rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=ee14/1/0x4000000000000000 softirq=17867/17869 fqs=3 rcu: (detected by 0, t=10502 jiffies, g=12657, q=505 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6557 Comm: syz.0.189 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:check_preemption_disabled+0x45/0x120 lib/smp_processor_id.c:53 Code: 4d 13 07 65 8b 0d 0b 4d 13 07 f7 c1 ff ff ff 7f 74 23 65 48 8b 0d eb 4c 13 07 48 3b 4c 24 08 0f 85 cc 00 00 00 48 83 c4 10 5b <41> 5e 41 5f 5d e9 51 ca 02 00 cc 48 c7 04 24 00 00 00 00 9c 8f 04 RSP: 0000:ffffc9000bc5f738 EFLAGS: 00000086 RAX: 0000000000000001 RBX: 0000000000000083 RCX: 9363545158eab300 RDX: 0000000000000000 RSI: ffffffff8d71ebcb RDI: ffffffff8b9ec2e0 RBP: ffff88805987c7b0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200178bee8 R12: 0000000000000000 R13: 0000000000000000 R14: ffff8880b8927ad8 R15: ffff88805987bc80 FS: 00007f3211cb16c0(0000) GS:ffff888126473000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b31723ffc CR3: 0000000032dd2000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline] lock_release+0x27a/0x3e0 kernel/locking/lockdep.c:5891 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline] _raw_spin_unlock_irqrestore+0x70/0x110 kernel/locking/spinlock.c:194 unlock_hrtimer_base kernel/time/hrtimer.c:1013 [inline] hrtimer_try_to_cancel+0x3be/0x420 kernel/time/hrtimer.c:1360 hrtimer_cancel+0x3b/0x50 kernel/time/hrtimer.c:1481 perf_swevent_cancel_hrtimer kernel/events/core.c:11830 [inline] cpu_clock_event_stop+0xd9/0x130 kernel/events/core.c:11880 __perf_event_overflow+0x57d/0xe40 kernel/events/core.c:10346 perf_swevent_hrtimer+0x3b8/0x500 kernel/events/core.c:11786 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x4dd/0xc60 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0x52/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0033:0x7f3210d8eec9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3211cb10e8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007f3210fe5fa8 RCX: 00007f3210d8eec9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3210fe5fa8 RBP: 00007f3210fe5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3210fe6038 R14: 00007ffc97ca94c0 R15: 00007ffc97ca95a8 rcu: rcu_preempt kthread starved for 10496 jiffies! g12657 f0x0 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:27432 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 6558 Comm: syz.0.189 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:__sanitizer_cov_trace_pc+0x3c/0x70 kernel/kcov.c:220 Code: 8b 15 38 5a 8c 10 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 7c 16 00 00 00 74 2c 8b 91 58 16 00 00 83 fa 02 75 21 <48> 8b 91 60 16 00 00 48 8b 32 48 8d 7e 01 8b 89 5c 16 00 00 48 39 RSP: 0018:ffffc90003cd6a38 EFLAGS: 00000246 RAX: ffffffff81b306ab RBX: 1ffff11017127f61 RCX: ffff88802c1b9e40 RDX: 0000000000000002 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90003cd6bc0 R08: ffffffff8f5cd537 R09: 1ffffffff1eb9aa6 R10: dffffc0000000000 R11: fffffbfff1eb9aa7 R12: ffff8880b893fb08 R13: dffffc0000000000 R14: ffff8880b883b1c0 R15: 0000000000000001 FS: 00007f3211c906c0(0000) GS:ffff888126373000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000002100 CR3: 0000000032dd2000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0xd4b/0x12d0 kernel/smp.c:877 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2653 [inline] smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2863 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_slow_inc_cpuslocked+0x86/0x120 kernel/jump_label.c:168 static_key_slow_inc+0x1a/0x30 kernel/jump_label.c:191 nf_static_key_inc net/netfilter/core.c:374 [inline] __nf_register_net_hook+0x727/0x930 net/netfilter/core.c:451 nf_register_net_hook+0xb2/0x190 net/netfilter/core.c:575 nf_register_net_hooks+0x44/0x1b0 net/netfilter/core.c:591 nf_defrag_ipv6_enable+0x87/0x120 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:157 nf_ct_netns_do_get+0x1e7/0x5a0 net/netfilter/nf_conntrack_proto.c:466 nft_connlimit_do_init+0x1de/0x2e0 net/netfilter/nft_connlimit.c:88 nf_tables_newexpr net/netfilter/nf_tables_api.c:3535 [inline] nft_expr_init net/netfilter/nf_tables_api.c:3577 [inline] nft_set_elem_expr_alloc+0x1db/0x590 net/netfilter/nf_tables_api.c:6708 nft_set_expr_alloc+0x68/0x760 net/netfilter/nf_tables_api.c:5251 nf_tables_newset+0x1c47/0x2530 net/netfilter/nf_tables_api.c:5606 nfnetlink_rcv_batch net/netfilter/nfnetlink.c:524 [inline] nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:647 [inline] nfnetlink_rcv+0x112f/0x2520 net/netfilter/nfnetlink.c:665 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg+0x219/0x270 net/socket.c:729 ____sys_sendmsg+0x505/0x830 net/socket.c:2617 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2671 __sys_sendmsg net/socket.c:2703 [inline] __do_sys_sendmsg net/socket.c:2708 [inline] __se_sys_sendmsg net/socket.c:2706 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2706 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3210d8eec9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3211c90038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f3210fe6090 RCX: 00007f3210d8eec9 RDX: 0000000000000040 RSI: 0000200000009b40 RDI: 0000000000000006 RBP: 00007f3210e11f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3210fe6128 R14: 00007f3210fe6090 R15: 00007ffc97ca95a8