rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=21697, q=2339 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10334 (4294960369-4294950035), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10335 jiffies! g21697 f0x2 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:27736 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x388/0x470 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: 5712 Comm: kworker/R-wg-cr Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: wg-crypt-wg2 wg_packet_encrypt_worker RIP: 0010:check_wait_context kernel/locking/lockdep.c:4889 [inline] RIP: 0010:__lock_acquire+0x58b/0x2cf0 kernel/locking/lockdep.c:5187 Code: b8 0e 48 c7 c6 95 16 35 8e 67 48 0f b9 3a 90 31 c9 0f b6 81 c4 00 00 00 84 c0 0f 84 77 ff ff ff 41 0f b6 f4 0f b6 d0 40 38 c6 <0f> 42 d6 80 b9 c6 00 00 00 02 0f 84 60 ff ff ff 89 d0 e9 59 ff ff RSP: 0018:ffffc900000069f8 EFLAGS: 00000046 RAX: 0000000000000003 RBX: ffff88807cbf4a10 RCX: ffffffff9414ca88 RDX: 0000000000000003 RSI: 0000000000000003 RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffff8176f21f R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8eb59c20 R12: 0000000000000003 R13: ffff88807cbf4a40 R14: ffff88807cbf3e00 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff888124f60000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb187f556b8 CR3: 0000000035e7e000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:840 [inline] class_rcu_constructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495 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:4612 [inline] slab_alloc_node mm/slub.c:4945 [inline] kmem_cache_alloc_noprof+0x2a0/0x5f0 mm/slub.c:4959 skb_ext_maybe_cow net/core/skbuff.c:7112 [inline] skb_ext_add+0x1b6/0x8e0 net/core/skbuff.c:7187 nf_bridge_unshare net/bridge/br_netfilter_hooks.c:170 [inline] br_nf_forward_ip+0xc3/0xa30 net/bridge/br_netfilter_hooks.c:686 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:280 [inline] NF_HOOK+0x23e/0x3f0 include/linux/netfilter.h:323 __br_forward+0x397/0x540 net/bridge/br_forward.c:115 deliver_clone net/bridge/br_forward.c:131 [inline] maybe_deliver net/bridge/br_forward.c:191 [inline] br_flood+0x3e6/0x8d0 net/bridge/br_forward.c:245 br_handle_frame_finish+0x1175/0x1990 net/bridge/br_input.c:229 br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x90c/0xc40 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:325 [inline] br_nf_pre_routing_ipv6+0x382/0x6f0 net/bridge/br_netfilter_ipv6.c:183 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0x127f/0x1510 net/bridge/br_input.c:442 __netif_receive_skb_core+0x989/0x30b0 net/core/dev.c:6093 __netif_receive_skb_one_core net/core/dev.c:6204 [inline] __netif_receive_skb net/core/dev.c:6319 [inline] process_backlog+0x706/0x1860 net/core/dev.c:6670 __napi_poll+0xaa/0x330 net/core/dev.c:7729 napi_poll net/core/dev.c:7792 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:7949 handle_softirqs+0x225/0x840 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:__crypto_xor+0x244/0xd10 lib/crypto/utils.c:42 Code: 2f 60 fd e9 08 ff ff ff e8 79 a9 f2 fc 4c 01 eb 48 83 c3 08 4f 8d 7c 2f 08 4d 01 ee 49 83 c6 08 8b 74 24 04 41 89 f4 45 29 ec 18 00 00 00 89 f5 e8 90 ad f2 fc 83 fd 18 73 0a e8 46 a9 f2 fc RSP: 0018:ffffc90004baf040 EFLAGS: 00000293 RAX: ffffffff84d3c677 RBX: ffffc90004baf480 RCX: ffff88807cbf3e00 RDX: 0000000000000000 RSI: 0000000000000018 RDI: 0000000000000018 RBP: 0000000000000018 R08: ffffc90004baefff R09: 0000000000000000 R10: ffffc90004baefc0 R11: fffff52000975e00 R12: 0000000000000020 R13: 0000000000000018 R14: ffffc90004baf0e0 R15: ffff88800bf96000 crypto_xor_cpy include/crypto/utils.h:52 [inline] chacha_crypt_generic lib/crypto/chacha.c:30 [inline] chacha_crypt_arch lib/crypto/x86/chacha.h:144 [inline] chacha_crypt+0xf24/0xf90 lib/crypto/chacha.c:44 chacha20_crypt include/crypto/chacha.h:94 [inline] chacha20poly1305_crypt_sg_inplace+0x4bf/0xea0 lib/crypto/chacha20poly1305.c:247 chacha20poly1305_encrypt_sg_inplace+0x3e/0x60 lib/crypto/chacha20poly1305.c:340 encrypt_packet drivers/net/wireguard/send.c:216 [inline] wg_packet_encrypt_worker+0x969/0x1760 drivers/net/wireguard/send.c:297 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 rescuer_thread+0x7b6/0x10b0 kernel/workqueue.c:3629 kthread+0x388/0x470 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 net_ratelimit: 6024 callbacks suppressed bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:42:1a:29:8c:56:ea, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:42:1a:29:8c:56:ea, vlan:0) net_ratelimit: 8596 callbacks suppressed bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:42:1a:29:8c:56:ea, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:42:1a:29:8c:56:ea, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)