INFO: task syz.1.723:9729 blocked for more than 143 seconds. Not tainted syzkaller #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.723 state:D stack:25608 pid:9729 tgid:9729 ppid:5844 task_flags:0x40044c flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common kernel/sched/completion.c:121 [inline] wait_for_common kernel/sched/completion.c:132 [inline] wait_for_completion+0x2bf/0x5d0 kernel/sched/completion.c:153 rcu_barrier+0x463/0x570 kernel/rcu/tree.c:3883 netdev_run_todo+0x327/0xea0 net/core/dev.c:11477 tun_detach drivers/net/tun.c:640 [inline] tun_chr_close+0x13f/0x1c0 drivers/net/tun.c:3436 __fput+0x45b/0xa80 fs/file_table.c:468 task_work_run+0x1d1/0x260 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x6b5/0x2300 kernel/exit.c:961 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 get_signal+0x125e/0x1310 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 00fb:0x294e66b3c7c44cb4 RSP: 002b:0000000000000000 EFLAGS: 00000202 ORIG_RAX: ce3d5c200518e753 RAX: 6d02b596a6d6b2c6 RBX: 46b00e13ac8c17fa RCX: 1d6d567492f1521e RDX: eb30e365dd53f3a0 RSI: c553273f825e1cf7 RDI: b331ef28487276fd RBP: 9c8c87e20081ee76 R08: cf9d780a350b4549 R09: c7e58b697db8ef3d R10: d68d02d45a22dc24 R11: 19b4d49ef33da9ed R12: 39cb75b6fa6cb3d1 R10: d68d02d45a22dc24 R11: 19b4d49ef33da9ed R12: 39cb75b6fa6cb3d1 R13: a8d7b5dbf29d588f R14: 9b8908dcbb4f02b4 R15: 107b9d1451766018 Showing all locks held in the system: 3 locks held by rcuc/1/28: 1 lock held by khungtaskd/39: #0: ffffffff8d9a8dc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8d9a8dc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8d9a8dc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:10/3513: #0: ffff88802faef938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88802faef938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc9000d717bc0 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc9000d717bc0 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x19/0x30 net/ipv6/addrconf.c:4734 2 locks held by getty/5600: #0: ffff88823bf7c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e7e2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1410 drivers/tty/n_tty.c:2222 1 lock held by syz.1.723/9729: #0: ffffffff8d9ae770 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3815 3 locks held by kworker/0:0/10639: #0: ffff888019898538 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff888019898538 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc90004567bc0 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc90004567bc0 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 3 locks held by kworker/u8:0/11414: #0: ffff888019881138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff888019881138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc90003f07bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc90003f07bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 1 lock held by syz.7.1331/12768: #0: ffffffff8d9ae770 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3815 1 lock held by syz-executor/13643: #0: ffffffff8d9ae770 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3815 1 lock held by syz-executor/13665: #0: ffffffff8d9ae770 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3815 1 lock held by syz.5.1948/14774: #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x41/0x1c0 drivers/net/tun.c:3436 1 lock held by syz-executor/14821: #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x41/0x1c0 drivers/net/tun.c:3436 2 locks held by syz-executor/14823: #0: ffffffff8ecc69a0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x304/0x4d0 net/core/net_namespace.c:566 #1: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: wg_netns_pre_exit+0x1c/0x1d0 drivers/net/wireguard/device.c:417 1 lock held by syz-executor/14858: #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/14870: #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/14877: #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/14879: #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/14881: #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/14891: #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/14896: #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/14901: #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/14903: #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/14905: #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/14921: #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8ecd38b8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 39 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0xf93/0xfe0 kernel/hung_task.c:491 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 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: 28 Comm: rcuc/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline] RIP: 0010:lock_acquire+0x58/0x360 kernel/locking/lockdep.c:5831 Code: 8b 05 ec 3f 5a 10 48 89 44 24 58 0f 1f 44 00 00 65 8b 05 ef 3f 5a 10 83 f8 08 0f 83 b8 01 00 00 89 c0 48 0f a3 05 d8 61 81 0d <73> 16 e8 c1 14 09 00 84 c0 75 0d f6 05 d5 6a 6b 0d 01 0f 84 d7 01 RSP: 0018:ffffc90000a2e698 EFLAGS: 00000297 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8d9a8dc0 RBP: ffffffff8172c165 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc90000a2e858 R11: ffffffff81aaf080 R12: 0000000000000002 R13: ffffffff8d9a8dc0 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881269bc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f157dcf35f0 CR3: 00000000358ba000 CR4: 00000000003526f0 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2422 [inline] slab_free mm/slub.c:4695 [inline] kmem_cache_free+0x195/0x510 mm/slub.c:4797 skb_release_data+0x62d/0x7c0 net/core/skbuff.c:1086 skb_release_all net/core/skbuff.c:1151 [inline] __kfree_skb net/core/skbuff.c:1165 [inline] consume_skb+0x9e/0xf0 net/core/skbuff.c:1397 nft_synproxy_eval_v4+0x376/0x560 net/netfilter/nft_synproxy.c:60 nft_synproxy_do_eval+0x345/0x570 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x40c/0x1920 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x25d/0x340 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc2/0x220 net/netfilter/core.c:623 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:316 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:5991 [inline] __netif_receive_skb+0x143/0x380 net/core/dev.c:6104 process_backlog+0x31e/0x900 net/core/dev.c:6456 __napi_poll+0xb3/0x540 net/core/dev.c:7506 napi_poll net/core/dev.c:7569 [inline] net_rx_action+0x707/0xe00 net/core/dev.c:7696 handle_softirqs+0x22c/0x710 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] __local_bh_enable_ip+0x179/0x270 kernel/softirq.c:259 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_do_batch kernel/rcu/tree.c:2624 [inline] rcu_core kernel/rcu/tree.c:2861 [inline] rcu_cpu_kthread+0xc3d/0x1b50 kernel/rcu/tree.c:2949 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245