INFO: task syz.6.3298:22200 blocked for more than 145 seconds. Tainted: G U L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.6.3298 state:D stack:29000 pid:22200 tgid:22199 ppid:19837 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0xc69/0x1ca0 kernel/locking/mutex.c:776 rtnl_net_lock include/linux/rtnetlink.h:130 [inline] register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2083 ops_init+0x1e2/0x5f0 net/core/net_namespace.c:137 setup_net+0x11d/0x3a0 net/core/net_namespace.c:446 copy_net_ns+0x351/0x7c0 net/core/net_namespace.c:581 create_new_namespaces+0x3ea/0xab0 kernel/nsproxy.c:130 unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x45b/0xa40 kernel/fork.c:3171 __do_sys_unshare kernel/fork.c:3242 [inline] __se_sys_unshare kernel/fork.c:3240 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3240 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd5ca38f7c9 RSP: 002b:00007fd5cb20a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007fd5ca5e5fa0 RCX: 00007fd5ca38f7c9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000080 RBP: 00007fd5ca413f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd5ca5e6038 R14: 00007fd5ca5e5fa0 R15: 00007ffffcbcfb58 INFO: task syz.6.3298:22204 blocked for more than 145 seconds. Tainted: G U L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.6.3298 state:D stack:27992 pid:22204 tgid:22199 ppid:19837 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0xc69/0x1ca0 kernel/locking/mutex.c:776 rtnl_lock net/core/rtnetlink.c:80 [inline] rtnetlink_rcv_msg+0x371/0xe90 net/core/rtnetlink.c:6964 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646 __sys_sendmmsg+0x200/0x420 net/socket.c:2735 __do_sys_sendmmsg net/socket.c:2762 [inline] __se_sys_sendmmsg net/socket.c:2759 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2759 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd5ca38f7c9 RSP: 002b:00007fd5cb1c8038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007fd5ca5e6180 RCX: 00007fd5ca38f7c9 RDX: 0000000000000007 RSI: 0000200000000200 RDI: 0000000000000006 RBP: 00007fd5ca413f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd5ca5e6218 R14: 00007fd5ca5e6180 R15: 00007ffffcbcfb58 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e3c9520 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e3c9520 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e3c9520 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 1 lock held by khugepaged/39: #0: ffffffff8e5066c8 (lock#5){+.+.}-{4:4}, at: __lru_add_drain_all+0x6e/0x6f0 mm/swap.c:840 2 locks held by getty/5593: #0: ffff88814eb980a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x1510 drivers/tty/n_tty.c:2211 2 locks held by syz-executor/5821: #0: ffff8880315ed088 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x117/0x580 mm/mmap_lock.c:259 #1: ffff88814ebcc518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x174/0x380 mm/memory.c:3528 2 locks held by kworker/0:3/5828: 3 locks held by kworker/1:4/5889: #0: ffff88813ff55948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232 #1: ffffc900042bfc90 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233 #2: ffffffff8e3d4c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343 3 locks held by kworker/0:5/5924: 4 locks held by kworker/u10:0/9161: 2 locks held by kworker/u10:5/9173: 2 locks held by kworker/u10:8/9182: 3 locks held by kworker/u10:9/9197: 3 locks held by kworker/u10:11/9215: 3 locks held by kworker/u10:14/9392: 3 locks held by kworker/u10:17/9780: 6 locks held by kworker/u10:19/13915: #0: ffff888141af7148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232 #1: ffffc90003157c90 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233 #2: ffff88814ebcc0e0 (&type->s_umount_key#32){++++}-{4:4}, at: super_trylock_shared+0x1e/0xf0 fs/super.c:563 #3: ffff88814ebceb98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x27a/0x600 mm/page-writeback.c:2598 #4: ffff88814ebd0950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x5e7/0x1410 fs/jbd2/transaction.c:444 #5: ffff888076ee15b0 (&ei->i_data_sem){++++}-{4:4}, at: ext4_map_blocks+0x475/0x1350 fs/ext4/inode.c:815 3 locks held by kworker/u10:20/13916: 4 locks held by kworker/u10:22/13918: 4 locks held by kworker/u10:25/13921: 3 locks held by kworker/u10:30/13931: 3 locks held by kworker/u10:36/13938: 3 locks held by kworker/u10:41/13945: 7 locks held by kworker/u10:42/13946: 3 locks held by kworker/u10:44/17419: 4 locks held by kworker/u10:48/17423: 3 locks held by kworker/u10:49/17424: 3 locks held by kworker/u10:50/17425: #0: ffff88802fc06948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232 #1: ffffc900036a7c90 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233 #2: ffffffff90145528 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff90145528 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4734 4 locks held by kworker/u10:52/17427: 4 locks held by kworker/u10:55/17686: 3 locks held by kworker/u10:56/17687: 3 locks held by kworker/u10:57/17690: 4 locks held by kworker/u10:59/17901: 3 locks held by kworker/u10:60/17902: 3 locks held by kworker/u10:61/19438: 4 locks held by kworker/u10:62/19439: 2 locks held by syz.6.3298/22200: #0: ffffffff9012ed50 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x333/0x7c0 net/core/net_namespace.c:577 #1: ffffffff90145528 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff90145528 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2083 1 lock held by syz.6.3298/22204: #0: ffffffff90145528 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff90145528 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x371/0xe90 net/core/rtnetlink.c:6964 4 locks held by kworker/1:5/22222: #0: ffff88807f368948 ((wq_completion)wg-kex-wg0#9){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232 #1: ffffc90010847c90 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __asm__ ("" : "=r"(__ptr) : "0"((__typeof__(*((worker))) *)(( unsigned long)((worker))))); (typeof((__typeof__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233 #2: ffff8880126f9308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_consume_initiation+0x1c2/0x880 drivers/net/wireguard/noise.c:598 #3: ffff88803168b4c0 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_consume_initiation+0x5ac/0x880 drivers/net/wireguard/noise.c:632 2 locks held by syz-executor/22230: #0: ffff88814ebcc420 (sb_writers#4){.+.+}-{0:0}, at: filename_create+0x10d/0x400 fs/namei.c:4872 #1: ffff888076dfb400 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1072 [inline] #1: ffff888076dfb400 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2864 [inline] #1: ffff888076dfb400 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2875 [inline] #1: ffff888076dfb400 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_create+0x1c0/0x400 fs/namei.c:4879 2 locks held by syz-executor/22231: #0: ffff88814ebcc420 (sb_writers#4){.+.+}-{0:0}, at: filename_create+0x10d/0x400 fs/namei.c:4872 #1: ffff888076dfb400 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1072 [inline] #1: ffff888076dfb400 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2864 [inline] #1: ffff888076dfb400 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2875 [inline] #1: ffff888076dfb400 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_create+0x1c0/0x400 fs/namei.c:4879 2 locks held by dhcpcd/22233: #0: ffff88802bf32260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1700 [inline] #0: ffff88802bf32260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3197 #1: ffffffff8e3d4c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343 1 lock held by dhcpcd/22234: #0: ffff88802d24a260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1700 [inline] #0: ffff88802d24a260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3197 1 lock held by dhcpcd/22235: #0: ffff88806dba0260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1700 [inline] #0: ffff88806dba0260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3197 1 lock held by dhcpcd/22236: #0: ffff888029f9c260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1700 [inline] #0: ffff888029f9c260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3197 1 lock held by dhcpcd/22237: #0: ffff888029f98260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1700 [inline] #0: ffff888029f98260 (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 L syzkaller #0 PREEMPT(full) Tainted: [U]=USER, [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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] __sys_info lib/sys_info.c:157 [inline] sys_info+0x133/0x180 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xe66/0x1180 kernel/hung_task.c:515 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 17421 Comm: kworker/u10:46 Tainted: G U L syzkaller #0 PREEMPT(full) Tainted: [U]=USER, [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: wg-kex-wg2 wg_packet_handshake_send_worker RIP: 0010:mark_lock+0x1/0x9f0 kernel/locking/lockdep.c:4714 Code: fe ff ff 4c 89 f6 48 c7 c7 00 79 2c 8e e8 b7 ec 45 03 e9 56 fd ff ff 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 <48> 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 f0 48 83 ec 70 65 48 RSP: 0018:ffffc90000007498 EFLAGS: 00000046 RAX: 0000000000000003 RBX: 0000000000000005 RCX: ffffffff95b91fd8 RDX: 0000000000000008 RSI: ffff8880385348f8 RDI: ffff888038533d00 RBP: 0000000000000005 R08: 0000000000000000 R09: 0000000000000007 R10: 0000000000000002 R11: ffff888038534830 R12: ffff888038533d00 R13: 0000000000000001 R14: ffff8880385348f8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881248fc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32310ff8 CR3: 000000000e184000 CR4: 00000000003526f0 Call Trace: mark_usage kernel/locking/lockdep.c:4674 [inline] __lock_acquire+0x436/0x2890 kernel/locking/lockdep.c:5191 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 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+0xd1/0x20b0 arch/x86/kernel/unwind_orc.c:495 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:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6670 [inline] kmem_cache_free+0x2d8/0x770 mm/slub.c:6781 kfree_skbmem+0x1a4/0x1f0 net/core/skbuff.c:1130 __kfree_skb net/core/skbuff.c:1197 [inline] sk_skb_reason_drop+0x136/0x1a0 net/core/skbuff.c:1234 kfree_skb_reason include/linux/skbuff.h:1322 [inline] kfree_skb include/linux/skbuff.h:1331 [inline] ip6_mc_input+0x82c/0xf60 net/ipv6/ip6_input.c:593 dst_input include/net/dst.h:474 [inline] dst_input include/net/dst.h:472 [inline] ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline] NF_HOOK include/linux/netfilter.h:318 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] ipv6_rcv+0x497/0x650 net/ipv6/ip6_input.c:311 __netif_receive_skb_one_core+0x12d/0x1e0 net/core/dev.c:6139 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6252 process_backlog+0x4a2/0x1650 net/core/dev.c:6604 __napi_poll.constprop.0+0xb3/0x540 net/core/dev.c:7668 napi_poll net/core/dev.c:7731 [inline] net_rx_action+0x9f9/0xfa0 net/core/dev.c:7883 handle_softirqs+0x219/0x950 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 local_bh_enable include/linux/bottom_half.h:33 [inline] fpregs_unlock arch/x86/include/asm/fpu/api.h:77 [inline] kernel_fpu_end arch/x86/kernel/fpu/core.c:480 [inline] kernel_fpu_end+0x5e/0x70 arch/x86/kernel/fpu/core.c:473 blake2s_compress+0x77/0xe0 lib/crypto/x86/blake2s.h:42 blake2s_final+0xc9/0x160 lib/crypto/blake2s.c:142 mix_hash+0xfa/0x140 drivers/net/wireguard/noise.c:439 message_ephemeral+0x46/0x70 drivers/net/wireguard/noise.c:492 wg_noise_handshake_create_initiation+0x322/0x610 drivers/net/wireguard/noise.c:545 wg_packet_send_handshake_initiation+0x19a/0x360 drivers/net/wireguard/send.c:34 wg_packet_handshake_send_worker+0x1c/0x30 drivers/net/wireguard/send.c:51 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 net_ratelimit: 10180 callbacks suppressed bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)