rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P25481 (detected by 0, t=10502 jiffies, g=108637, q=972) task:syz.7.6215 state:R running task stack:24272 pid:25481 ppid: 24689 flags:0x0000400c Call Trace: sched_show_task+0x459/0x580 kernel/sched/core.c:8659 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:233 [inline] print_other_cpu_stall+0xec5/0x1270 kernel/rcu/tree_stall.h:573 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x845/0x1120 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:2021 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:__lt_find include/linux/rbtree_latch.h:113 [inline] RIP: 0010:latch_tree_find include/linux/rbtree_latch.h:208 [inline] RIP: 0010:bpf_ksym_find kernel/bpf/core.c:692 [inline] RIP: 0010:is_bpf_text_address+0x17f/0x270 kernel/bpf/core.c:726 Code: 39 df 73 47 e8 12 d0 f3 ff b8 08 00 00 00 49 01 c6 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 04 15 39 00 4d 8b 36 <4d> 85 f6 74 0a e8 e7 cf f3 ff e9 5a ff ff ff e8 dd cf f3 ff 31 ed RSP: 0018:ffffc90000006700 EFLAGS: 00000246 RAX: 1ffffffff1a89f9c RBX: 00007fdbc7f98159 RCX: ffff888025bc0000 RDX: 0000000000000100 RSI: 00007fdbc7f98159 RDI: ffffffffa002e000 RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff2042818 R10: dffffc0000000000 R11: fffffbfff2042819 R12: dffffc0000000000 R13: 0000000000000000 R14: 0000000000000000 R15: ffffffffa002e000 kernel_text_address kernel/extable.c:151 [inline] __kernel_text_address+0x9a/0x100 kernel/extable.c:105 unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323 arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc+0xaf/0xe0 mm/kasan/common.c:522 kmalloc_reserve net/core/skbuff.c:356 [inline] __alloc_skb+0x22c/0x750 net/core/skbuff.c:427 alloc_skb_fclone include/linux/skbuff.h:1212 [inline] sk_stream_alloc_skb+0x204/0xb50 net/ipv4/tcp.c:892 tso_fragment net/ipv4/tcp_output.c:2131 [inline] tcp_write_xmit+0x111e/0x65c0 net/ipv4/tcp_output.c:2704 __tcp_push_pending_frames+0x92/0x250 net/ipv4/tcp_output.c:2903 tcp_push_pending_frames include/net/tcp.h:1918 [inline] tcp_data_snd_check net/ipv4/tcp_input.c:5572 [inline] tcp_rcv_established+0xff2/0x1de0 net/ipv4/tcp_input.c:5984 tcp_v4_do_rcv+0x435/0x9b0 net/ipv4/tcp_ipv4.c:1738 tcp_v4_rcv+0x276f/0x2da0 net/ipv4/tcp_ipv4.c:2150 ip_protocol_deliver_rcu+0x38c/0x740 net/ipv4/ip_input.c:204 ip_local_deliver_finish+0x1d8/0x320 net/ipv4/ip_input.c:231 NF_HOOK+0x303/0x390 include/linux/netfilter.h:302 dst_input include/net/dst.h:462 [inline] ip_sublist_rcv_finish net/ipv4/ip_input.c:577 [inline] ip_list_rcv_finish net/ipv4/ip_input.c:628 [inline] ip_sublist_rcv+0xa1b/0xd10 net/ipv4/ip_input.c:636 ip_list_rcv+0x3e9/0x440 net/ipv4/ip_input.c:671 __netif_receive_skb_list_ptype net/core/dev.c:5594 [inline] __netif_receive_skb_list_core+0x2d5/0x770 net/core/dev.c:5632 __netif_receive_skb_list net/core/dev.c:5694 [inline] netif_receive_skb_list_internal+0x898/0xbd0 net/core/dev.c:5785 gro_normal_list net/core/dev.c:5939 [inline] gro_normal_one net/core/dev.c:5952 [inline] napi_skb_finish net/core/dev.c:6289 [inline] napi_gro_receive+0x4eb/0xa60 net/core/dev.c:6319 receive_buf+0x39de/0x59d0 drivers/net/virtio_net.c:1240 virtnet_receive drivers/net/virtio_net.c:1504 [inline] virtnet_poll+0x5ce/0xfb0 drivers/net/virtio_net.c:1620 __napi_poll+0xbb/0x430 net/core/dev.c:7101 napi_poll net/core/dev.c:7168 [inline] net_rx_action+0x522/0xa80 net/core/dev.c:7258 handle_softirqs+0x336/0x830 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 common_interrupt+0xb5/0xd0 arch/x86/kernel/irq.c:242 asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667 RIP: 0010:lock_acquire+0x209/0x400 kernel/locking/lockdep.c:5741 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25 RSP: 0018:ffffc9000357f240 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 65685d14e588fd00 RDX: 0000000000000000 RSI: ffffffff8a2b3e80 RDI: ffffffff8a7a4b80 RBP: ffffc9000357f360 R08: dffffc0000000000 R09: 1ffffffff2042818 R10: dffffc0000000000 R11: fffffbfff2042819 R12: 1ffff920006afe54 R13: ffffffff8c31efa0 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313 rcu_read_lock include/linux/rcupdate.h:740 [inline] is_bpf_text_address+0x1d/0x270 kernel/bpf/core.c:725 kernel_text_address kernel/extable.c:151 [inline] __kernel_text_address+0x9a/0x100 kernel/extable.c:105 unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323 arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0x92/0xc0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3225 [inline] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc+0x15d/0x280 mm/slub.c:3238 skb_clone+0x1bd/0x350 net/core/skbuff.c:1527 ____bpf_clone_redirect net/core/filter.c:2456 [inline] bpf_clone_redirect+0x166/0x460 net/core/filter.c:2434 bpf_prog_6893982b85ceadf7+0x56/0x6c8 bpf_dispatcher_nop_func include/linux/bpf.h:890 [inline] __bpf_prog_run include/linux/filter.h:621 [inline] bpf_prog_run include/linux/filter.h:635 [inline] bpf_test_run+0x4ae/0x800 net/bpf/test_run.c:119 bpf_prog_test_run_skb+0x9fb/0x1190 net/bpf/test_run.c:678 bpf_prog_test_run+0x31c/0x390 kernel/bpf/syscall.c:3374 __sys_bpf+0x5a5/0x6f0 kernel/bpf/syscall.c:4675 __do_sys_bpf kernel/bpf/syscall.c:4761 [inline] __se_sys_bpf kernel/bpf/syscall.c:4759 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fdbc7f98159 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:00007fdbc61f0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fdbc821ffa0 RCX: 00007fdbc7f98159 RDX: 000000000000002c RSI: 0000200000000080 RDI: 000000000000000a RBP: 00007fdbc802f06b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdbc8220038 R14: 00007fdbc821ffa0 R15: 00007ffde49b55f8 rcu: rcu_preempt kthread timer wakeup didn't happen for 7661 jiffies! g108637 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=42528 rcu: rcu_preempt kthread starved for 7667 jiffies! g108637 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27504 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11c3/0x4350 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11f0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 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: 0 Comm: swapper/1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] RIP: 0010:kvm_wait+0x159/0x1b0 arch/x86/kernel/kvm.c:918 Code: 89 df 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 4b 0f b6 1f e8 47 a5 4a 00 44 38 e3 75 10 66 90 0f 00 2d 89 d9 f3 08 fb f4 16 ff ff ff fb e9 10 ff ff ff e8 b7 6c 8d 08 89 f9 80 e1 07 38 RSP: 0018:ffffc90000dd08a0 EFLAGS: 00000246 RAX: 568a172e7fd69f00 RBX: 0000000000000003 RCX: 568a172e7fd69f00 RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4b80 RBP: ffffc90000dd0950 R08: ffffffff9021418f R09: 1ffffffff2042831 R10: dffffc0000000000 R11: fffffbfff2042832 R12: 0000000000000003 R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff920001ba114 FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fff0e20cbb0 CR3: 0000000073eca000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: pv_wait arch/x86/include/asm/paravirt.h:597 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline] __pv_queued_spin_lock_slowpath+0x605/0x9b0 kernel/locking/qspinlock.c:508 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline] queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline] do_raw_spin_lock+0x265/0x2f0 kernel/locking/spinlock_debug.c:115 spin_lock include/linux/spinlock.h:364 [inline] tcp_write_timer+0x29/0x280 net/ipv4/tcp_timer.c:673 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648 expire_timers kernel/time/timer.c:1699 [inline] __run_timers+0x56c/0x810 kernel/time/timer.c:1970 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983 handle_softirqs+0x336/0x830 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:730 Code: b7 48 89 df e8 c6 fc f2 f7 eb ad e8 af aa f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 00 cc 66 90 0f 00 2d 37 62 5a 00 fb f4 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48 RSP: 0018:ffffc90000d67d48 EFLAGS: 000002c2 RAX: 568a172e7fd69f00 RBX: ffff88813fe68000 RCX: 568a172e7fd69f00 RDX: 0000000000000001 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4b80 RBP: ffffc90000d67e80 R08: ffff8880b913b30b R09: 1ffff11017227661 R10: dffffc0000000000 R11: ffffed1017227662 R12: 1ffff920001acfb4 R13: dffffc0000000000 R14: 1ffff11027fcd000 R15: 0000000000000000 default_idle_call+0x81/0xc0 kernel/sched/idle.c:112 cpuidle_idle_call kernel/sched/idle.c:202 [inline] do_idle+0x251/0x650 kernel/sched/idle.c:326 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:424 start_secondary+0x32f/0x430 arch/x86/kernel/smpboot.c:281 secondary_startup_64_no_verify+0xb1/0xbb