rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P20066/1:b..l rcu: (detected by 0, t=10502 jiffies, g=62981, q=950688 ncpus=2) task:syz.1.4011 state:Z running task stack:25096 pid:20066 tgid:20066 ppid:16862 task_flags:0x40044c flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:rcu_is_watching+0x74/0xb0 kernel/rcu/tree.c:753 Code: 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 34 8b 03 65 ff 0d 49 e2 f9 10 74 11 83 e0 04 c1 e8 02 5b 41 5e 41 5f cc cc cc cc cc e8 31 69 8d ff eb e8 48 c7 c7 c0 fb 13 8e 48 89 RSP: 0018:ffffc9001290f9d8 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 52ffe613d4303f00 RDX: 0000000000000000 RSI: ffffffff8be333e0 RDI: ffffffff8be333a0 RBP: ffffffff822bc959 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffed1028095131 R12: 0000000000000002 R13: ffffffff8e139ee0 R14: 0000000000000000 R15: 0000000000000000 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x5f/0x360 kernel/locking/lockdep.c:5831 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] percpu_ref_put_many include/linux/percpu-refcount.h:330 [inline] percpu_ref_put+0x35/0x180 include/linux/percpu-refcount.h:351 memcg_kmem_uncharge_page include/linux/memcontrol.h:1728 [inline] exit_task_stack_account+0x226/0x340 kernel/fork.c:465 do_exit+0x1838/0x2300 kernel/exit.c:994 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 get_signal+0x1286/0x1340 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: 0033:0x7f8ed258ebe9 RSP: 002b:00007ffcfddd7cb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffff92 RBX: 0000000000063b07 RCX: 00007f8ed258ebe9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f8ed27b609c RBP: 0000000000000032 R08: 7fffffffffffffff R09: 00000006fddd7faf R10: 00007ffcfddd7db0 R11: 0000000000000246 R12: 00007f8ed27b609c R13: 00007ffcfddd7db0 R14: 0000000000063b39 R15: 00007ffcfddd7dd0 rcu: rcu_preempt kthread starved for 4184 jiffies! g62981 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:27160 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 18974 Comm: kworker/u8:92 Not tainted 6.17.0-rc1-syzkaller-00127-g715c7a36d59f #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: wg-kex-wg2 wg_packet_handshake_send_worker RIP: 0010:check_wait_context kernel/locking/lockdep.c:4868 [inline] RIP: 0010:__lock_acquire+0x446/0xd20 kernel/locking/lockdep.c:5187 Code: d3 44 0f b6 e9 44 0f 44 ea 44 8b a7 e8 0a 00 00 41 8d 4c 24 ff 83 f9 ff bd ff ff ff ff 0f 4c e9 ff c5 45 8d 7c 24 01 49 ff cc <44> 89 f9 83 c1 fe 78 44 44 89 e3 81 e3 ff ff ff 7f 83 f9 31 73 1d RSP: 0018:ffffc90000a07ea8 EFLAGS: 00000046 RAX: 00000000000c202e RBX: 0000000000000004 RCX: 00000000000e0029 RDX: 0000000000000002 RSI: 0000000000002000 RDI: ffff88804a7c3c00 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff84d03242 R10: dffffc0000000000 R11: ffffffff81a53600 R12: 0000000000000003 R13: 0000000000000002 R14: ffff88804a7c4808 R15: 0000000000000005 FS: 0000000000000000(0000) GS:ffff888125d1c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f18dc200218 CR3: 000000007d694000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 class_raw_spinlock_constructor include/linux/spinlock.h:535 [inline] pcpu_alloc+0x1d2/0x360 lib/debugobjects.c:281 alloc_object+0xbf/0x310 lib/debugobjects.c:458 lookup_object_or_alloc lib/debugobjects.c:685 [inline] debug_object_activate+0x183/0x420 lib/debugobjects.c:820 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline] __call_rcu_common kernel/rcu/tree.c:3108 [inline] call_rcu+0xaa/0x9c0 kernel/rcu/tree.c:3243 refdst_drop include/net/dst.h:263 [inline] skb_dst_drop include/net/dst.h:275 [inline] skb_release_head_state+0x71/0x250 net/core/skbuff.c:1135 skb_release_all net/core/skbuff.c:1149 [inline] __kfree_skb net/core/skbuff.c:1165 [inline] consume_skb+0x60/0xf0 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+0x409/0x1920 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:5979 [inline] __netif_receive_skb+0x143/0x380 net/core/dev.c:6092 process_backlog+0x60e/0x14f0 net/core/dev.c:6444 __napi_poll+0xc4/0x360 net/core/dev.c:7494 napi_poll net/core/dev.c:7557 [inline] net_rx_action+0x707/0xe30 net/core/dev.c:7684 handle_softirqs+0x283/0x870 kernel/softirq.c:579 do_softirq+0xec/0x180 kernel/softirq.c:480 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:407 local_bh_enable include/linux/bottom_half.h:33 [inline] fpregs_unlock arch/x86/include/asm/fpu/api.h:77 [inline] kernel_fpu_end+0xd2/0x120 arch/x86/kernel/fpu/core.c:479 blake2s_compress+0x5f/0xd0 lib/crypto/x86/blake2s-glue.c:46 blake2s_update+0x14b/0x450 lib/crypto/blake2s.c:33 mix_hash drivers/net/wireguard/noise.c:438 [inline] message_encrypt drivers/net/wireguard/noise.c:470 [inline] wg_noise_handshake_create_initiation+0x3f1/0x7e0 drivers/net/wireguard/noise.c:555 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:3236 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245