rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P18757 rcu: (detected by 0, t=10502 jiffies, g=108645, q=431 ncpus=2) task:syz.6.2654 state:R running task stack:25920 pid:18757 tgid:18756 ppid:18274 task_flags:0x400140 flags:0x00080000 Call Trace: sched_show_task+0x49d/0x630 kernel/sched/core.c:7822 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:292 [inline] print_other_cpu_stall+0xf7a/0x1340 kernel/rcu/tree_stall.h:681 check_cpu_stall kernel/rcu/tree_stall.h:856 [inline] rcu_pending kernel/rcu/tree.c:3667 [inline] rcu_sched_clock_irq+0xac1/0x1280 kernel/rcu/tree.c:2704 update_process_times+0x23c/0x2f0 kernel/time/timer.c:2474 tick_sched_handle kernel/time/tick-sched.c:298 [inline] tick_nohz_handler+0x3e9/0x710 kernel/time/tick-sched.c:319 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x4d0/0xc30 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:write_comp_data kernel/kcov.c:245 [inline] RIP: 0010:__sanitizer_cov_trace_cmp4+0x8/0x90 kernel/kcov.c:288 Code: 48 89 44 11 20 e9 18 e2 9e 09 cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 14 25 08 b0 9f 92 65 8b 0d f8 f5 dd 10 81 e1 00 01 ff 00 RSP: 0018:ffffc9000e7cf648 EFLAGS: 00000246 RAX: ffffffff894f9bbd RBX: 0000000000000000 RCX: ffff8880545c5b80 RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffea00020e7d80 R08: ffff888034f8458b R09: 1ffff110069f08b1 R10: dffffc0000000000 R11: ffffed10069f08b2 R12: ffff888034f84680 R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000002 netmem_is_pref_nid include/net/netmem.h:336 [inline] page_pool_refill_alloc_cache+0x31d/0x7e0 net/core/page_pool.c:406 __page_pool_get_cached net/core/page_pool.c:441 [inline] page_pool_alloc_netmems net/core/page_pool.c:659 [inline] page_pool_alloc_pages+0x129/0x200 net/core/page_pool.c:675 page_pool_dev_alloc_pages include/net/page_pool/helpers.h:96 [inline] xdp_test_run_batch net/bpf/test_run.c:295 [inline] bpf_test_run_xdp_live+0x646/0x1b20 net/bpf/test_run.c:379 bpf_prog_test_run_xdp+0x7c0/0x10e0 net/bpf/test_run.c:1388 bpf_prog_test_run+0x2c7/0x340 kernel/bpf/syscall.c:4704 __sys_bpf+0x5ee/0x8a0 kernel/bpf/syscall.c:6226 __do_sys_bpf kernel/bpf/syscall.c:6321 [inline] __se_sys_bpf kernel/bpf/syscall.c:6319 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6319 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb42918f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb429f74038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fb4293e5fa0 RCX: 00007fb42918f749 RDX: 0000000000000050 RSI: 0000200000000b80 RDI: 000000000000000a RBP: 00007fb429213f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb4293e6038 R14: 00007fb4293e5fa0 R15: 00007ffed01fc858 rcu: rcu_preempt kthread starved for 10542 jiffies! g108645 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:27104 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 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 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 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 33 9e 2a 00 f3 0f 1e fa fb f4 48 ee 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6 RAX: 002ba4bddd28dc00 RBX: ffffffff819786ba RCX: 002ba4bddd28dc00 RDX: 0000000000000001 RSI: ffffffff8d997e54 RDI: ffffffff8be07960 RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8fa22f70 R13: 1ffff11003ad4b70 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb4273f5f98 CR3: 0000000057c6a000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1ea/0x520 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147