rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5220/1:b..l rcu: (detected by 1, t=10503 jiffies, g=11353, q=1510387 ncpus=2) task:sshd state:R running task stack:24224 pid:5220 tgid:5220 ppid:4975 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0xef5/0x5750 kernel/sched/core.c:6675 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6854 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 unwind_next_frame+0x1776/0x20c0 arch/x86/kernel/unwind_orc.c:672 arch_stack_walk+0x95/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122 save_stack+0x162/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x8d/0x400 mm/page_owner.c:297 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1108 [inline] free_unref_page+0x5f4/0xdc0 mm/page_alloc.c:2638 __put_partials+0x14c/0x170 mm/slub.c:3146 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:247 [inline] slab_post_alloc_hook mm/slub.c:4086 [inline] slab_alloc_node mm/slub.c:4135 [inline] kmem_cache_alloc_node_noprof+0x153/0x310 mm/slub.c:4187 kmalloc_reserve+0x18b/0x2c0 net/core/skbuff.c:587 __alloc_skb+0x164/0x380 net/core/skbuff.c:678 alloc_skb_fclone include/linux/skbuff.h:1372 [inline] tcp_stream_alloc_skb+0x34/0x570 net/ipv4/tcp.c:885 tcp_sendmsg_locked+0xeb5/0x3750 net/ipv4/tcp.c:1167 tcp_sendmsg+0x2e/0x50 net/ipv4/tcp.c:1357 inet_sendmsg+0xb9/0x140 net/ipv4/af_inet.c:853 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg net/socket.c:744 [inline] sock_write_iter+0x4ac/0x5b0 net/socket.c:1165 new_sync_write fs/read_write.c:590 [inline] vfs_write+0x6b5/0x1140 fs/read_write.c:683 ksys_write+0x1fa/0x260 fs/read_write.c:736 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb77ad16bf2 RSP: 002b:00007fffb6c1f318 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000000006c RCX: 00007fb77ad16bf2 RDX: 000000000000006c RSI: 0000556cf23dd9b0 RDI: 0000000000000004 RBP: 0000556cf23c02a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000556cc7b02aa4 R13: 000000000000008d R14: 0000556cc7b033e8 R15: 00007fffb6c1f388 rcu: rcu_preempt kthread starved for 10540 jiffies! g11353 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:27120 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0xef5/0x5750 kernel/sched/core.c:6675 __schedule_loop kernel/sched/core.c:6752 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6767 schedule_timeout+0x136/0x2a0 kernel/time/timer.c:2615 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2045 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2247 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 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: 939 Comm: kworker/0:2 Not tainted 6.12.0-rc1-syzkaller-00113-g8c245fe7dde3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events nsim_dev_trap_report_work RIP: 0010:nf_nat_inet_fn+0x37f/0xc20 net/netfilter/nf_nat_core.c:931 Code: e9 9b 00 00 00 e8 d1 75 43 f8 4c 89 e6 bf 07 00 00 00 e8 34 78 43 f8 49 83 fc 07 76 7e c7 44 24 18 00 00 00 00 e9 3d fd ff ff ac 75 43 f8 4c 89 e6 bf 07 00 00 00 e8 0f 78 43 f8 49 83 fc 07 RSP: 0018:ffffc90000007250 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffc90000007398 RCX: ffffffff894a1033 RDX: ffff888026240000 RSI: 0000000000000004 RDI: 0000000000000001 RBP: 0000000000000004 R08: 0000000000000001 R09: 0000000000000004 R10: 0000000000000004 R11: 0000000000000000 R12: ffff888073638003 R13: ffff888073638003 R14: ffff888012a3e1c0 R15: ffff8881ebd79000 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000080 CR3: 0000000074ac2000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: nf_nat_ipv4_fn net/netfilter/nf_nat_proto.c:645 [inline] nf_nat_ipv4_out+0x96/0x4d0 net/netfilter/nf_nat_proto.c:765 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xbb/0x200 net/netfilter/core.c:626 nf_hook+0x386/0x6d0 include/linux/netfilter.h:269 NF_HOOK_COND include/linux/netfilter.h:302 [inline] ip_output+0x1bc/0x2a0 net/ipv4/ip_output.c:434 dst_output include/net/dst.h:450 [inline] ip_local_out+0x33e/0x4a0 net/ipv4/ip_output.c:130 synproxy_send_tcp.isra.0+0x439/0x630 net/netfilter/nf_synproxy_core.c:439 synproxy_send_client_synack+0x94c/0xcf0 net/netfilter/nf_synproxy_core.c:484 nft_synproxy_eval_v4 net/netfilter/nft_synproxy.c:59 [inline] nft_synproxy_do_eval+0xa49/0xd60 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x2e6/0x18f0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x18b/0x350 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xbb/0x200 net/netfilter/core.c:626 nf_hook.constprop.0+0x42e/0x750 include/linux/netfilter.h:269 NF_HOOK include/linux/netfilter.h:312 [inline] ip_local_deliver+0x169/0x1f0 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:460 [inline] ip_rcv_finish net/ipv4/ip_input.c:449 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] NF_HOOK include/linux/netfilter.h:308 [inline] ip_rcv+0x2c3/0x5d0 net/ipv4/ip_input.c:569 __netif_receive_skb_one_core+0x199/0x1e0 net/core/dev.c:5666 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5779 process_backlog+0x443/0x15f0 net/core/dev.c:6111 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:6775 napi_poll net/core/dev.c:6844 [inline] net_rx_action+0xa92/0x1010 net/core/dev.c:6966 handle_softirqs+0x213/0x8f0 kernel/softirq.c:554 do_softirq kernel/softirq.c:455 [inline] do_softirq+0xb2/0xf0 kernel/softirq.c:442 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:382 spin_unlock_bh include/linux/spinlock.h:396 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:820 [inline] nsim_dev_trap_report_work+0x870/0xc80 drivers/net/netdevsim/dev.c:850 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 3.437 msecs