rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (1 GPs behind) idle=752c/1/0x4000000000000000 softirq=37366/37369 fqs=23 rcu: (t=10502 jiffies g=45869 q=233 ncpus=2) rcu: rcu_preempt kthread starved for 10457 jiffies! g45869 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:26504 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 12072 Comm: syz.2.2061 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148 Code: dc 23 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 43 67 44 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2c 89 cb 80 f9 RSP: 0018:ffffc90019b6f878 EFLAGS: 000002d3 RAX: ffffffff813a9538 RBX: 0000000000000003 RCX: ffff8880325c0000 RDX: 0000000000000000 RSI: ffffffff8acacb60 RDI: ffffffff8b1c7be0 RBP: ffffc90019b6f950 R08: ffffffff911bc5ff R09: 1ffffffff22378bf R10: dffffc0000000000 R11: fffffbfff22378c0 R12: dffffc0000000000 R13: 0000000000000200 R14: 0000000000000003 R15: 1ffff9200336df14 FS: 0000555568e1b500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2d90eff8 CR3: 0000000077b15000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000200000000300 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline] kvm_wait+0x23d/0x2a0 arch/x86/kernel/kvm.c:1058 pv_wait arch/x86/include/asm/paravirt.h:598 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline] __pv_queued_spin_lock_slowpath+0x613/0x9c0 kernel/locking/qspinlock.c:511 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:586 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x23e/0x2b0 kernel/locking/spinlock_debug.c:115 spin_lock include/linux/spinlock.h:351 [inline] futex_unqueue+0x4e/0xf0 kernel/futex/core.c:597 futex_wait+0x1f1/0x5c0 kernel/futex/waitwake.c:660 do_futex+0x2ff/0x3e0 kernel/futex/syscalls.c:134 __do_sys_futex kernel/futex/syscalls.c:211 [inline] __se_sys_futex+0x3a9/0x440 kernel/futex/syscalls.c:192 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fae7499ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc40aa4c58 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 0000000000056237 RCX: 00007fae7499ce59 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fae74c15fac RBP: 0000000000000032 R08: 0000000000745b0f R09: 0000000000000000 R10: 00007ffc40aa4d60 R11: 0000000000000246 R12: 00007ffc40aa4d80 R13: 00007fae74c15fac R14: 0000000000056269 R15: 00007ffc40aa4d60 CPU: 1 PID: 12073 Comm: syz.2.2061 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__list_del_entry_valid_or_report+0x0/0x130 lib/list_debug.c:46 Code: 48 89 d9 e8 62 09 48 06 0f 0b 48 c7 c7 20 7e 1c 8b 48 89 de 4c 89 f1 e8 4e 09 48 06 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 66 90 0f 1e fa 41 57 41 56 41 54 53 48 89 fb 49 bc 00 00 00 00 00 fc RSP: 0018:ffffc900001eec30 EFLAGS: 00000246 RAX: ffffea0000b11108 RBX: 1ffff110171e843e RCX: ffff8880b8f421f8 RDX: 0000000000000001 RSI: 0000000000000002 RDI: ffffea0000b11108 RBP: ffff88813fffad40 R08: dffffc0000000000 R09: 0000000000000002 R10: 0000000000000000 R11: fffffbfff22378a1 R12: ffffea0000b11108 R13: ffff8880b8f421f0 R14: dead000000000100 R15: ffff8880b8f42180 FS: 00007fae757cd6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000100000000 CR3: 0000000077b15000 CR4: 00000000003506e0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000200000000300 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __list_del_entry_valid include/linux/list.h:124 [inline] __list_del_entry include/linux/list.h:215 [inline] list_del include/linux/list.h:229 [inline] __rmqueue_pcplist+0x105c/0x1580 mm/page_alloc.c:2762 rmqueue_pcplist mm/page_alloc.c:2794 [inline] rmqueue mm/page_alloc.c:2831 [inline] get_page_from_freelist+0x670/0x22a0 mm/page_alloc.c:3218 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4501 __stack_depot_save+0x42c/0x660 lib/stackdepot.c:410 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_set_track+0x5f/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1811 [inline] slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837 slab_free mm/slub.c:3830 [inline] __kmem_cache_free+0xba/0x1f0 mm/slub.c:3843 skb_kfree_head net/core/skbuff.c:946 [inline] skb_free_head net/core/skbuff.c:958 [inline] skb_release_data+0x609/0x7f0 net/core/skbuff.c:988 skb_release_all net/core/skbuff.c:1054 [inline] __kfree_skb net/core/skbuff.c:1068 [inline] kfree_skb_reason+0x10e/0x170 net/core/skbuff.c:1104 dev_kfree_skb_any_reason+0x120/0x130 net/core/dev.c:3241 free_old_xmit_skbs+0x11a/0x3b0 drivers/net/virtio_net.c:780 start_xmit+0x16d/0x1470 drivers/net/virtio_net.c:2420 __netdev_start_xmit include/linux/netdevice.h:4943 [inline] netdev_start_xmit include/linux/netdevice.h:4957 [inline] xmit_one net/core/dev.c:3644 [inline] dev_hard_start_xmit+0x269/0x790 net/core/dev.c:3660 sch_direct_xmit+0x251/0x4a0 net/sched/sch_generic.c:345 __dev_xmit_skb net/core/dev.c:3881 [inline] __dev_queue_xmit+0x162a/0x3630 net/core/dev.c:4416 dev_queue_xmit include/linux/netdevice.h:3113 [inline] neigh_hh_output include/net/neighbour.h:527 [inline] neigh_output include/net/neighbour.h:541 [inline] ip_finish_output2+0xd4f/0x1260 net/ipv4/ip_output.c:235 NF_HOOK_COND include/linux/netfilter.h:293 [inline] ip_output+0x2a5/0x3a0 net/ipv4/ip_output.c:436 dst_output include/net/dst.h:467 [inline] ip_local_out net/ipv4/ip_output.c:129 [inline] __ip_queue_xmit+0x1056/0x1960 net/ipv4/ip_output.c:540 __tcp_transmit_skb+0x1dd6/0x3470 net/ipv4/tcp_output.c:1427 tcp_ack_snd_check net/ipv4/tcp_input.c:5738 [inline] tcp_rcv_established+0xb22/0x1d70 net/ipv4/tcp_input.c:6184 tcp_v4_do_rcv+0x6d3/0xba0 net/ipv4/tcp_ipv4.c:1735 tcp_v4_rcv+0x2358/0x2a60 net/ipv4/tcp_ipv4.c:2167 ip_protocol_deliver_rcu+0x20a/0x3f0 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x2c3/0x510 net/ipv4/ip_input.c:233 NF_HOOK+0x32d/0x3b0 include/linux/netfilter.h:304 dst_input include/net/dst.h:477 [inline] ip_sublist_rcv_finish net/ipv4/ip_input.c:580 [inline] ip_list_rcv_finish net/ipv4/ip_input.c:631 [inline] ip_sublist_rcv+0xa36/0xd60 net/ipv4/ip_input.c:639 ip_list_rcv+0x3ed/0x440 net/ipv4/ip_input.c:674 __netif_receive_skb_list_ptype net/core/dev.c:5689 [inline] __netif_receive_skb_list_core+0x582/0x770 net/core/dev.c:5737 __netif_receive_skb_list net/core/dev.c:5789 [inline] netif_receive_skb_list_internal+0x943/0xca0 net/core/dev.c:5880 gro_normal_list include/net/gro.h:451 [inline] gro_normal_one include/net/gro.h:464 [inline] napi_skb_finish net/core/gro.c:580 [inline] napi_gro_receive+0x553/0xaf0 net/core/gro.c:610 receive_buf+0x219d/0x37a0 drivers/net/virtio_net.c:1870 virtnet_receive drivers/net/virtio_net.c:2155 [inline] virtnet_poll+0x60e/0x11e0 drivers/net/virtio_net.c:2229 __napi_poll+0xbb/0x460 net/core/dev.c:6650 napi_poll net/core/dev.c:6717 [inline] net_rx_action+0x65f/0xcc0 net/core/dev.c:6853 handle_softirqs+0x27d/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:__sanitizer_cov_trace_pc+0x3b/0x60 kernel/kcov.c:219 Code: 8b 15 e1 d2 7c 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 83 fa 02 75 21 <48> 8b 91 00 16 00 00 48 8b 32 48 8d 7e 01 8b 89 fc 15 00 00 48 39 RSP: 0018:ffffc90019c0fb08 EFLAGS: 00000246 RAX: ffffffff8a733c32 RBX: ffffc90019b6fc68 RCX: ffff888019fdbc00 RDX: 0000000000000002 RSI: 0000000000019ec0 RDI: 0000000000019ec1 RBP: ffffc90000a2c1c8 R08: ffff8880325c002b R09: 1ffff110064b8005 R10: dffffc0000000000 R11: ffffed10064b8006 R12: ffffc90000a2c1c8 R13: ffffc90000a2c1d0 R14: ffffc90019b6fc68 R15: dffffc0000000000 plist_check_prev_next lib/plist.c:35 [inline] plist_check_list+0x212/0x240 lib/plist.c:52 plist_check_head lib/plist.c:60 [inline] plist_del+0x69/0x3c0 lib/plist.c:114 __futex_unqueue+0xeb/0x150 kernel/futex/core.c:518 futex_wake_mark+0xec/0x150 kernel/futex/waitwake.c:123 futex_wake+0x32f/0x4f0 kernel/futex/waitwake.c:177 do_futex+0x35d/0x3e0 kernel/futex/syscalls.c:139 __do_sys_futex kernel/futex/syscalls.c:211 [inline] __se_sys_futex+0x3a9/0x440 kernel/futex/syscalls.c:192 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fae7499ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fae757cd0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007fae74c15fa8 RCX: 00007fae7499ce59 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fae74c15fac RBP: 00007fae74c15fa0 R08: 0000000000745b0f R09: 0000000000000000 R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fae74c16038 R14: 00007ffc40aa4a10 R15: 00007ffc40aa4af8