IPVS: wrr: UDP 224.0.0.2:0 - no destination available IPVS: wrr: UDP 224.0.0.2:0 - no destination available rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P22750/1:b..l P23774/1:b..l rcu: (detected by 0, t=10540 jiffies, g=409745, q=1328 ncpus=2) task:kworker/u8:7 state:R running task stack:19464 pid:23774 tgid:23774 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: krds_cp_wq#12/0 rds_connect_worker Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7270 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7592 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x910 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:page_ext_iter_next_fast_possible include/linux/page_ext.h:79 [inline] RIP: 0010:page_ext_iter_next include/linux/page_ext.h:162 [inline] RIP: 0010:__page_table_check_zero+0x254/0x430 mm/page_table_check.c:139 Code: fd 1f 0f 87 d1 00 00 00 e8 a9 4c 84 ff 4c 89 e7 4c 89 fe e8 6e 4f 84 ff 4d 39 fc 0f 83 df 00 00 00 48 8b 44 24 08 4a 8d 1c 20 <48> 89 de 48 81 e6 ff 7f 00 00 31 ff e8 3b 52 84 ff 48 89 d8 48 25 RSP: 0018:ffffc9000660f518 EFLAGS: 00000297 RAX: 000000000002c2d0 RBX: 000000000002c2d1 RCX: ffff88802cca1f40 RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000001 RBP: 0000000000000003 R08: ffff88801c94e14f R09: 1ffff11003929c29 R10: dffffc0000000000 R11: ffffed1003929c2a R12: 0000000000000001 R13: ffff88801c94e100 R14: 0000000000000003 R15: 0000000000000008 page_table_check_free include/linux/page_table_check.h:46 [inline] __free_pages_prepare mm/page_alloc.c:1419 [inline] __free_frozen_pages+0xca3/0xd90 mm/page_alloc.c:2962 __slab_free+0x274/0x2c0 mm/slub.c:5815 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:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] kmem_cache_alloc_noprof+0x2b9/0x600 mm/slub.c:5010 sk_prot_alloc+0x57/0x210 net/core/sock.c:2245 sk_alloc+0x3a/0x390 net/core/sock.c:2307 inet_create+0x7a9/0xff0 net/ipv4/af_inet.c:333 __sock_create+0x4b3/0x9d0 net/socket.c:1676 rds_tcp_conn_path_connect+0x2d8/0x920 net/rds/tcp_connect.c:-1 rds_connect_worker+0x1d8/0x290 net/rds/threads.c:176 process_one_work kernel/workqueue.c:3396 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560 kthread+0x38b/0x480 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 task:syz-executor state:R running task stack:22256 pid:22750 tgid:22750 ppid:22736 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7270 preempt_schedule_common+0x7f/0xd0 kernel/sched/core.c:7449 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:201 [inline] _raw_spin_unlock+0x41/0x50 kernel/locking/spinlock.c:213 spin_unlock include/linux/spinlock.h:401 [inline] copy_pte_range mm/memory.c:1429 [inline] copy_pmd_range+0x5176/0x5c10 mm/memory.c:1490 copy_pud_range mm/memory.c:1527 [inline] copy_p4d_range mm/memory.c:1551 [inline] copy_page_range+0xc82/0x1290 mm/memory.c:1637 dup_mmap+0xf17/0x1dc0 mm/mmap.c:1819 dup_mm kernel/fork.c:1543 [inline] copy_mm+0x11a/0x480 kernel/fork.c:1595 copy_process+0x1e75/0x43e0 kernel/fork.c:2307 kernel_clone+0x2d7/0x940 kernel/fork.c:2766 __do_sys_clone kernel/fork.c:2908 [inline] __se_sys_clone kernel/fork.c:2892 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2892 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa29bfc6bd2 RSP: 002b:00007fa29c34fc60 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fa29c34fc60 RCX: 00007fa29bfc6bd2 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007fa29c34fdec R08: 0000000000000000 R09: 0000000000000001 R10: 0000555594cc97d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 000000000024f1cd R15: 00007fa29c34fe40 rcu: rcu_preempt kthread starved for 4212 jiffies! g409745 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27496 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7270 __schedule_loop kernel/sched/core.c:7347 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7362 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330 kthread+0x38b/0x480 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 11186 Comm: kworker/u8:29 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: krds_cp_wq#14/0 rds_connect_worker RIP: 0010:arch_irqs_disabled_flags arch/x86/include/asm/irqflags.h:146 [inline] RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:153 [inline] RIP: 0010:lock_release+0x277/0x3c0 kernel/locking/lockdep.c:5933 Code: e8 6e 31 00 00 48 8b 5c 24 08 48 c7 c7 30 d4 6f 8e e8 7d 24 41 0a b8 ff ff ff ff 65 0f c1 05 68 76 f1 11 83 f8 01 75 2e 9c 58 00 02 00 00 75 42 f7 c3 00 02 00 00 75 47 65 48 8b 05 ba 31 f1 RSP: 0018:ffffc90000a17d98 EFLAGS: 00000046 RAX: 0000000000000046 RBX: 0000000000000206 RCX: 8000000000000101 RDX: ffffc90000a17e01 RSI: ffffffff8e6fd430 RDI: ffffffff8c6d9480 RBP: ffff888032fe4b20 R08: ffffc90000a18f48 R09: 0000000000000000 R10: ffffc90000a17ef8 R11: fffff52000142fe1 R12: 0000000000000006 R13: 0000000000000006 R14: ffffffff8ed5c6e0 R15: ffff888032fe3e80 FS: 0000000000000000(0000) GS:ffff888124dd8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000140 CR3: 0000000078ac2000 CR4: 00000000003526f0 Call Trace: rcu_lock_release include/linux/rcupdate.h:319 [inline] rcu_read_unlock include/linux/rcupdate.h:880 [inline] class_rcu_destructor include/linux/rcupdate.h:1216 [inline] unwind_next_frame+0x1baa/0x2550 arch/x86/kernel/unwind_orc.c:709 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:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] kmem_cache_alloc_node_noprof+0x354/0x610 mm/slub.c:5068 __alloc_skb+0x1db/0x7a0 net/core/skbuff.c:704 alloc_skb include/linux/skbuff.h:1384 [inline] synproxy_send_client_synack+0x175/0xde0 net/netfilter/nf_synproxy_core.c:463 nft_synproxy_eval_v4+0x362/0x4e0 net/netfilter/nft_synproxy.c:59 nft_synproxy_do_eval+0x335/0x550 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x48d/0x1b10 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:165 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:280 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:323 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:325 __netif_receive_skb_one_core net/core/dev.c:6264 [inline] __netif_receive_skb net/core/dev.c:6377 [inline] process_backlog+0xa6b/0x18b0 net/core/dev.c:6728 __napi_poll+0xaa/0x330 net/core/dev.c:7787 napi_poll net/core/dev.c:7850 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:8007 handle_softirqs+0x226/0x860 kernel/softirq.c:645 do_softirq+0x77/0xd0 kernel/softirq.c:546 __local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473 lock_sock include/net/sock.h:1713 [inline] rds_tcp_tune+0x220/0x920 net/rds/tcp.c:583 rds_tcp_conn_path_connect+0x2fa/0x920 net/rds/tcp_connect.c:137 rds_connect_worker+0x1d8/0x290 net/rds/threads.c:176 process_one_work kernel/workqueue.c:3396 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560 kthread+0x38b/0x480 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: 8 callbacks suppressed IPVS: wrr: UDP 224.0.0.2:0 - no destination available IPVS: wrr: UDP 224.0.0.2:0 - no destination available IPVS: wrr: UDP 224.0.0.2:0 - no destination available IPVS: wrr: UDP 224.0.0.2:0 - no destination available IPVS: wrr: UDP 224.0.0.2:0 - no destination available IPVS: wrr: UDP 224.0.0.2:0 - no destination available