rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5847/1:b..l P9152/1:b..l P9170/1:b..l rcu: (detected by 0, t=10503 jiffies, g=39025, q=1603681 ncpus=2) task:syz.4.824 state:R running task stack:25312 pid:9170 tgid:9167 ppid:5848 task_flags:0x40054c flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7238 irqentry_exit+0x599/0x620 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x7f/0x3d0 kernel/locking/lockdep.c:5881 Code: 26 3c 70 0e 00 0f 84 1c 02 00 00 65 8b 05 09 5e 7b 11 85 c0 0f 85 0d 02 00 00 65 4c 8b 3d 51 18 7b 11 41 83 bf 54 0b 00 00 00 <0f> 85 f7 01 00 00 49 81 3e 20 c4 e0 93 0f 84 ea 01 00 00 9c 5b fa RSP: 0018:ffffc900033d72d0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff90b36501 RCX: 0000000080000001 RDX: ffffc900033d7401 RSI: ffffffff8c27d860 RDI: ffffffff8c27d820 RBP: dffffc0000000000 R08: ffffc900033d78c8 R09: 0000000000000000 R10: ffffc900033d7458 R11: fffff5200067ae8d R12: ffffc900033d78d8 R13: ffffffff81769a55 R14: ffffffff8e75e5e0 R15: ffff88802e8dbd00 rcu_lock_release include/linux/rcupdate.h:319 [inline] rcu_read_unlock include/linux/rcupdate.h:878 [inline] class_rcu_destructor include/linux/rcupdate.h:1190 [inline] unwind_next_frame+0x1aaa/0x23c0 arch/x86/kernel/unwind_orc.c:695 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 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:1433 [inline] __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978 __slab_free+0x263/0x2b0 mm/slub.c:5573 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] __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5380 kmalloc_noprof include/linux/slab.h:950 [inline] kvm_uevent_notify_change+0x226/0x3a0 virt/kvm/kvm_main.c:6330 kvm_destroy_vm virt/kvm/kvm_main.c:1267 [inline] kvm_put_kvm+0xaa/0xa80 virt/kvm/kvm_main.c:1338 kvm_vm_release+0x43/0x50 virt/kvm/kvm_main.c:1361 __fput+0x44f/0xa70 fs/file_table.c:469 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x70f/0x23c0 kernel/exit.c:976 do_group_exit+0x21b/0x2d0 kernel/exit.c:1118 get_signal+0x1284/0x1330 kernel/signal.c:3034 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4f4c79c819 RSP: 002b:00007f4f4d656028 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: fffffffffffffe00 RBX: 00007f4f4ca16090 RCX: 00007f4f4c79c819 RDX: 000000000000fdef RSI: 0000200000000580 RDI: 000000000000000c RBP: 00007f4f4c832c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000010008095 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4f4ca16128 R14: 00007f4f4ca16090 R15: 00007f4f4cb3fa48 task:syz.1.820 state:R running task stack:25608 pid:9152 tgid:9148 ppid:5847 task_flags:0x40044c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7238 irqentry_exit+0x599/0x620 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:110 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:238 [inline] RIP: 0010:unwind_next_frame+0x2b4/0x23c0 arch/x86/kernel/unwind_orc.c:510 Code: 00 00 fc ff df 0f 84 1c 04 00 00 4a 8d 14 ad 54 30 24 90 45 29 e8 4a 8d 1c 82 48 83 c3 fc 49 89 d5 48 39 da 0f 86 21 02 00 00 <49> 29 d5 49 c1 fd 02 4a 8d 04 6d 00 00 00 00 4c 01 e8 48 8d 14 46 RSP: 0018:ffffc90003916b38 EFLAGS: 00000202 RAX: ffffffff9033f380 RBX: ffffffff9033f384 RCX: ffffffff9033f388 RDX: ffffffff9033f384 RSI: ffffffff90b4fe8c RDI: ffffffff8c27d820 RBP: ffffffff9033f388 R08: 0000000000000001 R09: ffffffff8e75e5e0 R10: ffffc90003916c58 R11: ffffffff81b0eba0 R12: ffffffff823a7760 R13: ffffffff9033f384 R14: ffffc90003916c08 R15: ffffffff9033f384 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 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:1433 [inline] free_unref_folios+0xed5/0x16d0 mm/page_alloc.c:3040 folios_put_refs+0x789/0x8d0 mm/swap.c:1002 free_pages_and_swap_cache+0x2e7/0x5b0 mm/swap_state.c:423 __tlb_batch_free_encoded_pages mm/mmu_gather.c:138 [inline] tlb_batch_pages_flush mm/mmu_gather.c:151 [inline] tlb_flush_mmu_free mm/mmu_gather.c:398 [inline] tlb_flush_mmu+0x6d3/0xa30 mm/mmu_gather.c:405 zap_pte_range mm/memory.c:1968 [inline] zap_pmd_range mm/memory.c:2021 [inline] zap_pud_range mm/memory.c:2049 [inline] zap_p4d_range mm/memory.c:2070 [inline] unmap_page_range+0x3c1d/0x48f0 mm/memory.c:2091 unmap_single_vma mm/memory.c:2133 [inline] unmap_vmas+0x48f/0x6a0 mm/memory.c:2171 exit_mmap+0x280/0xa10 mm/mmap.c:1302 __mmput+0x118/0x430 kernel/fork.c:1175 exit_mm+0x168/0x220 kernel/exit.c:581 do_exit+0x6a2/0x23c0 kernel/exit.c:964 do_group_exit+0x21b/0x2d0 kernel/exit.c:1118 get_signal+0x1284/0x1330 kernel/signal.c:3034 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0e3b99c819 RSP: 002b:00007f0e3c8f8028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: 0000000000010106 RBX: 00007f0e3bc16090 RCX: 00007f0e3b99c819 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007f0e3ba32c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0e3bc16128 R14: 00007f0e3bc16090 R15: 00007f0e3bd3fa48 task:syz-executor state:R running task stack:22496 pid:5847 tgid:5847 ppid:1 task_flags:0x40054c flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 preempt_schedule_notrace+0x57/0x90 kernel/sched/core.c:7188 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:753 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x57/0x2e0 kernel/locking/lockdep.c:5831 rcu_lock_acquire include/linux/rcupdate.h:309 [inline] rcu_read_lock include/linux/rcupdate.h:847 [inline] class_rcu_constructor include/linux/rcupdate.h:1190 [inline] unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 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:1433 [inline] __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978 vfree+0x25a/0x400 mm/vmalloc.c:3479 kcov_put kernel/kcov.c:442 [inline] kcov_close+0x28/0x50 kernel/kcov.c:543 __fput+0x44f/0xa70 fs/file_table.c:469 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x70f/0x23c0 kernel/exit.c:976 do_group_exit+0x21b/0x2d0 kernel/exit.c:1118 get_signal+0x1284/0x1330 kernel/signal.c:3034 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0e3b95d04e RSP: 002b:00007f0e3bd3fd28 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6 RAX: 0000000000000000 RBX: 000055557ecac500 RCX: 00007f0e3b95d04e RDX: 00007f0e3bd3fd80 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f0e3bd3fdec R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000000ae R13: 0000000000000063 R14: 000000000004327f R15: 00007f0e3bd3fe40 rcu: rcu_preempt kthread starved for 5424 jiffies! g39025 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:27616 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x164/0x360 kernel/sched/core.c:7008 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 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 0 to CPUs 1: NMI backtrace for cpu 1 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 03/18/2026 RIP: 0010:__lock_acquire+0x2be/0x2cf0 kernel/locking/lockdep.c:5170 Code: 24 18 0f 83 14 28 00 00 48 89 6c 24 28 48 8d 04 ad 00 00 00 00 48 01 e8 89 f1 81 e1 ff 1f 00 00 ba 00 e0 ff ff 41 23 54 c7 20 <09> ca 41 89 54 c7 20 4d 89 44 c7 08 4d 89 4c c7 10 48 8b 94 24 20 RSP: 0018:ffffc90000a077d8 EFLAGS: 00000006 RAX: 000000000000000f RBX: 0000000000000000 RCX: 0000000000000007 RDX: 0000000000022000 RSI: 0000000000000007 RDI: 0000000000000000 RBP: 0000000000000003 R08: ffffffff81769a55 R09: ffffffff8e75e5e0 R10: ffffc90000a07ab8 R11: ffffffff81b0eba0 R12: 0000000000000000 R13: 0000000000000002 R14: ffff88801dac0000 R15: ffff88801dac0b58 FS: 0000000000000000(0000) GS:ffff888125551000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000033b000 CR3: 00000000772e4000 CR4: 00000000003526f0 Call Trace: lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868 rcu_lock_acquire include/linux/rcupdate.h:309 [inline] rcu_read_lock include/linux/rcupdate.h:847 [inline] class_rcu_constructor include/linux/rcupdate.h:1190 [inline] unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4538 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4873 dst_alloc+0x105/0x170 net/core/dst.c:90 rt_dst_alloc net/ipv4/route.c:1651 [inline] __mkroute_output net/ipv4/route.c:2655 [inline] ip_route_output_key_hash_rcu+0x14d0/0x25d0 net/ipv4/route.c:2875 ip_route_output_key_hash+0x18d/0x2a0 net/ipv4/route.c:2705 __ip_route_output_key include/net/route.h:169 [inline] ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2932 ip_route_output_key include/net/route.h:179 [inline] ip_route_me_harder+0x742/0xf90 net/ipv4/netfilter.c:53 synproxy_send_tcp+0x34c/0x670 net/netfilter/nf_synproxy_core.c:432 synproxy_send_client_synack+0x8c1/0xe30 net/netfilter/nf_synproxy_core.c:485 nft_synproxy_eval_v4+0x34a/0x4e0 net/netfilter/nft_synproxy.c:60 nft_synproxy_do_eval+0x305/0x580 net/netfilter/nft_synproxy.c:142 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x45e/0x1990 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x29d/0x380 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+0x21f/0x3c0 include/linux/netfilter.h:316 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6181 [inline] __netif_receive_skb net/core/dev.c:6294 [inline] process_backlog+0xaa3/0x1950 net/core/dev.c:6645 __napi_poll+0xae/0x340 net/core/dev.c:7709 napi_poll net/core/dev.c:7772 [inline] net_rx_action+0x627/0xf70 net/core/dev.c:7929 handle_softirqs+0x22a/0x870 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 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:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: 1e 6b 02 c3 cc cc cc cc cc cc cc 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 a3 22 19 00 fb f4 fc e9 02 00 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffc90000197e20 EFLAGS: 00000242 RAX: 0000000000cfd5cb RBX: ffffffff819aac7a RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8defcc34 RDI: ffffffff8c27d880 RBP: ffffc90000197f10 R08: ffff8880b873399b R09: 1ffff110170e6733 R10: dffffc0000000000 R11: ffffed10170e6734 R12: 0000000000000001 R13: 1ffff11003b58000 R14: 0000000000000001 R15: 1ffff11003b58000 arch_safe_halt arch/x86/kernel/process.c:766 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x36a/0x5f0 kernel/sched/idle.c:352 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147