rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P14418/1:b..l P11978/1:b..l rcu: (detected by 0, t=10503 jiffies, g=69761, q=7168 ncpus=2) task:syz-executor state:R running task stack:21432 pid:11978 tgid:11978 ppid:11972 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 44 41 01 11 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9001b2ef618 EFLAGS: 00000206 RAX: bf40822f65f6a900 RBX: 0000000000000000 RCX: bf40822f65f6a900 RDX: 0000000011b76422 RSI: ffffffff8db7ed49 RDI: ffffffff8be07960 RBP: ffffffff81742f85 R08: ffffffff81742f85 R09: ffffffff8e13f2e0 R10: ffffc9001b2ef7d8 R11: ffffffff81ad9d50 R12: 0000000000000002 R13: ffffffff8e13f2e0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943 discard_slab mm/slub.c:3346 [inline] __put_partials+0x146/0x170 mm/slub.c:3886 put_cpu_partial+0x1f2/0x2d0 mm/slub.c:3961 __slab_free+0x288/0x2a0 mm/slub.c:5956 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x22/0xb0 mm/kasan/common.c:406 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5661 [inline] __kmalloc_noprof+0x41d/0x800 mm/slub.c:5673 kmalloc_noprof include/linux/slab.h:961 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] lsm_blob_alloc security/security.c:192 [inline] lsm_sock_alloc security/security.c:4375 [inline] security_sk_alloc+0x52/0x390 security/security.c:4391 sk_prot_alloc+0x101/0x220 net/core/sock.c:2248 sk_alloc+0x3a/0x390 net/core/sock.c:2301 inet_create+0x7a0/0x1000 net/ipv4/af_inet.c:328 __sock_create+0x4e4/0x960 net/socket.c:1620 sock_create net/socket.c:1678 [inline] __sys_socket_create net/socket.c:1715 [inline] __sys_socket+0xda/0x310 net/socket.c:1762 __do_sys_socket net/socket.c:1776 [inline] __se_sys_socket net/socket.c:1774 [inline] __x64_sys_socket+0x7a/0x90 net/socket.c:1774 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7d2df91667 RSP: 002b:00007ffef71cc4a8 EFLAGS: 00000202 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f7d2df91667 RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000002 RBP: 00007ffef71ccb9c R08: 00007ffef71cc49c R09: 00007ffef71cc8a7 R10: 00007ffef71cc520 R11: 0000000000000202 R12: 0000000000000072 R13: 00000000000927c0 R14: 00000000000a667f R15: 00007ffef71ccbf0 task:syz.1.1848 state:R running task stack:21208 pid:14418 tgid:14418 ppid:11978 task_flags:0x40064c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline] RIP: 0010:lock_release+0x46/0x3b0 kernel/locking/lockdep.c:5879 Code: b0 11 01 11 48 89 44 24 28 0f 1f 44 00 00 65 8b 05 b3 11 01 11 83 f8 08 0f 83 87 02 00 00 89 c0 48 0f a3 05 dc 90 03 0e 73 0d f5 f8 08 00 84 c0 0f 84 a3 02 00 00 83 3d f6 c0 03 0e 00 0f 84 RSP: 0018:ffffc90004c6ed10 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffffffff9044f601 RCX: f8674652588de200 RDX: ffffc90004c6ee01 RSI: ffffffff81742f85 RDI: ffffffff8e13f2e0 RBP: dffffc0000000000 R08: ffffc90004c6f9a0 R09: 0000000000000000 R10: ffffc90004c6ee98 R11: fffff5200098ddd5 R12: ffffc90004c6f9b0 R13: ffffffff81742f85 R14: ffffffff8e13f2e0 R15: ffffffff81742f85 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+0x1ab1/0x23d0 arch/x86/kernel/unwind_orc.c:695 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1406 [inline] free_unref_folios+0xdb3/0x14f0 mm/page_alloc.c:3000 folios_put_refs+0x584/0x670 mm/swap.c:1002 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x49e/0x1490 mm/shmem.c:1137 shmem_truncate_range mm/shmem.c:1249 [inline] shmem_evict_inode+0x26e/0xa70 mm/shmem.c:1379 evict+0x5f4/0xae0 fs/inode.c:837 __dentry_kill+0x209/0x660 fs/dcache.c:670 finish_dput+0xc9/0x480 fs/dcache.c:879 __fput+0x68e/0xa70 fs/file_table.c:476 task_work_run+0x1d4/0x260 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x8bd/0x25b0 kernel/exit.c:971 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112 get_signal+0x1285/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop kernel/entry/common.c:75 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline] irqentry_exit+0x177/0x660 kernel/entry/common.c:196 exc_page_fault+0xab/0x100 arch/x86/mm/fault.c:1535 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f7d2df8f751 RSP: 002b:fffffffffffffe70 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f7d2e1e6180 RCX: 00007f7d2df8f749 RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000 RBP: 00007f7d2e013f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f7d2e1e6218 R14: 00007f7d2e1e6180 R15: 00007ffef71cc7d8 rcu: rcu_preempt kthread starved for 455 jiffies! g69761 f0x0 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:27184 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 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+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 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: 6269 Comm: kworker/u8:18 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:check_preemption_disabled+0x40/0x120 lib/smp_processor_id.c:53 Code: 08 65 8b 05 c6 e1 41 07 65 8b 0d bb e1 41 07 f7 c1 ff ff ff 7f 74 23 65 48 8b 0d 9b e1 41 07 48 3b 4c 24 08 0f 85 cc 00 00 00 <48> 83 c4 10 5b 41 5e 41 5f 5d e9 81 cd 02 00 cc 48 c7 04 24 00 00 RSP: 0018:ffffc90000a07bc0 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 76fdb9ae16196200 RDX: 00000000a42637f2 RSI: ffffffff8db7ed49 RDI: ffffffff8be07960 RBP: ffffffff81742f85 R08: ffffffff81742f85 R09: ffffffff8e13f2e0 R10: ffffc90000a07db8 R11: ffffffff81ad9d50 R12: 0000000000000002 R13: ffffffff8e13f2e0 R14: 0000000000000000 R15: 0000000000000246 FS: 0000000000000000(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff8af31d040 CR3: 000000000df38000 CR4: 00000000003526f0 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline] lock_acquire+0x127/0x340 kernel/locking/lockdep.c:5870 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495 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:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6674 [inline] kmem_cache_free+0x197/0x620 mm/slub.c:6785 skb_release_data+0x62d/0x7c0 net/core/skbuff.c:1107 skb_release_all net/core/skbuff.c:1182 [inline] __kfree_skb net/core/skbuff.c:1196 [inline] consume_skb+0x9e/0xf0 net/core/skbuff.c:1428 nft_synproxy_eval_v4+0x376/0x560 net/netfilter/nft_synproxy.c:60 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+0x40c/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:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:316 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6138 [inline] __netif_receive_skb+0x143/0x380 net/core/dev.c:6251 process_backlog+0x622/0x1500 net/core/dev.c:6603 __napi_poll+0xae/0x320 net/core/dev.c:7667 napi_poll net/core/dev.c:7730 [inline] net_rx_action+0x672/0xe50 net/core/dev.c:7882 handle_softirqs+0x27d/0x850 kernel/softirq.c:626 __do_softirq kernel/softirq.c:660 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:727 irq_exit_rcu+0x9/0x30 kernel/softirq.c:743 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xccf/0x12b0 kernel/smp.c:877 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 aa a6 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 55 a2 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 39 a2 RSP: 0018:ffffc9000be4f660 EFLAGS: 00000293 RAX: ffffffff81b61627 RBX: 1ffff110170c85d1 RCX: ffff888025bdbd00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000be4f7e0 R08: ffffffff8fa22f77 R09: 1ffffffff1f445ee R10: dffffc0000000000 R11: fffffbfff1f445ef R12: ffff8880b8642e88 R13: dffffc0000000000 R14: ffff8880b873bd40 R15: 0000000000000000 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:2711 [inline] smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2921 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x240 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:874 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246