rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5649/1:b..l rcu: (detected by 1, t=10503 jiffies, g=34429, q=1916 ncpus=2) task:syz-executor state:R running task stack:22384 pid:5649 tgid:5649 ppid:5628 task_flags:0x400140 flags:0x00080000 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:539 [inline] irqentry_exit+0x14f/0x8b0 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 31 af 05 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 0b 9a 96 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 18 e2 91 RSP: 0018:ffffc90003c9f298 EFLAGS: 00000282 RAX: c33a9046f1ce0100 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 000000000973479e RSI: ffffffff8e2168c0 RDI: ffffffff8c28b760 RBP: ffffffff8176e256 R08: ffffffff8176e256 R09: ffffffff8e95cc20 R10: ffffc90003c9f458 R11: fffff52000793e8d R12: 0000000000000002 R13: ffffffff8e95cc20 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0xc3/0x2550 arch/x86/kernel/unwind_orc.c:495 __unwind_start+0x5b8/0x760 arch/x86/kernel/unwind_orc.c:787 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24 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:1397 [inline] __free_frozen_pages+0xc1c/0xd30 mm/page_alloc.c:2938 __slab_free+0x274/0x2c0 mm/slub.c:5613 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:4570 [inline] slab_alloc_node mm/slub.c:4899 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4906 lsm_file_alloc security/security.c:171 [inline] security_file_alloc+0x34/0x310 security/security.c:2406 init_file+0x90/0x2b0 fs/file_table.c:184 alloc_empty_file+0x74/0x1d0 fs/file_table.c:266 path_openat+0x10f/0x3860 fs/namei.c:4844 do_file_open+0x23e/0x4a0 fs/namei.c:4887 do_sys_openat2+0x113/0x200 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1381 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5b5099c17c RSP: 002b:00007f5b50d3fd40 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000143 RCX: 00007f5b5099c17c RDX: 0000000000090800 RSI: 00007f5b50a326b1 RDI: 00000000ffffff9c RBP: 00007f5b50d3fdec R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000064 R13: 0000000000000000 R14: 000000000002b9b2 R15: 00007f5b50d3fe40 rcu: rcu_preempt kthread starved for 2285 jiffies! g34429 f0x0 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:27968 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: CPU: 1 UID: 0 PID: 5683 Comm: kworker/R-wg-cr Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: wg-crypt-wg1 wg_packet_decrypt_worker RIP: 0010:deref_stack_reg+0x1cf/0x230 arch/x86/kernel/unwind_orc.c:424 Code: 24 18 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 23 02 ba 00 4c 89 33 b0 01 eb 02 31 c0 48 83 c4 20 5b 41 5c 41 5d <41> 5e 41 5f 5d c3 cc cc cc cc cc 44 89 f9 80 e1 07 80 c1 03 38 c1 RSP: 0018:ffffc90000a07d58 EFLAGS: 00000282 RAX: 1ffff92000140f01 RBX: ffffffff9150051c RCX: 0000000000000001 RDX: ffffc90000a07e88 RSI: dffffc0000000000 RDI: ffffc90000a083d0 RBP: 1ffff92000140fc9 R08: ffffc90000a083d0 R09: 0000000000000000 R10: ffffc90000a07e98 R11: fffff52000140fd5 R12: ffffc90000a083d0 R13: 1ffff92000140fcb R14: ffffc90000a084b0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff88812539c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7bad2ce6df CR3: 0000000074cf0000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 08c5d32ffc85c5bc DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: unwind_next_frame+0x19d5/0x2550 arch/x86/kernel/unwind_orc.c:-1 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4570 [inline] slab_alloc_node mm/slub.c:4899 [inline] kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4951 __alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702 alloc_skb include/linux/skbuff.h:1385 [inline] synproxy_send_client_synack+0x172/0xe30 net/netfilter/nf_synproxy_core.c:463 nft_synproxy_eval_v4+0x34a/0x4e0 net/netfilter/nft_synproxy.c:60 nft_synproxy_do_eval+0x305/0x580 net/netfilter/nft_synproxy.c:142 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 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+0xaa3/0x1950 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 spin_unlock_bh include/linux/spinlock.h:396 [inline] ptr_ring_consume_bh include/linux/ptr_ring.h:377 [inline] wg_packet_decrypt_worker+0xd01/0xd80 drivers/net/wireguard/receive.c:499 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 rescuer_thread+0x827/0x1130 kernel/workqueue.c:3621 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