INFO: task syz.3.3404:19575 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.3.3404 state:D stack:25688 pid:19575 tgid:19575 ppid:18228 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75 down_write_failed drivers/tty/tty_ldsem.c:262 [inline] __ldsem_down_write_nested+0x304/0x730 drivers/tty/tty_ldsem.c:324 __tty_ldisc_lock drivers/tty/tty_ldisc.c:289 [inline] tty_ldisc_lock_pair_timeout drivers/tty/tty_ldisc.c:352 [inline] tty_ldisc_lock_pair drivers/tty/tty_ldisc.c:366 [inline] tty_ldisc_release+0x110/0x200 drivers/tty/tty_ldisc.c:780 tty_release_struct+0x2a/0xd0 drivers/tty/tty_io.c:1681 tty_release+0xcb0/0x1720 drivers/tty/tty_io.c:1852 __fput+0x44c/0xa70 fs/file_table.c:468 task_work_run+0x1d4/0x260 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:44 [inline] exit_to_user_mode_loop+0xef/0x4e0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8dedf8f749 RSP: 002b:00007f8dee30fb88 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f8dee1e7da0 RCX: 00007f8dedf8f749 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f8dee1e7da0 R08: 00000000000000e0 R09: 0000000cee30fe7f R10: 00000000003ffcf8 R11: 0000000000000246 R12: 00000000000f9a2b R13: 00007f8dee1e6090 R14: ffffffffffffffff R15: 00007f8dee30fca0 Showing all locks held in the system: 1 lock held by kthreadd/2: 2 locks held by kworker/0:1/10: 4 locks held by kworker/u8:0/12: 1 lock held by khungtaskd/31: #0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:2/36: 3 locks held by kworker/u8:3/50: 4 locks held by kworker/u8:4/60: 4 locks held by kworker/u8:5/70: 3 locks held by kworker/1:2/130: 4 locks held by kworker/u8:10/3489: 4 locks held by kworker/u8:11/3504: 3 locks held by kworker/u8:12/3573: #0: ffff88814ca09148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88814ca09148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc9000cdb7bc0 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9000cdb7bc0 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 #2: ffffffff8f311e48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f311e48 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x19/0x30 net/ipv6/addrconf.c:4734 3 locks held by kworker/u8:13/3866: 8 locks held by kworker/u8:14/3878: 2 locks held by klogd/5189: 3 locks held by udevd/5200: 1 lock held by dhcpcd/5494: 1 lock held by crond/5569: 2 locks held by getty/5586: #0: ffff88803549d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460 drivers/tty/n_tty.c:2211 3 locks held by kworker/1:4/5883: 2 locks held by kworker/0:3/5890: 2 locks held by kworker/0:6/5915: 3 locks held by kworker/1:7/5934: 2 locks held by kworker/1:8/5945: 3 locks held by kworker/1:10/5981: 4 locks held by kworker/u8:15/5982: 3 locks held by kworker/u8:17/6029: 2 locks held by kworker/u8:19/6400: 3 locks held by kworker/u8:20/6927: 4 locks held by kworker/u8:21/7257: 4 locks held by kworker/u8:22/7799: 4 locks held by kworker/1:0/17265: 2 locks held by syz-executor/17292: 4 locks held by kworker/1:3/17557: 1 lock held by syz-executor/17994: #0: ffff888030190308 (&xt[i].mutex){+.+.}-{4:4}, at: xt_find_table_lock+0x54/0x3e0 net/netfilter/x_tables.c:1243 3 locks held by kworker/u8:6/18409: 4 locks held by kworker/u8:7/18504: 2 locks held by kworker/u8:8/18868: 1 lock held by syz.5.3399/19564: 1 lock held by syz.4.3405/19579: 1 lock held by syz.3.3404/19575: #0: ffff8880349070a0 (&tty->ldisc_sem){++++}-{0:0}, at: __tty_ldisc_lock drivers/tty/tty_ldisc.c:289 [inline] #0: ffff8880349070a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_lock_pair_timeout drivers/tty/tty_ldisc.c:352 [inline] #0: ffff8880349070a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_lock_pair drivers/tty/tty_ldisc.c:366 [inline] #0: ffff8880349070a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_release+0x110/0x200 drivers/tty/tty_ldisc.c:780 3 locks held by kworker/1:5/19584: 2 locks held by kworker/u8:9/19586: 2 locks held by kworker/1:6/19587: 3 locks held by kworker/0:9/19589: 4 locks held by kworker/u8:16/19590: 4 locks held by syz-executor/19591: ============================================= NMI backtrace for cpu 0 CPU: 0 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 10/25/2025 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:160 [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:346 [inline] watchdog+0xf95/0xfe0 kernel/hung_task.c:515 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 18504 Comm: kworker/u8:7 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [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:is_pppoe_ip net/bridge/br_netfilter_hooks.c:124 [inline] RIP: 0010:br_nf_forward+0x2a8/0x18d0 net/bridge/br_netfilter_hooks.c:769 Code: 89 f7 e8 3b a9 ee f7 49 8b 3e 8b 35 4a 9b 4b 05 e8 fd c9 ff ff 49 89 c7 48 8b 44 24 18 42 0f b6 04 20 84 c0 0f 85 13 10 00 00 <44> 0f b7 33 bf 88 64 00 00 44 89 f6 e8 27 8a 88 f7 41 81 fe 88 64 RSP: 0018:ffffc90000a08078 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888096d38974 RCX: 0000000000000101 RDX: 0000000000000006 RSI: ffffffff8d976a7d RDI: ffff888025285b80 RBP: ffff88805887b080 R08: ffffffff8a383bae R09: ffffffff8df41aa0 R10: 0000000000000003 R11: ffffffff8a386f00 R12: dffffc0000000000 R13: ffff888096d388c0 R14: ffffc90000a081e0 R15: ffff88805887b080 FS: 0000000000000000(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000025a030 CR3: 000000000dd3a000 CR4: 00000000003526f0 Call Trace: nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x215/0x3c0 include/linux/netfilter.h:316 __br_forward+0x397/0x540 net/bridge/br_forward.c:115 deliver_clone net/bridge/br_forward.c:131 [inline] maybe_deliver+0xb5/0x160 net/bridge/br_forward.c:191 br_flood+0x31a/0x6a0 net/bridge/br_forward.c:238 br_handle_frame_finish+0x15a3/0x1c90 net/bridge/br_input.c:229 br_nf_hook_thresh+0x3c6/0x4a0 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x999/0xd60 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_pre_routing_ipv6+0x37e/0x6b0 net/bridge/br_netfilter_ipv6.c:184 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0x96e/0x14f0 net/bridge/br_input.c:442 __netif_receive_skb_core+0x95f/0x2f90 net/core/dev.c:6026 __netif_receive_skb_one_core net/core/dev.c:6137 [inline] __netif_receive_skb+0x72/0x380 net/core/dev.c:6252 process_backlog+0x54f/0x1340 net/core/dev.c:6604 __napi_poll+0xae/0x320 net/core/dev.c:7668 napi_poll net/core/dev.c:7731 [inline] net_rx_action+0x64a/0xe00 net/core/dev.c:7883 handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 blake2s_compress+0xe0/0x1e30 lib/crypto/x86/blake2s.h:42 blake2s_final+0x116/0x270 lib/crypto/blake2s.c:142 hmac+0x293/0x330 drivers/net/wireguard/noise.c:333 kdf+0x105/0x270 drivers/net/wireguard/noise.c:367 mix_dh drivers/net/wireguard/noise.c:413 [inline] wg_noise_handshake_create_initiation+0x278/0x750 drivers/net/wireguard/noise.c:550 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:34 [inline] wg_packet_handshake_send_worker+0x163/0x320 drivers/net/wireguard/send.c:51 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246