rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P14081/1:b..l rcu: (detected by 1, t=10503 jiffies, g=370705, q=686968 ncpus=2) task:syz-executor state:R running task stack:24232 pid:14081 tgid:14081 ppid:14080 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7228 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7552 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa00 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:__rcu_read_lock+0x4f/0x70 kernel/rcu/tree_plugin.h:416 Code: 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 2c 8b 83 c4 04 00 00 83 c0 01 89 83 c4 04 00 00 8b 83 c4 04 00 00 <3d> ff ff ff 3f 7f 06 5b c3 cc cc cc cc 90 0f 0b 90 5b e9 1a 89 a2 RSP: 0018:ffffc90003ea72b0 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffff88804120ca80 RCX: ffffffff91aef901 RDX: 0000000000000000 RSI: ffffffff84bc481b RDI: ffff88804120cf44 RBP: ffffc90003ea7378 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc90003ea7330 R11: 000000000003bb6f R12: ffffffff81f365e0 R13: ffffc90003ea7330 R14: 0000000000000000 R15: ffff88804120ca80 rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0xae/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x162/0x1e0 mm/page_owner.c:165 __reset_page_owner+0x84/0x190 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1397 [inline] __free_frozen_pages+0x794/0x10a0 mm/page_alloc.c:2938 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x8a/0xb0 mm/kasan/common.c:406 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5334 [inline] __kmalloc_noprof+0x302/0x840 mm/slub.c:5347 _kmalloc_noprof include/linux/slab.h:973 [inline] tomoyo_realpath_from_path+0xb6/0x690 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x2af/0x3c0 security/tomoyo/file.c:776 tomoyo_file_open+0x6b/0x90 security/tomoyo/tomoyo.c:334 security_file_open+0xb5/0x1e0 security/security.c:2739 do_dentry_open+0x588/0x14d0 fs/open.c:924 vfs_open+0x82/0x3f0 fs/open.c:1079 do_open fs/namei.c:4700 [inline] path_openat+0x2873/0x4280 fs/namei.c:4859 do_file_open+0x20e/0x430 fs/namei.c:4888 do_sys_openat2+0x10f/0x1e0 fs/open.c:1395 do_sys_open fs/open.c:1401 [inline] __do_sys_openat fs/open.c:1417 [inline] __se_sys_openat fs/open.c:1412 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1412 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8d5f19c17c RSP: 002b:00007ffe9af010b0 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000432 RCX: 00007f8d5f19c17c RDX: 0000000000090800 RSI: 00007f8d5f2326b1 RDI: 00000000ffffff9c RBP: 00007ffe9af0115c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000141 R13: 0000000000000000 R14: 00000000002df123 R15: 00007ffe9af011b0 rcu: rcu_preempt kthread starved for 2057 jiffies! g370705 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:26904 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7228 __schedule_loop kernel/sched/core.c:7307 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7322 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] RIP: 0010:rcu_is_watching+0x2c/0xc0 kernel/rcu/tree.c:752 Code: 1e fa 55 53 65 ff 05 83 b5 1e 12 e8 6e 60 9f 09 48 c7 c3 68 4c 0d 94 89 c5 83 f8 07 0f 87 82 00 00 00 48 8d 3c ed 20 59 1d 8e <48> b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 RSP: 0018:ffffc90000a07e50 EFLAGS: 00000297 RAX: 0000000000000001 RBX: ffffffff940d4c68 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff8c1ce980 RDI: ffffffff8e1d5928 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc90000a07f50 R11: 000000000000de25 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88812445f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000560cf1e0cbe0 CR3: 0000000064288000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f7 DR2: 00000000ffffffff DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: trace_lock_acquire include/trace/events/lock.h:23 [inline] lock_acquire+0x301/0x370 kernel/locking/lockdep.c:5831 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:840 [inline] class_rcu_constructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4610 [inline] slab_alloc_node mm/slub.c:4939 [inline] kmem_cache_alloc_noprof+0x241/0x6d0 mm/slub.c:4946 kmem_alloc_batch+0x49/0x170 lib/debugobjects.c:371 fill_pool lib/debugobjects.c:420 [inline] debug_objects_fill_pool lib/debugobjects.c:780 [inline] debug_objects_fill_pool+0x24d/0x5a0 lib/debugobjects.c:758 debug_object_activate+0x103/0x490 lib/debugobjects.c:869 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline] __call_rcu_common.constprop.0+0x35/0x9b0 kernel/rcu/tree.c:3144 call_rcu_hurry include/linux/rcupdate.h:125 [inline] dst_release net/core/dst.c:178 [inline] dst_release+0x259/0x330 net/core/dst.c:166 refdst_drop include/net/dst.h:272 [inline] skb_dst_drop include/net/dst.h:284 [inline] skb_release_head_state+0x293/0x400 net/core/skbuff.c:1165 skb_release_all net/core/skbuff.c:1189 [inline] __kfree_skb net/core/skbuff.c:1205 [inline] consume_skb net/core/skbuff.c:1438 [inline] consume_skb+0x8a/0x110 net/core/skbuff.c:1432 nft_synproxy_eval_v4 net/netfilter/nft_synproxy.c:61 [inline] nft_synproxy_do_eval+0xa72/0xd50 net/netfilter/nft_synproxy.c:142 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x2e5/0x1990 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0xf3/0x400 net/netfilter/nft_chain_filter.c:162 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xbf/0x220 net/netfilter/core.c:619 nf_hook.constprop.0+0x2a6/0x750 include/linux/netfilter.h:273 NF_HOOK include/linux/netfilter.h:316 [inline] ip_local_deliver+0x163/0x1f0 net/ipv4/ip_input.c:262 dst_input include/net/dst.h:480 [inline] ip_rcv_finish net/ipv4/ip_input.c:492 [inline] NF_HOOK include/linux/netfilter.h:318 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] ip_rcv+0x33a/0x3c0 net/ipv4/ip_input.c:612 __netif_receive_skb_one_core+0x197/0x1e0 net/core/dev.c:6202 __netif_receive_skb+0x1f/0x120 net/core/dev.c:6315 process_backlog+0x37a/0x1580 net/core/dev.c:6666 __napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7733 napi_poll net/core/dev.c:7796 [inline] net_rx_action+0xa40/0xf20 net/core/dev.c:7953 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: c6 90 02 e9 c3 48 03 00 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 e6 1e 00 fb f4 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197e00 EFLAGS: 00000246 RAX: 000000001cc4b594 RBX: ffff88801e2ba540 RCX: ffffffff8b8cb2b5 RDX: 0000000000000001 RSI: ffffffff8c1ce980 RDI: ffffffff81de1ea7 RBP: ffffed1003c574a8 R08: 0000000000000000 R09: ffffed10170a678d R10: ffff8880b8533c6b R11: ffffffff81d4f52c R12: 0000000000000000 R13: 0000000000000000 R14: 1ffff92000032fc4 R15: dffffc0000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x3a7/0x5b0 kernel/sched/idle.c:355 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x158