do_sys_recvmsg net/socket.c:2999 [inline] __se_sys_recvmsg net/socket.c:2996 [inline] __x64_sys_recvmsg+0x1ba/0x2a0 net/socket.c:2996 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f65bad48407 RSP: 002b:00007ffd80473770 EFLAGS: 00000202 ORIG_RAX: 000000000000002f RAX: ffffffffffffffda RBX: 00007f65bacbe780 RCX: 00007f65bad48407 RDX: 0000000000000000 RSI: 00007ffd80473800 RDI: 000000000000001e RBP: 00007ffd804737e4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000001fd8 R13: 00007ffd804737f0 R14: 00007ffd804738e0 R15: 0000000000000000 Showing all locks held in the system: 3 locks held by kworker/u8:1/13: #0: ffff88801ae84140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88801ae84140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc90000127c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc90000127c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313 3 locks held by kworker/1:1/29: #0: ffff88813fe43140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88813fe43140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc90000a57c40 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc90000a57c40 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 1 lock held by khungtaskd/31: #0: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by kworker/u8:8/1028: #0: ffff88801ae84940 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] ffff88801ae84940 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffff8880b8624588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933 4 locks held by udevd/5000: 2 locks held by dhcpcd/5295: #0: ffff88807b8186e8 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: netlink_dump+0xe2/0xe10 net/netlink/af_netlink.c:2272 #1: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dumpit+0x92/0x200 net/core/rtnetlink.c:6865 2 locks held by getty/5400: #0: ffff888036a470a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0 drivers/tty/n_tty.c:2211 3 locks held by syz-executor/5623: 1 lock held by syz-executor/5650: #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3441 3 locks held by kworker/0:9/9393: #0: ffff88813fe43140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88813fe43140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc9000339fc40 (rx_mode_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc9000339fc40 (rx_mode_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: netdev_rx_mode_work+0x19/0x3c0 net/core/dev_addr_lists.c:1312 3 locks held by kworker/u8:19/9957: #0: ffff888032115140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff888032115140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc9000dcf7c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc9000dcf7c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x11e/0x14c0 net/ipv6/addrconf.c:4206 1 lock held by syz.4.2211/14207: #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3441 2 locks held by syz.2.2212/14208: #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3441 #1: ffffffff8e962fa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #1: ffffffff8e962fa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961 1 lock held by syz.1.2214/14216: #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3441 1 lock held by syz.0.2216/14224: #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3441 1 lock held by syz-executor/14236: #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 3 locks held by syz-executor/14244: #0: ffff888054e04ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:500 [inline] #0: ffff888054e04ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x5a0 net/bluetooth/hci_core.c:2679 #1: ffff888054e040b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x67c/0x1150 net/bluetooth/hci_sync.c:5366 #2: ffffffff8e962fa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #2: ffffffff8e962fa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961 1 lock held by syz-executor/14245: #0: ffff88803f2e4ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:500 [inline] #0: ffff88803f2e4ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x5a0 net/bluetooth/hci_core.c:2679 1 lock held by syz-executor/14247: #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 1 lock held by syz-executor/14253: #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 1 lock held by syz-executor/14282: #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fdc7e80 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 ============================================= 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 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+0x389/0x470 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 14245 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:arch_stack_walk+0x122/0x150 arch/x86/kernel/stacktrace.c:24 Code: 6b 09 00 48 85 c0 74 24 48 89 df 48 89 c6 4d 89 f3 2e 2e 2e 41 ff d3 84 c0 74 11 4c 89 ff e8 75 6c 09 00 83 bd 78 ff ff ff 00 <75> cf 65 48 8b 05 d4 aa ca 11 48 3b 45 d8 75 12 48 83 c4 68 5b 41 RSP: 0018:ffffc90000a07e68 EFLAGS: 00000202 RAX: 00000000916b8c01 RBX: ffffc90000a07f20 RCX: 0000000000000100 RDX: 0000000000000003 RSI: ffffffff8e215e66 RDI: ffff888027dc0000 RBP: ffffc90000a07ef0 R08: ffffc9000326ff38 R09: 0000000000000000 R10: ffffc90000a07eb8 R11: fffff52000140fd9 R12: ffff888027dc0000 R13: ffff88803cd61500 R14: ffffffff81b0e0e0 R15: ffffc90000a07e68 FS: 0000000000000000(0000) GS:ffff88812539e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5280c4fd86 CR3: 000000002521c000 CR4: 00000000003526f0 Call Trace: 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 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4570 [inline] slab_alloc_node mm/slub.c:4899 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4906 skb_clone+0x212/0x3a0 net/core/skbuff.c:2107 deliver_clone net/bridge/br_forward.c:125 [inline] br_flood+0x8cf/0xb80 net/bridge/br_forward.c:250 br_handle_frame_finish+0x1521/0x1c80 net/bridge/br_input.c:229 br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x91f/0xc30 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_pre_routing_ipv6+0x374/0x6f0 net/bridge/br_netfilter_ipv6.c:183 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0x1277/0x1510 net/bridge/br_input.c:442 __netif_receive_skb_core+0x98f/0x3170 net/core/dev.c:6089