rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7926 rcu: (detected by 0, t=10502 jiffies, g=24085, q=435 ncpus=2) task:syz.4.389 state:R running task stack:26688 pid:7926 tgid:7925 ppid:5838 task_flags:0x400140 flags:0x00080000 Call Trace: sched_show_task+0x4aa/0x5f0 kernel/sched/core.c:8139 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:292 [inline] print_other_cpu_stall+0xfca/0x1380 kernel/rcu/tree_stall.h:681 check_cpu_stall kernel/rcu/tree_stall.h:856 [inline] rcu_pending kernel/rcu/tree.c:3679 [inline] rcu_sched_clock_irq+0x939/0x1050 kernel/rcu/tree.c:2716 update_process_times+0x234/0x2d0 kernel/time/timer.c:2475 tick_sched_handle kernel/time/tick-sched.c:298 [inline] tick_nohz_handler+0x42b/0x770 kernel/time/tick-sched.c:319 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x3bc/0xb10 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x455/0x950 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:rcu_lock_acquire include/linux/rcupdate.h:300 [inline] RIP: 0010:rcu_read_lock include/linux/rcupdate.h:838 [inline] RIP: 0010:__local_bh_disable_ip+0x1f9/0x420 kernel/softirq.c:174 Code: 00 e8 8b dc 0b 00 65 8b 05 a4 7f ee 10 85 c0 0f 84 fa 00 00 00 e8 37 82 22 00 48 c7 c7 00 81 fc 8d 31 f6 31 d2 b9 02 00 00 00 <45> 31 c0 45 31 c9 53 e8 cb 8f 18 00 48 83 c4 08 e8 e2 89 ae 09 85 RSP: 0018:ffffc900057876b0 EFLAGS: 00000246 RAX: 0000000000000002 RBX: ffffffff8187deec RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8dfc8100 RBP: 0000000000000200 R08: ffffffff8187deec R09: ffffffff8de5f280 R10: ffffc900057879a0 R11: fffff52000af0f42 R12: ffff88802790c964 R13: dffffc0000000000 R14: 1ffff11004f2192c R15: ffff88802790c240 local_bh_disable include/linux/bottom_half.h:20 [inline] xdp_test_run_batch net/bpf/test_run.c:289 [inline] bpf_test_run_xdp_live+0x520/0x1cf0 net/bpf/test_run.c:379 bpf_prog_test_run_xdp+0x81c/0x1160 net/bpf/test_run.c:1430 bpf_prog_test_run+0x2cd/0x340 kernel/bpf/syscall.c:4742 __sys_bpf+0x643/0x950 kernel/bpf/syscall.c:6266 __do_sys_bpf kernel/bpf/syscall.c:6361 [inline] __se_sys_bpf kernel/bpf/syscall.c:6359 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6359 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2bc3abc819 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:00007f2bc1d16028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f2bc3d35fa0 RCX: 00007f2bc3abc819 RDX: 0000000000000050 RSI: 0000200000000180 RDI: 000000000000000a RBP: 00007f2bc3b52c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f2bc3d36038 R14: 00007f2bc3d35fa0 R15: 00007ffc12f6b938 rcu: rcu_preempt kthread timer wakeup didn't happen for 10448 jiffies! g24085 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=14606 rcu: rcu_preempt kthread starved for 10449 jiffies! g24085 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:27768 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x169e/0x54f0 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0x164/0x360 kernel/sched/core.c:7282 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11b0 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+0x514/0xb70 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_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: 8b 59 02 e9 43 c7 03 00 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 03 0b 13 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffc900001e7e20 EFLAGS: 00000242 RAX: 00000000000ed383 RBX: ffffffff8199860a RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d6509ce RDI: ffffffff8ba84960 RBP: ffffc900001e7f10 R08: ffff8880b8733e9b R09: 1ffff110170e67d3 R10: dffffc0000000000 R11: ffffed10170e67d4 R12: 0000000000000001 R13: 1ffff11003b50b88 R14: 0000000000000001 R15: 1ffff11003b50b88 FS: 0000000000000000(0000) GS:ffff888125fba000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fedf7d5fff8 CR3: 0000000032f64000 CR4: 00000000003526f0 DR0: fffffffffffffffd DR1: 00000000000001f8 DR2: 0000000000000002 DR3: 0000000000000001 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: 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