INFO: task syz.5.4789:27650 blocked for more than 143 seconds. Tainted: G U syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.4789 state:D stack:28856 pid:27650 tgid:27649 ppid:22712 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7026 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x818/0x1060 kernel/locking/mutex.c:760 __tun_chr_ioctl+0x612/0x4880 drivers/net/tun.c:3078 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f75f498efc9 RSP: 002b:00007f75f582d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f75f4be5fa0 RCX: 00007f75f498efc9 RDX: 0000200000001080 RSI: 00000000400454cc RDI: 0000000000000003 RBP: 00007f75f4a11f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f75f4be6038 R14: 00007f75f4be5fa0 R15: 00007ffcfa5e7428 Showing all locks held in the system: 1 lock held by pool_workqueue_/3: #0: ffffffff8e3cf878 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343 1 lock held by khungtaskd/31: #0: ffffffff8e3c42e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e3c42e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e3c42e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 2 locks held by syz-executor/5819: #0: ffff8880752bde48 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x117/0x530 mm/mmap_lock.c:238 #1: ffff88814dd70518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x174/0x380 mm/memory.c:3488 2 locks held by kworker/0:5/5921: 3 locks held by kworker/u10:0/17546: 2 locks held by kworker/u10:3/17554: 3 locks held by kworker/u10:4/17575: 4 locks held by kworker/u10:5/17670: 3 locks held by kworker/u10:8/18927: 4 locks held by kworker/u10:9/19497: 4 locks held by kworker/u10:11/19502: 7 locks held by kworker/u10:13/19504: 3 locks held by kworker/0:1/21513: #0: ffff88813ff16948 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238 #1: ffffc9000d7dfd00 ( (reg_check_chans).work ){+.+.}-{0:0} , at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239 #2: ffffffff900e9f08 ( rtnl_mutex){+.+.}-{4:4}, at: reg_check_chans_work+0x91/0x11f0 net/wireless/reg.c:2453 4 locks held by kworker/0:3/24109: 3 locks held by kworker/u10:15/24615: 3 locks held by kworker/u10:17/24617: 3 locks held by kworker/u10:20/24623: 3 locks held by kworker/u10:21/24625: 3 locks held by kworker/u10:22/25376: 4 locks held by kworker/u10:23/25377: #0: ffff88801ba9f148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238 #1: ffffc9000d867d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239 #2: ffffffff900d3af0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x8b0 net/core/net_namespace.c:669 #3: ffffffff8e3cf878 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311 3 locks held by kworker/u10:24/25378: 3 locks held by kworker/u10:26/25381: 4 locks held by kworker/u10:27/25382: 3 locks held by kworker/u10:28/25383: 3 locks held by kworker/u10:29/25384: #0: ffff88814ccc5948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238 #1: ffffc9000e2a7d00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239 #2: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4734 3 locks held by kworker/u10:30/25385: 3 locks held by kworker/u10:31/25386: 3 locks held by kworker/u10:32/25387: 3 locks held by kworker/u10:33/25389: 3 locks held by kworker/u10:34/25391: 2 locks held by getty/26277: #0: ffff88803490a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900041672f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 1 lock held by syz-executor/26736: #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3436 3 locks held by kworker/0:4/26980: #0: ffff88813ff15948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238 #1: ffffc90003dffd00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239 #2: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 6 locks held by kworker/u11:3/27400: #0: ffff8880820ea148 ((wq_completion)hci2){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238 #1: ffffc9000b5e7d00 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239 #2: ffff888038668dc8 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x175/0x430 net/bluetooth/hci_sync.c:331 #3: ffff8880386680b8 (&hdev->lock){+.+.}-{4:4}, at: hci_abort_conn_sync+0x13f/0xb20 net/bluetooth/hci_sync.c:5679 #4: ffffffff9035dbc8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_connect_cfm include/net/bluetooth/hci_core.h:2103 [inline] #4: ffffffff9035dbc8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_failed+0x14f/0x330 net/bluetooth/hci_conn.c:1312 #5: ffff88807c30c338 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x80/0x730 net/bluetooth/l2cap_core.c:1762 1 lock held by syz.0.4778/27603: #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3436 3 locks held by syz.6.4788/27645: #0: ffffffff9018dad0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: nl80211_pre_doit+0xb4/0xb10 net/wireless/nl80211.c:17927 #2: ffff8880613f0788 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: wiphy_lock include/net/cfg80211.h:6343 [inline] #2: ffff8880613f0788 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: nl80211_pre_doit+0x71e/0xb10 net/wireless/nl80211.c:18000 1 lock held by syz.5.4789/27650: #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: __tun_chr_ioctl+0x612/0x4880 drivers/net/tun.c:3078 1 lock held by syz-executor/27661: #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:978 1 lock held by syz-executor/27670: #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:978 1 lock held by syz-executor/27673: #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:978 1 lock held by syz-executor/27675: #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:978 1 lock held by syz-executor/27689: #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:978 1 lock held by syz-executor/27695: #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:978 1 lock held by syz-executor/27699: #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:978 1 lock held by syz-executor/27701: #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff900e9f08 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:978 1 lock held by dhcpcd/27705: #0: ffff88807a99c260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline] #0: ffff88807a99c260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3197 1 lock held by dhcpcd/27706: #0: ffff888143378260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline] #0: ffff888143378260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3197 1 lock held by dhcpcd/27707: #0: ffff88814337a260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline] #0: ffff88814337a260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3197 1 lock held by dhcpcd/27708: #0: ffff888033398260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline] #0: ffff888033398260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3197 1 lock held by dhcpcd/27709: #0: ffff888144a9e260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline] #0: ffff888144a9e260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3197 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U syzkaller #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline] watchdog+0xf3f/0x1170 kernel/hung_task.c:495 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x675/0x7d0 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: 25376 Comm: kworker/u10:22 Tainted: G U syzkaller #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:__lock_acquire+0x10e/0x1c90 kernel/locking/lockdep.c:5141 Code: 9d 28 0b 00 00 83 fb 2f 76 09 45 84 e4 0f 85 31 0a 00 00 48 2d a0 c9 a7 95 49 89 c4 48 b8 29 5c 8f c2 f5 28 5c 8f 49 c1 fc 03 <4c> 89 e7 4c 8d a5 30 0b 00 00 48 0f af f8 89 d8 4c 8d 14 80 49 c1 RSP: 0018:ffffc90000006b10 EFLAGS: 00000006 RAX: 8f5c28f5c28f5c29 RBX: 0000000000000005 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e3c42e0 RBP: ffff88802744bc80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 00000000000000af R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff8e3c42e0 FS: 0000000000000000(0000) GS:ffff888124a10000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc362eb4a69 CR3: 000000000e182000 CR4: 00000000003526f0 Call Trace: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 __kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2539 [inline] slab_free mm/slub.c:6630 [inline] kmem_cache_free+0x2d4/0x6c0 mm/slub.c:6740 skb_kfree_head net/core/skbuff.c:1046 [inline] skb_kfree_head net/core/skbuff.c:1043 [inline] skb_free_head+0x1b7/0x210 net/core/skbuff.c:1060 skb_release_data+0x795/0x9e0 net/core/skbuff.c:1087 skb_release_all net/core/skbuff.c:1152 [inline] __kfree_skb net/core/skbuff.c:1166 [inline] consume_skb net/core/skbuff.c:1398 [inline] consume_skb+0xbf/0x100 net/core/skbuff.c:1392 netlink_broadcast_filtered+0x3ee/0xf90 net/netlink/af_netlink.c:1537 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] nlmsg_notify+0x9e/0x220 net/netlink/af_netlink.c:2595 fdb_notify+0xfd/0x1a0 net/bridge/br_fdb.c:199 br_fdb_update+0x323/0x7c0 net/bridge/br_fdb.c:1036 br_handle_frame_finish+0xdc0/0x1ec0 net/bridge/br_input.c:144 br_nf_hook_thresh+0x307/0x410 net/bridge/br_netfilter_hooks.c:1167 br_nf_pre_routing_finish_ipv6+0x76a/0xfc0 net/bridge/br_netfilter_ipv6.c:154 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_pre_routing_ipv6+0x3cd/0x8c0 net/bridge/br_netfilter_ipv6.c:184 br_nf_pre_routing+0x860/0x15b0 net/bridge/br_netfilter_hooks.c:508 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0xad8/0x14b0 net/bridge/br_input.c:442 __netif_receive_skb_core.constprop.0+0xa25/0x4bd0 net/core/dev.c:5966 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6077 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6192 process_backlog+0x439/0x15e0 net/core/dev.c:6544 __napi_poll.constprop.0+0xba/0x550 net/core/dev.c:7594 napi_poll net/core/dev.c:7657 [inline] net_rx_action+0x97f/0xef0 net/core/dev.c:7784 handle_softirqs+0x219/0x8e0 kernel/softirq.c:622 do_softirq kernel/softirq.c:523 [inline] do_softirq+0xb2/0xf0 kernel/softirq.c:510 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:835 [inline] nsim_dev_trap_report_work+0x8b5/0xcf0 drivers/net/netdevsim/dev.c:866 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263 process_scheduled_works kernel/workqueue.c:3346 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 net_ratelimit: 8294 callbacks suppressed bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:d2:e2:7e:7e:43:c0, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:d2:e2:7e:7e:43:c0, vlan:0)