rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=25977, q=624 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4295013038-4295002535), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10504 jiffies! g25977 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:25848 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x17fb/0x4be0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6848 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/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: 16 Comm: ksoftirqd/0 Not tainted 6.13.0-rc2-syzkaller-00036-g231825b2e1ff #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024 RIP: 0010:check_preemption_disabled+0x4b/0x120 lib/smp_processor_id.c:55 Code: 8b 05 11 7d 43 74 a9 ff ff ff 7f 74 26 65 48 8b 04 25 28 00 00 00 48 3b 44 24 08 0f 85 ce 00 00 00 89 d8 48 83 c4 10 5b 41 5c <41> 5e 41 5f c3 cc cc cc cc 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 RSP: 0018:ffffc90000007fc0 EFLAGS: 00000082 RAX: 0000000000000000 RBX: ffffc900001568e8 RCX: ffffffff9a374903 RDX: 0000000000000000 RSI: ffffffff8c099220 RDI: ffffffff8c5ec400 RBP: 0000000000000000 R08: ffffffff90183af7 R09: 1ffffffff203075e R10: dffffc0000000000 R11: ffffc90000007ff8 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efd6ce77ff8 CR3: 000000000e736000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: irq_enter_rcu+0x29/0xe0 kernel/softirq.c:603 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0x99/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x81/0x90 kernel/kcov.c:316 Code: 8d 42 28 4c 39 c8 77 22 89 f8 89 f6 49 ff c2 4c 89 11 48 c7 44 0a 08 05 00 00 00 48 89 44 0a 10 48 89 74 0a 18 4c 89 44 0a 20 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 RSP: 0018:ffffc90000156990 EFLAGS: 00000246 RAX: 0000000000000100 RBX: 0000000000000000 RCX: dffffc0000000000 RDX: ffff88801d2d5a00 RSI: 0000000000000000 RDI: 0000000000000000 RBP: dffffc0000000000 R08: ffffffff8a198f40 R09: 1ffffffff203075e R10: dffffc0000000000 R11: fffffbfff203075f R12: 0000000000000001 R13: ffff888031993000 R14: ffffc90000156a80 R15: ffff888024a17800 __mkroute_output net/ipv4/route.c:2543 [inline] ip_route_output_key_hash_rcu+0xbc0/0x2390 net/ipv4/route.c:2839 ip_route_output_key_hash+0x193/0x2b0 net/ipv4/route.c:2668 __ip_route_output_key include/net/route.h:141 [inline] ip_route_output_flow+0x29/0x140 net/ipv4/route.c:2896 ip_route_output_key include/net/route.h:151 [inline] ip_route_me_harder+0x877/0x1360 net/ipv4/netfilter.c:53 synproxy_send_tcp+0x356/0x6c0 net/netfilter/nf_synproxy_core.c:431 synproxy_send_client_synack+0x8a4/0xe20 net/netfilter/nf_synproxy_core.c:484 nft_synproxy_eval_v4+0x3ca/0x610 net/netfilter/nft_synproxy.c:59 nft_synproxy_do_eval+0x362/0xa60 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x4ad/0x1da0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x418/0x6b0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK+0x29e/0x450 include/linux/netfilter.h:312 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5672 [inline] __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5785 process_backlog+0x662/0x15b0 net/core/dev.c:6117 __napi_poll+0xcb/0x490 net/core/dev.c:6883 napi_poll net/core/dev.c:6952 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:7074 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561 run_ksoftirqd+0xca/0x130 kernel/softirq.c:950 smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244