rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5581/1:b..l rcu: (detected by 0, t=10503 jiffies, g=32501, q=1207069 ncpus=2) task:crond state:R running task stack:24104 pid:5581 tgid:5581 ppid:1 task_flags:0x400000 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6786 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7109 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:55 [inline] RIP: 0010:stack_access_ok arch/x86/kernel/unwind_orc.c:393 [inline] RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline] RIP: 0010:unwind_next_frame+0xabc/0x2390 arch/x86/kernel/unwind_orc.c:585 Code: 76 01 83 e6 07 83 fe 04 4c 89 64 24 10 0f 84 49 04 00 00 83 fe 03 0f 84 f3 01 00 00 83 fe 02 0f 85 a1 07 00 00 4c 89 7c 24 28 <4d> 8d 7e 08 4c 89 fd 48 c1 ed 03 48 b8 00 00 00 00 00 fc ff df 80 RSP: 0018:ffffc90003c4f778 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff903e95b9 RCX: ffffffff8fbe2848 RDX: ffffffff903e95b4 RSI: 0000000000000002 RDI: ffffffff8be1b860 RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffffff8172aae5 R10: ffffc90003c4f898 R11: ffffffff81acff40 R12: ffffc90003c4fdc0 R13: ffffc90003c4f898 R14: ffffc90003c4f848 R15: 1ffffffff207d2b7 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf7/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1248 [inline] __free_frozen_pages+0xc65/0xe60 mm/page_alloc.c:2706 discard_slab mm/slub.c:2717 [inline] __put_partials+0x161/0x1c0 mm/slub.c:3186 put_cpu_partial+0x17c/0x250 mm/slub.c:3261 __slab_free+0x2f7/0x400 mm/slub.c:4513 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4148 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4204 getname_flags+0xb8/0x540 fs/namei.c:146 getname include/linux/fs.h:2907 [inline] do_sys_openat2+0xbc/0x1c0 fs/open.c:1431 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 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: 0033:0x7f3b1298dc3a RSP: 002b:00007ffdc2b17e28 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000564494c192a0 RCX: 00007f3b1298dc3a RDX: 0000000000080000 RSI: 00007f3b12a2a45a RDI: 00000000ffffff9c RBP: 0000000000000008 R08: 0000000000000008 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000206 R12: 00007f3b12a287f4 R13: 00007f3b12a287f4 R14: 0000000000000001 R15: 0000000000000033 rcu: rcu_preempt kthread starved for 1322 jiffies! g32501 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:27128 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6786 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7109 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:118 [inline] RIP: 0010:lock_release+0x63/0x3e0 kernel/locking/lockdep.c:5884 Code: 00 89 c0 48 0f a3 05 7c 61 02 0e 73 16 e8 d5 df 08 00 84 c0 75 0d f6 05 72 4c ec 0d 01 0f 84 ad 02 00 00 83 3d 9d 92 02 0e 00 <0f> 84 44 02 00 00 65 8b 05 a0 64 fe 10 85 c0 0f 85 35 02 00 00 65 RSP: 0018:ffffc900001572b0 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffffff9033c801 RCX: 591a088101ee4400 RDX: ffffc90000157401 RSI: ffffffff8be1b8a0 RDI: ffffffff8be1b860 RBP: dffffc0000000000 R08: ffffc90000157d90 R09: 0000000000000000 R10: ffffc90000157438 R11: fffff5200002ae89 R12: ffffc90000157da0 R13: ffffffff8172aae5 R14: ffffffff8e13f0e0 R15: ffffffff8172aae5 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:319 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4148 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4204 kmem_alloc_batch lib/debugobjects.c:371 [inline] fill_pool+0x100/0x570 lib/debugobjects.c:403 debug_objects_fill_pool lib/debugobjects.c:725 [inline] debug_object_assert_init+0x2b1/0x380 lib/debugobjects.c:1003 debug_timer_assert_init kernel/time/timer.c:803 [inline] debug_assert_init kernel/time/timer.c:848 [inline] __try_to_del_timer_sync+0x29/0x3a0 kernel/time/timer.c:1457 __timer_delete_sync+0x1fe/0x2d0 kernel/time/timer.c:1620 schedule_timeout+0x133/0x270 kernel/time/sleep_timeout.c:100 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6451 Comm: ipvs-e:3:0 Not tainted 6.16.0-rc6-syzkaller-00121-g6832a9317eee #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:check_preemption_disabled+0x49/0x120 lib/smp_processor_id.c:55 Code: 8b 0d eb ed 35 07 f7 c1 ff ff ff 7f 74 23 65 48 8b 0d cb ed 35 07 48 3b 4c 24 08 0f 85 cc 00 00 00 48 83 c4 10 5b 41 5e 41 5f <5d> c3 cc cc cc cc cc 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 RSP: 0018:ffffc90000a07b08 EFLAGS: 00000086 RAX: 0000000000000001 RBX: 0000000000000000 RCX: c6ab5c258603a400 RDX: 0000000000000000 RSI: ffffffff8db6f200 RDI: ffffffff8be1b8c0 RBP: ffffffff8172aae5 R08: 0000000000000000 R09: ffffffff8172aae5 R10: ffffc90000a07cd8 R11: ffffffff81acff40 R12: 0000000000000002 R13: ffffffff8e13f0e0 R14: 0000000000000000 R15: 0000000000000246 FS: 0000000000000000(0000) GS:ffff888125d59000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007febff0903d0 CR3: 0000000030c70000 CR4: 00000000003526f0 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:473 [inline] lock_acquire+0x130/0x360 kernel/locking/lockdep.c:5873 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:319 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4148 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_node_noprof+0x1bb/0x3c0 mm/slub.c:4249 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:660 alloc_skb include/linux/skbuff.h:1336 [inline] synproxy_send_client_synack+0x16c/0xe20 net/netfilter/nf_synproxy_core.c:460 nft_synproxy_eval_v4+0x36e/0x560 net/netfilter/nft_synproxy.c:59 nft_synproxy_do_eval+0x345/0x570 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x409/0x1920 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x25d/0x340 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:157 [inline] nf_hook_slow+0xc2/0x220 net/netfilter/core.c:623 nf_hook include/linux/netfilter.h:272 [inline] NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:315 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:317 __netif_receive_skb_one_core net/core/dev.c:5977 [inline] __netif_receive_skb+0x143/0x380 net/core/dev.c:6090 process_backlog+0x60e/0x14f0 net/core/dev.c:6442 __napi_poll+0xc7/0x480 net/core/dev.c:7414 napi_poll net/core/dev.c:7478 [inline] net_rx_action+0x707/0xe30 net/core/dev.c:7605 handle_softirqs+0x283/0x870 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194 Code: 74 05 e8 eb bd 5e f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 33 ec 27 f6 65 8b 05 fc 79 33 07 85 c0 74 40 48 c7 04 24 0e 36 RSP: 0018:ffffc900034a78c0 EFLAGS: 00000206 RAX: c6ab5c258603a400 RBX: 0000000000000a06 RCX: c6ab5c258603a400 RDX: 0000000000000000 RSI: ffffffff8d9827b9 RDI: 0000000000000001 RBP: ffffc900034a7950 R08: ffffffff8fa0acf7 R09: 1ffffffff1f4159e R10: dffffc0000000000 R11: fffffbfff1f4159f R12: dffffc0000000000 R13: dead000000000122 R14: ffffffff99cb9cd0 R15: 1ffff92000694f18 debug_object_free+0x29a/0x340 lib/debugobjects.c:975 schedule_timeout+0x13b/0x270 kernel/time/sleep_timeout.c:103 ip_vs_estimation_kthread+0x2a31/0x3a00 net/netfilter/ipvs/ip_vs_est.c:209 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245