rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10127 ticks this GP) idle=147c/1/0x4000000000000000 softirq=23481/23482 fqs=4 rcu: (t=10500 jiffies g=26149 q=319 ncpus=2) rcu: rcu_preempt kthread starved for 10490 jiffies! g26149 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:26952 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 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+0x313/0x1590 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 8599 Comm: syz.1.682 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148 Code: 40 22 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 c3 29 43 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80 RSP: 0018:ffffc9000ba5f878 EFLAGS: 000002d3 RAX: ffffffff813aa578 RBX: 0000000000000003 RCX: ffff888027423c00 RDX: 0000000000000000 RSI: ffffffff8acac960 RDI: ffffffff8b1c85a0 RBP: ffffc9000ba5f950 R08: ffffffff911c15d7 R09: 1ffffffff22382ba R10: dffffc0000000000 R11: fffffbfff22382bb R12: dffffc0000000000 R13: 0000000000000200 R14: 0000000000000003 R15: 1ffff9200174bf14 FS: 000055557a6d9500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000a00000 CR3: 00000000670bd000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000 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+0x61a/0x9d0 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/0x2c0 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+0x1f4/0x5e0 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+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f33ca39c799 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:00007ffe92d1c8e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 0000000000035500 RCX: 00007f33ca39c799 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f33ca61609c RBP: 0000000000000032 R08: 0000000000745ad1 R09: 0000000000000000 R10: 00007ffe92d1c9f0 R11: 0000000000000246 R12: 00007ffe92d1ca10 R13: 00007f33ca61609c R14: 0000000000035532 R15: 00007ffe92d1c9f0 CPU: 0 PID: 8602 Comm: syz.1.682 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x10/0x60 kernel/kcov.c:216 Code: 89 fb e8 13 00 00 00 48 8b 3d bc d4 03 0d 48 89 de 5b e9 33 5f 57 00 cc cc cc f3 0f 1e fa 48 8b 04 24 65 48 8b 0d 50 99 7c 7e <65> 8b 15 51 99 7c 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 RSP: 0018:ffffc90000005f80 EFLAGS: 00000246 RAX: ffffffff813b6c79 RBX: ffffc900000064f8 RCX: ffff88801b759e00 RDX: 0000000000000100 RSI: 0000000000000002 RDI: ffffc900000064f8 RBP: ffffc900000060b8 R08: ffff88801b759e00 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000100 R12: ffffc90000006068 R13: dffffc0000000000 R14: ffffc900000064f8 R15: ffffffff8f89fe6e FS: 00007f33cb2a26c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000100000001 CR3: 00000000670bd000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000008d24 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __read_once_word_nocheck+0x9/0x10 include/asm-generic/rwonce.h:66 deref_stack_reg arch/x86/kernel/unwind_orc.c:406 [inline] unwind_next_frame+0x15f9/0x2970 arch/x86/kernel/unwind_orc.c:585 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4b0 mm/slab.h:767 slab_alloc_node mm/slub.c:3495 [inline] slab_alloc mm/slub.c:3503 [inline] __kmem_cache_alloc_lru mm/slub.c:3510 [inline] kmem_cache_alloc+0x11a/0x2d0 mm/slub.c:3519 skb_clone+0x1eb/0x370 net/core/skbuff.c:1915 dev_queue_xmit_nit+0x24d/0xbb0 net/core/dev.c:2353 xmit_one net/core/dev.c:3628 [inline] dev_hard_start_xmit+0x148/0x740 net/core/dev.c:3648 sch_direct_xmit+0x25e/0x4c0 net/sched/sch_generic.c:345 __dev_xmit_skb net/core/dev.c:3869 [inline] __dev_queue_xmit+0x165d/0x3660 net/core/dev.c:4404 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+0xcec/0x11e0 net/ipv4/ip_output.c:235 NF_HOOK_COND include/linux/netfilter.h:293 [inline] ip_output+0x2a1/0x3b0 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+0x1049/0x1950 net/ipv4/ip_output.c:540 __tcp_transmit_skb+0x1d6b/0x33f0 net/ipv4/tcp_output.c:1425 tcp_validate_incoming+0xf13/0x2250 net/ipv4/tcp_input.c:5899 tcp_rcv_established+0x7de/0x1d20 net/ipv4/tcp_input.c:6164 tcp_v4_do_rcv+0x4ed/0xb80 net/ipv4/tcp_ipv4.c:1734 tcp_v4_rcv+0x23bf/0x2af0 net/ipv4/tcp_ipv4.c:2166 ip_protocol_deliver_rcu+0x20e/0x3f0 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x2ca/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+0xa4c/0xd70 net/ipv4/ip_input.c:639 ip_list_rcv+0x3f2/0x440 net/ipv4/ip_input.c:674 __netif_receive_skb_list_ptype net/core/dev.c:5677 [inline] __netif_receive_skb_list_core+0x583/0x750 net/core/dev.c:5725 __netif_receive_skb_list net/core/dev.c:5777 [inline] netif_receive_skb_list_internal+0x943/0xca0 net/core/dev.c:5868 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:575 [inline] napi_gro_receive+0x565/0xb00 net/core/gro.c:605 receive_buf+0x2203/0x3820 drivers/net/virtio_net.c:1870 virtnet_receive drivers/net/virtio_net.c:2155 [inline] virtnet_poll+0x5dd/0x1280 drivers/net/virtio_net.c:2229 __napi_poll+0xc0/0x460 net/core/dev.c:6638 napi_poll net/core/dev.c:6705 [inline] net_rx_action+0x616/0xc40 net/core/dev.c:6841 handle_softirqs+0x280/0x820 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:plist_check_prev_next lib/plist.c:35 [inline] RIP: 0010:plist_check_list+0x3e/0x240 lib/plist.c:48 Code: 00 00 00 00 fc ff df e8 c0 b2 12 f7 48 89 e8 48 c1 e8 03 48 89 44 24 10 80 3c 18 00 74 08 48 89 ef e8 96 e1 6a f7 4c 8b 75 00 <4d> 8d 7e 08 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 RSP: 0018:ffffc9000be87b58 EFLAGS: 00000246 RAX: 1ffff92000144a29 RBX: dffffc0000000000 RCX: 0000000000080000 RDX: ffffc9000e51f000 RSI: 0000000000016f03 RDI: 0000000000016f04 RBP: ffffc90000a25148 R08: ffff888027423c2b R09: 1ffff11004e84785 R10: dffffc0000000000 R11: ffffed1004e84786 R12: dffffc0000000000 R13: ffffc9000ba5fc80 R14: ffffc90000a25148 R15: ffffc90000a25108 __futex_unqueue+0xf0/0x160 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+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f33ca39c799 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:00007f33cb2a20e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f33ca616098 RCX: 00007f33ca39c799 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f33ca61609c RBP: 00007f33ca616090 R08: 0000000000745ad1 R09: 0000000000000000 R10: 0000000000000010 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f33ca616128 R14: 00007ffe92d1c6a0 R15: 00007ffe92d1c788