rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P19966/1:b..l rcu: (detected by 1, t=10503 jiffies, g=91705, q=2437 ncpus=2) task:syz.0.4519 state:R running task stack:25592 pid:19966 tgid:19966 ppid:18865 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x14f/0x760 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:unwind_next_frame+0x19f0/0x2550 arch/x86/kernel/unwind_orc.c:693 Code: 49 8d 56 40 4c 89 f7 4c 89 e6 e8 1b 0e 00 00 84 c0 0f 84 46 01 00 00 48 bd 00 00 00 00 00 fc ff df 48 8b 44 24 20 0f b6 04 28 <84> c0 0f 85 6a 08 00 00 b3 01 8b 84 24 8c 00 00 00 41 39 06 4c 8b RSP: 0018:ffffc9000d70f018 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffffffff90d3cbd8 RCX: 0000000000000001 RDX: ffffc9000d70f128 RSI: dffffc0000000000 RDI: ffffc9000d70f350 RBP: dffffc0000000000 R08: ffffc9000d70f350 R09: 0000000000000000 R10: ffffc9000d70f138 R11: fffff52001ae1e29 R12: ffffc9000d70f350 R13: 1ffff92001ae1e1f R14: ffffc9000d70f0e8 R15: 1ffffffff21a797b arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1402 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943 __slab_free+0x274/0x2c0 mm/slub.c:5612 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4905 mt_alloc_one lib/maple_tree.c:139 [inline] mas_alloc_nodes+0x291/0x350 lib/maple_tree.c:1089 mas_preallocate+0x2d6/0x640 lib/maple_tree.c:4961 vma_iter_prealloc mm/vma.h:577 [inline] __split_vma+0x318/0xa40 mm/vma.c:529 split_vma mm/vma.c:599 [inline] vma_modify+0x88a/0x1e10 mm/vma.c:1691 vma_modify_flags+0x24b/0x330 mm/vma.c:1719 mprotect_fixup+0x62a/0xb60 mm/mprotect.c:789 do_mprotect_pkey+0x8d5/0xd20 mm/mprotect.c:967 __do_sys_mprotect mm/mprotect.c:988 [inline] __se_sys_mprotect mm/mprotect.c:985 [inline] __x64_sys_mprotect+0x80/0x90 mm/mprotect.c:985 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f67ce99cc57 RSP: 002b:00007fffbe2b14c8 EFLAGS: 00000206 ORIG_RAX: 000000000000000a RAX: ffffffffffffffda RBX: 00007f67cf84f6c0 RCX: 00007f67ce99cc57 RDX: 0000000000000003 RSI: 0000000000020000 RDI: 00007f67cf830000 RBP: 0000000000000000 R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000021000 R11: 0000000000000206 R12: 00007fffbe2b1620 R13: ffffffffffffffc0 R14: 0000000000001000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 3181 jiffies! g91705 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 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:27536 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x389/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 12595 Comm: kworker/u8:12 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x1f/0x70 kernel/kcov.c:217 Code: 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 65 48 8b 0d 98 9b 73 11 65 8b 15 b9 9b 73 11 81 e2 00 01 ff 00 74 11 <81> fa 00 01 00 00 75 35 83 b9 d4 16 00 00 00 74 2c 8b 91 b0 16 00 RSP: 0018:ffffc90000006eb0 EFLAGS: 00000006 RAX: ffffffff81b27bb7 RBX: 0000000000000000 RCX: ffff888053219ec0 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000008 RBP: 0000000000000000 R08: ffffffff9030bff7 R09: 1ffffffff20617fe R10: dffffc0000000000 R11: fffffbfff20617ff R12: 0000000000000000 R13: 0000000000000000 R14: ffffc90000006f58 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88812528a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f116c000218 CR3: 000000007b3bc000 CR4: 00000000003526f0 Call Trace: __hrtimer_rearm_deferred+0x37/0x450 kernel/time/hrtimer.c:2045 hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:53 [inline] hrtimer_rearm_deferred include/linux/hrtimer_rearm.h:62 [inline] irqentry_exit_to_kernel_mode_after_preempt include/linux/irq-entry-common.h:513 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:550 [inline] irqentry_exit+0x6d5/0x760 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data kernel/kcov.c:246 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x2e/0x90 kernel/kcov.c:314 Code: 48 8b 04 24 65 48 8b 15 58 97 73 11 65 8b 0d 79 97 73 11 81 e1 00 01 ff 00 74 11 81 f9 00 01 00 00 75 5b 83 ba d4 16 00 00 00 <74> 52 8b 8a b0 16 00 00 83 f9 03 75 47 48 8b 8a b8 16 00 00 44 8b RSP: 0018:ffffc90000007008 EFLAGS: 00000246 RAX: ffffffff8a5222d1 RBX: 0000000000000140 RCX: 0000000000000100 RDX: ffff888053219ec0 RSI: 000000000000000e RDI: 0000000000000000 RBP: ffff88818f5b6e90 R08: 0aaaaaaaaaaa0000 R09: dd860aaaaaaaaaaa R10: 0aaaaaaaaaaa0000 R11: dd860aaaaaaaaaaa R12: dffffc0000000000 R13: 0000000000000010 R14: 000000000000000e R15: ffff88818f5b6e98 __skb_push include/linux/skbuff.h:2826 [inline] neigh_hh_output include/net/neighbour.h:543 [inline] neigh_output include/net/neighbour.h:558 [inline] ip6_finish_output2+0xce1/0x13e0 net/ipv6/ip6_output.c:136 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x340/0x550 net/ipv6/ip6_output.c:246 synproxy_send_tcp_ipv6+0x52f/0x6d0 net/netfilter/nf_synproxy_core.c:852 synproxy_send_client_synack_ipv6+0x814/0xcb0 net/netfilter/nf_synproxy_core.c:898 nft_synproxy_eval_v6+0x34a/0x4e0 net/netfilter/nft_synproxy.c:91 nft_synproxy_do_eval+0x3ce/0x580 net/netfilter/nft_synproxy.c:146 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x48d/0x1ae0 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x360/0x4b0 net/netfilter/nft_chain_filter.c:162 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316 ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:545 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6202 [inline] __netif_receive_skb net/core/dev.c:6315 [inline] process_backlog+0x7dd/0x1950 net/core/dev.c:6666 __napi_poll+0xae/0x340 net/core/dev.c:7733 napi_poll net/core/dev.c:7796 [inline] net_rx_action+0x627/0xf70 net/core/dev.c:7953 handle_softirqs+0x22a/0x840 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 blake2s_compress+0xf9/0x1eb0 lib/crypto/x86/blake2s.h:42 blake2s_final+0x116/0x270 lib/crypto/blake2s.c:142 hmac+0x2de/0x3b0 drivers/net/wireguard/noise.c:333 kdf+0x1a3/0x2b0 drivers/net/wireguard/noise.c:375 mix_dh drivers/net/wireguard/noise.c:413 [inline] wg_noise_handshake_create_initiation+0x2bc/0x830 drivers/net/wireguard/noise.c:550 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:34 [inline] wg_packet_handshake_send_worker+0x18d/0x350 drivers/net/wireguard/send.c:51 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x389/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245