rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7291/1:b..l rcu: (detected by 1, t=10502 jiffies, g=158677, q=850 ncpus=2) task:syz.8.5877 state:R running task stack:25192 pid:7291 tgid:7290 ppid:27666 task_flags:0x400140 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256 irqentry_exit+0x36/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:124 [inline] RIP: 0010:lock_release+0x77/0x2f0 kernel/locking/lockdep.c:5881 Code: 53 8b e9 0e 85 ff 0f 84 25 01 00 00 65 8b 05 b8 2e 09 12 85 c0 0f 85 16 01 00 00 65 4c 8b 35 f8 ec 08 12 41 8b b6 2c 0b 00 00 <85> f6 0f 85 ff 00 00 00 48 81 3b 40 75 a8 93 0f 84 f2 00 00 00 9c RSP: 0018:ffffc900051d7438 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff8e3c4760 RCX: ffffc900051d8001 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000082773 R12: ffffffff816bf704 R13: ffffc900051d74f0 R14: ffff888036dfc900 R15: ffffc900051d7524 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x3f9/0x20a0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:311 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0x7df/0x1160 mm/page_alloc.c:2901 vfree+0x1fd/0xb50 mm/vmalloc.c:3440 htable_put net/netfilter/xt_hashlimit.c:426 [inline] hashlimit_mt_destroy_v1+0x78/0x90 net/netfilter/xt_hashlimit.c:972 cleanup_match net/ipv6/netfilter/ip6_tables.c:477 [inline] find_check_entry.constprop.0+0x511/0xa20 net/ipv6/netfilter/ip6_tables.c:581 translate_table+0xd0b/0x17b0 net/ipv6/netfilter/ip6_tables.c:733 do_replace net/ipv6/netfilter/ip6_tables.c:1154 [inline] do_ip6t_set_ctl+0x570/0xb00 net/ipv6/netfilter/ip6_tables.c:1644 nf_setsockopt+0x8d/0xf0 net/netfilter/nf_sockopt.c:101 ipv6_setsockopt+0x135/0x170 net/ipv6/ipv6_sockglue.c:978 rawv6_setsockopt+0xc2/0x510 net/ipv6/raw.c:1046 do_sock_setsockopt+0xf3/0x1d0 net/socket.c:2360 __sys_setsockopt+0x1a0/0x230 net/socket.c:2385 __do_sys_setsockopt net/socket.c:2391 [inline] __se_sys_setsockopt net/socket.c:2388 [inline] __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2388 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f18a738f749 RSP: 002b:00007f18a81ca038 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007f18a75e5fa0 RCX: 00007f18a738f749 RDX: 0000000000000040 RSI: 0000000000000029 RDI: 0000000000000003 RBP: 00007f18a7413f91 R08: 00000000000003f8 R09: 0000000000000000 R10: 0000200000000840 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f18a75e6038 R14: 00007f18a75e5fa0 R15: 00007ffcc6ec7a98 rcu: rcu_preempt kthread starved for 10228 jiffies! g158677 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:28024 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7026 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x675/0x7d0 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: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 97 6c 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 83 35 29 00 fb f4 3c 0a 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c6 RAX: 0000000005ada2f5 RBX: 0000000000000000 RCX: ffffffff8b60f2a9 RDX: 0000000000000000 RSI: ffffffff8da2c99d RDI: ffffffff8bf07440 RBP: fffffbfff1c12f40 R08: 0000000000000001 R09: ffffed1017086655 R10: ffff8880b84332ab R11: 0000000000000001 R12: 0000000000000000 R13: ffffffff8e097a00 R14: ffffffff90821dd0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124a05000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f161ee53348 CR3: 00000000759ba000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x38d/0x500 kernel/sched/idle.c:330 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428 rest_init+0x16b/0x2b0 init/main.c:757 start_kernel+0x3f6/0x4e0 init/main.c:1111 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x148