rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P18208 rcu: (detected by 0, t=10502 jiffies, g=91837, q=547 ncpus=2) task:syz.7.3135 state:R running task stack:23872 pid:18208 tgid:18206 ppid:17762 task_flags:0x400140 flags:0x00080000 Call Trace: sched_show_task+0x49d/0x630 kernel/sched/core.c:7819 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+0x9a9/0x1140 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:INET_ECN_set_ce include/net/inet_ecn.h:174 [inline] RIP: 0010:____bpf_skb_ecn_set_ce net/core/filter.c:7496 [inline] RIP: 0010:bpf_skb_ecn_set_ce+0x95b/0x10c0 net/core/filter.c:7475 Code: ff 45 31 e4 e9 c4 fe ff ff e8 71 93 7d f8 4c 8b 7c 24 18 41 0f b7 dc 48 89 df 48 c7 c6 90 6b 31 8f e8 d9 98 7d f8 66 83 fb 08 <0f> 84 a0 00 00 00 81 fb 86 dd 00 00 0f 85 32 01 00 00 49 8d bf d0 RSP: 0018:ffffc90003d6f800 EFLAGS: 00000246 RAX: 0000000000000002 RBX: 0000000000000008 RCX: 0000000000000003 RDX: ffffffff89436597 RSI: ffffffff8f316b90 RDI: 0000000000000008 RBP: ffffc90003d6f920 R08: ffff88801abddb80 R09: 0000000000000002 R10: 000000000000dd86 R11: 0000000000000002 R12: 0000000000000008 R13: 00000000ffffffee R14: 0000000000000012 R15: ffff888031818500 bpf_prog_7ef7b2538d944267+0x1b/0x21 bpf_dispatcher_nop_func include/linux/bpf.h:1378 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] bpf_test_run+0x313/0x7d0 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0xd67/0x1d50 net/bpf/test_run.c:1158 bpf_prog_test_run+0x2c7/0x340 kernel/bpf/syscall.c:4703 __sys_bpf+0x562/0x860 kernel/bpf/syscall.c:6182 __do_sys_bpf kernel/bpf/syscall.c:6274 [inline] __se_sys_bpf kernel/bpf/syscall.c:6272 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6272 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2b8c18f749 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:00007f2b8cf4d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f2b8c3e5fa0 RCX: 00007f2b8c18f749 RDX: 0000000000000050 RSI: 0000200000000880 RDI: 000000000000000a RBP: 00007f2b8c213f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f2b8c3e6038 R14: 00007f2b8c3e5fa0 R15: 00007ffdbad7c398 rcu: rcu_preempt kthread starved for 10177 jiffies! g91837 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:27648 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 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+0x510/0xa50 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: 1e 14 b6 f5 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 53 21 0e 00 f3 0f 1e fa fb f4 f3 13 b6 f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197e20 EFLAGS: 000002c6 RAX: 0000000001e2807d RBX: ffffffff8197149e RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d793aa5 RDI: ffffffff8bc08760 RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8f823070 R13: 1ffff110038d6b70 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125f1b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb275a5ed10 CR3: 000000001d304000 CR4: 0000000000350ef0 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+0x1be/0x4d0 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