rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12030/1:b..l P2/1:b..l rcu: (detected by 1, t=10502 jiffies, g=64109, q=885 ncpus=2) task:kthreadd state:R running task stack:24656 pid:2 tgid:2 ppid:0 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x190e/0x4c90 kernel/sched/core.c:6765 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7087 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:122 [inline] RIP: 0010:lock_release+0x12a/0xa30 kernel/locking/lockdep.c:5864 Code: 7e 85 c0 0f 85 46 05 00 00 65 48 8b 04 25 80 d6 03 00 48 89 44 24 20 48 8d 98 ec 0a 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 38 <84> c0 0f 85 fb 05 00 00 83 3b 00 0f 85 14 05 00 00 4c 89 f0 48 c1 RSP: 0018:ffffc90000077480 EFLAGS: 00000a07 RAX: 0000000000000000 RBX: ffff8881404aa8ec RCX: ffffffff819cfb90 RDX: 0000000000000000 RSI: ffffffff8c810080 RDI: ffffffff8c810040 RBP: ffffc900000775a8 R08: ffffffff903cfb77 R09: 1ffffffff2079f6e R10: dffffc0000000000 R11: fffffbfff2079f6f R12: 1ffff9200000ee9c R13: ffffffff8234f1d7 R14: ffffffff8eb393e0 R15: dffffc0000000000 rcu_lock_release include/linux/rcupdate.h:347 [inline] rcu_read_unlock include/linux/rcupdate.h:880 [inline] page_ext_put+0xa3/0xc0 mm/page_ext.c:550 page_table_check_free include/linux/page_table_check.h:41 [inline] free_pages_prepare mm/page_alloc.c:1128 [inline] free_frozen_pages+0xe21/0x10e0 mm/page_alloc.c:2660 discard_slab mm/slub.c:2684 [inline] __put_partials+0x160/0x1c0 mm/slub.c:3153 put_cpu_partial+0x17c/0x250 mm/slub.c:3228 __slab_free+0x290/0x380 mm/slub.c:4479 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4115 [inline] slab_alloc_node mm/slub.c:4164 [inline] __do_kmalloc_node mm/slub.c:4293 [inline] __kmalloc_noprof+0x236/0x4c0 mm/slub.c:4306 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] lsm_blob_alloc security/security.c:684 [inline] lsm_cred_alloc security/security.c:701 [inline] security_prepare_creds+0x53/0x360 security/security.c:3241 prepare_creds+0x467/0x640 kernel/cred.c:242 copy_creds+0x109/0x9c0 kernel/cred.c:312 copy_process+0x9df/0x3cf0 kernel/fork.c:2267 kernel_clone+0x226/0x8e0 kernel/fork.c:2815 kernel_thread+0x1c0/0x250 kernel/fork.c:2877 create_kthread kernel/kthread.c:487 [inline] kthreadd+0x60d/0x810 kernel/kthread.c:847 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 task:syz.2.1033 state:R running task stack:25776 pid:12030 tgid:12010 ppid:11506 task_flags:0x40044c flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x190e/0x4c90 kernel/sched/core.c:6765 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6944 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6968 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1771 [inline] zap_pmd_range mm/memory.c:1833 [inline] zap_pud_range mm/memory.c:1862 [inline] zap_p4d_range mm/memory.c:1883 [inline] unmap_page_range+0x3a0d/0x4510 mm/memory.c:1904 unmap_vmas+0x3cc/0x5f0 mm/memory.c:1994 exit_mmap+0x283/0xd40 mm/mmap.c:1284 __mmput+0x115/0x420 kernel/fork.c:1356 exit_mm+0x220/0x310 kernel/exit.c:570 do_exit+0x9ad/0x2940 kernel/exit.c:925 do_group_exit+0x207/0x2c0 kernel/exit.c:1087 get_signal+0x168c/0x1720 kernel/signal.c:3036 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff871d8d169 RSP: 002b:00007ff872b8b0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007ff871fa6088 RCX: 00007ff871d8d169 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff871fa6088 RBP: 00007ff871fa6080 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff871fa608c R13: 0000000000000000 R14: 00007ff8720cf940 R15: 00007ff8720cfa28 rcu: rcu_preempt kthread starved for 7873 jiffies! g64109 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:25784 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x190e/0x4c90 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6857 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2024 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 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: 0 Comm: swapper/0 Not tainted 6.14.0-rc7-syzkaller-00137-g5fc319360819 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:ip6_packet_match net/ipv6/netfilter/ip6_tables.c:60 [inline] RIP: 0010:ip6t_do_table+0x6b2/0x18a0 net/ipv6/netfilter/ip6_tables.c:306 Code: 00 fc ff df 80 3c 08 00 74 08 4c 89 f7 e8 d6 fa 6d f7 49 23 1e 4c 09 eb 41 0f 95 c6 31 ff 48 89 de e8 12 c0 06 f7 8b 44 24 30 <24> 10 0f b6 d8 31 ff 89 de e8 20 be 06 f7 84 db 0f 94 c0 44 30 f0 RSP: 0018:ffffc90000007300 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8e896580 RDX: ffffffff8e896580 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900000074f0 R08: ffffffff8abb254e R09: 0000000000000000 R10: ffffc90000007450 R11: fffff52000000e8e R12: ffff888059476110 R13: 0000000000000000 R14: ffff888059476100 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcc3bcceccc CR3: 00000000250f4000 CR4: 00000000003526f0 DR0: fffffffffffffffc DR1: 0000000000000006 DR2: 0200000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ip6table_mangle_hook+0x293/0x760 net/ipv6/netfilter/ip6table_mangle.c:73 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 ip6_input+0x169/0x270 net/ipv6/ip6_input.c:491 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5896 [inline] __netif_receive_skb+0x1ea/0x650 net/core/dev.c:6009 process_backlog+0x662/0x15b0 net/core/dev.c:6357 __napi_poll+0xcb/0x490 net/core/dev.c:7191 napi_poll net/core/dev.c:7260 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:7382 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561 __do_softirq kernel/softirq.c:595 [inline] invoke_softirq kernel/softirq.c:435 [inline] __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline] RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:92 [inline] RIP: 0010:acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:112 Code: 90 90 90 90 90 90 90 90 90 65 48 8b 04 25 80 d6 03 00 48 f7 00 08 00 00 00 75 10 66 90 0f 00 2d 65 61 81 00 f3 0f 1e fa fb f4 c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 RSP: 0018:ffffffff8e807ca8 EFLAGS: 00000246 RAX: ffffffff8e896580 RBX: ffff8881436df864 RCX: 00000000000d5bf9 RDX: 0000000000000001 RSI: ffff8881436df800 RDI: ffff8881436df864 RBP: 000000000003aab8 R08: ffff8880b863799b R09: 1ffff110170c6f33 R10: dffffc0000000000 R11: ffffffff8c093010 R12: ffff888144af3800 R13: 0000000000000001 R14: 0000000000000001 R15: ffffffff8f3384a0 acpi_idle_enter+0xe4/0x140 drivers/acpi/processor_idle.c:699 cpuidle_enter_state+0x109/0x470 drivers/cpuidle/cpuidle.c:268 cpuidle_enter+0x5d/0xa0 drivers/cpuidle/cpuidle.c:389 call_cpuidle kernel/sched/idle.c:155 [inline] cpuidle_idle_call kernel/sched/idle.c:230 [inline] do_idle+0x372/0x5c0 kernel/sched/idle.c:325 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423 rest_init+0x2dc/0x300 init/main.c:743 start_kernel+0x484/0x510 init/main.c:1099 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:515 x86_64_start_kernel+0x66/0x70 arch/x86/kernel/head64.c:496 common_startup_64+0x13e/0x147