rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P22649/3:b..l rcu: (detected by 1, t=10502 jiffies, g=88457, q=550728 ncpus=2) task:syz.0.4317 state:R running task stack:23688 pid:22649 tgid:22647 ppid:17544 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7228 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7409 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __local_bh_enable_ip+0xe1/0x130 kernel/softirq.c:457 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:914 [inline] __dev_queue_xmit+0x1ed7/0x37f0 net/core/dev.c:4907 dev_queue_xmit include/linux/netdevice.h:3436 [inline] neigh_hh_output include/net/neighbour.h:544 [inline] neigh_output include/net/neighbour.h:558 [inline] ip_finish_output2+0xbda/0x10b0 net/ipv4/ip_output.c:236 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_output+0x29f/0x450 net/ipv4/ip_output.c:437 __ip_queue_xmit+0x10df/0x1b10 net/ipv4/ip_output.c:533 __tcp_transmit_skb+0x2d18/0x47c0 net/ipv4/tcp_output.c:1717 tcp_transmit_skb net/ipv4/tcp_output.c:1734 [inline] tcp_connect+0x220b/0x53e0 net/ipv4/tcp_output.c:4375 tcp_v4_connect+0x1051/0x1950 net/ipv4/tcp_ipv4.c:345 tcp_v6_connect+0xcb1/0x1cf0 net/ipv6/tcp_ipv6.c:239 __inet_stream_connect+0x258/0xe00 net/ipv4/af_inet.c:684 inet_stream_connect+0x66/0xa0 net/ipv4/af_inet.c:755 kernel_connect+0x141/0x1c0 net/socket.c:3726 smc_connect+0x78c/0xdb0 net/smc/af_smc.c:1708 __sys_connect_file net/socket.c:2135 [inline] __sys_connect+0x323/0x460 net/socket.c:2154 __do_sys_connect net/socket.c:2160 [inline] __se_sys_connect net/socket.c:2157 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:2157 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: 0033:0x7f152a59ce59 RSP: 002b:00007f152b3ab028 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 00007f152a816090 RCX: 00007f152a59ce59 RDX: 000000000000001c RSI: 00002000000001c0 RDI: 0000000000000006 RBP: 00007f152a632e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f152a816128 R14: 00007f152a816090 R15: 00007ffc69b2d538 rcu: rcu_preempt kthread starved for 677 jiffies! g88457 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:28120 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7228 __schedule_loop kernel/sched/core.c:7307 [inline] schedule+0x164/0x360 kernel/sched/core.c:7322 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: 9555 Comm: kworker/R-bond3 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: 0x0 (bond3) RIP: 0010:check_preemption_disabled+0x14/0xe0 lib/smp_processor_id.c:16 Code: 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 53 65 8b 05 07 5e 92 07 65 8b 0d fc 5d 92 07 c1 ff ff ff 7f 74 0c 5b 41 5e 41 5f 5d e9 59 e2 02 00 cc 9c 59 RSP: 0018:ffffc90000006cf8 EFLAGS: 00000283 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000080000102 RDX: 0000000000000000 RSI: ffffffff8c291100 RDI: ffffffff8c2910c0 RBP: ffffffff8176a21f R08: 0000000000000000 R09: 0000000000000000 R10: ffffc90000006ed8 R11: ffffffff81b10630 R12: 0000000000000002 R13: ffffffff8e959a20 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88812527c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6d24600000 CR3: 0000000032aee000 CR4: 00000000003526f0 Call Trace: rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:752 trace_lock_acquire include/trace/events/lock.h:23 [inline] lock_acquire+0x5f/0x350 kernel/locking/lockdep.c:5831 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:4610 [inline] slab_alloc_node mm/slub.c:4939 [inline] kmem_cache_alloc_node_noprof+0x380/0x680 mm/slub.c:4991 __alloc_skb+0x1d7/0x7a0 net/core/skbuff.c:704 alloc_skb include/linux/skbuff.h:1386 [inline] synproxy_send_client_synack+0x175/0xde0 net/netfilter/nf_synproxy_core.c:463 nft_synproxy_eval_v4+0x37b/0x530 net/netfilter/nft_synproxy.c:60 nft_synproxy_do_eval+0x335/0x550 net/netfilter/nft_synproxy.c:142 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: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:6206 [inline] __netif_receive_skb net/core/dev.c:6319 [inline] process_backlog+0xa34/0x1860 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:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:188 [inline] RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:206 Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ba 74 f7 f5 48 89 df e8 12 ea f7 f5 e8 8d a6 23 f6 fb bf 01 00 00 00 72 01 e9 f5 65 8b 05 bb c3 8f 07 85 c0 74 07 5b c3 cc cc cc cc RSP: 0018:ffffc90003267ce0 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffff88801aea3000 RCX: 0000000080000002 RDX: 0000000000000000 RSI: ffffffff8c291100 RDI: 0000000000000001 RBP: dffffc0000000000 R08: ffffffff903116f7 R09: 1ffffffff20622de R10: dffffc0000000000 R11: fffffbfff20622df R12: ffff8880800584b0 R13: 1ffff1101000b080 R14: ffff888053f97e60 R15: ffff888080058408 rescuer_thread+0xb78/0x10b0 kernel/workqueue.c:3647 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 ip6_tunnel: syztnl0 xmit: Local address not yet configured! net_ratelimit: 5 callbacks suppressed GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog