rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6039 rcu: (detected by 0, t=10502 jiffies, g=13273, q=819 ncpus=2) task:syz.2.85 state:R running task stack:26592 pid:6039 tgid:6038 ppid:5622 task_flags:0x400140 flags:0x00080000 Call Trace: sched_show_task+0x4aa/0x5f0 kernel/sched/core.c:8148 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:2032 [inline] __hrtimer_run_queues+0x3bc/0xb10 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x455/0x950 kernel/time/hrtimer.c:2215 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:674 RIP: 0010:__sanitizer_cov_trace_pc+0x51/0x80 kernel/kcov.c:222 Code: 00 89 d7 09 f7 74 11 85 f6 75 39 85 d2 74 35 83 b9 b4 16 00 00 00 74 2c 8b 91 90 16 00 00 83 fa 02 75 21 48 8b 91 98 16 00 00 <48> 8b 32 48 8d 7e 01 8b 89 94 16 00 00 48 39 cf 73 08 48 89 3a 48 RSP: 0018:ffffc90006487698 EFLAGS: 00000246 RAX: ffffffff89110994 RBX: ffff888042414038 RCX: ffff88802f040000 RDX: ffffc90004bd2000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90006487b50 R08: ffff88802f040000 R09: 0000000000000004 R10: 0000000000000100 R11: 0000000000000004 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffc90006487988 R15: 0000000000000002 xdp_return_buff+0x24/0x330 net/core/xdp.c:550 xdp_test_run_batch net/bpf/test_run.c:341 [inline] bpf_test_run_xdp_live+0xd6d/0x1cf0 net/bpf/test_run.c:379 bpf_prog_test_run_xdp+0x81c/0x1160 net/bpf/test_run.c:1465 bpf_prog_test_run+0x2cd/0x340 kernel/bpf/syscall.c:4747 __sys_bpf+0x643/0x950 kernel/bpf/syscall.c:6271 __do_sys_bpf kernel/bpf/syscall.c:6366 [inline] __se_sys_bpf kernel/bpf/syscall.c:6364 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6364 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: 0033:0x7f8c8d4acdd9 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:00007f8c8b706028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f8c8d725fa0 RCX: 00007f8c8d4acdd9 RDX: 0000000000000050 RSI: 0000200000000b80 RDI: 000000000000000a RBP: 00007f8c8d542d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8c8d726038 R14: 00007f8c8d725fa0 R15: 00007fff64868718 rcu: rcu_preempt kthread timer wakeup didn't happen for 10451 jiffies! g13273 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=4617 rcu: rcu_preempt kthread starved for 10452 jiffies! g13273 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0 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:26920 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f9/0x5500 kernel/sched/core.c:7197 __schedule_loop kernel/sched/core.c:7276 [inline] schedule+0x164/0x360 kernel/sched/core.c:7291 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: CPU: 0 UID: 0 PID: 6039 Comm: syz.2.85 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x51/0x80 kernel/kcov.c:222 Code: 00 89 d7 09 f7 74 11 85 f6 75 39 85 d2 74 35 83 b9 b4 16 00 00 00 74 2c 8b 91 90 16 00 00 83 fa 02 75 21 48 8b 91 98 16 00 00 <48> 8b 32 48 8d 7e 01 8b 89 94 16 00 00 48 39 cf 73 08 48 89 3a 48 RSP: 0018:ffffc90006487698 EFLAGS: 00000246 RAX: ffffffff89110994 RBX: ffff888042414038 RCX: ffff88802f040000 RDX: ffffc90004bd2000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90006487b50 R08: ffff88802f040000 R09: 0000000000000004 R10: 0000000000000100 R11: 0000000000000004 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffc90006487988 R15: 0000000000000002 FS: 00007f8c8b7066c0(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff2d7867dac CR3: 000000003f0a6000 CR4: 00000000003526f0 Call Trace: xdp_return_buff+0x24/0x330 net/core/xdp.c:550 xdp_test_run_batch net/bpf/test_run.c:341 [inline] bpf_test_run_xdp_live+0xd6d/0x1cf0 net/bpf/test_run.c:379 bpf_prog_test_run_xdp+0x81c/0x1160 net/bpf/test_run.c:1465 bpf_prog_test_run+0x2cd/0x340 kernel/bpf/syscall.c:4747 __sys_bpf+0x643/0x950 kernel/bpf/syscall.c:6271 __do_sys_bpf kernel/bpf/syscall.c:6366 [inline] __se_sys_bpf kernel/bpf/syscall.c:6364 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6364 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: 0033:0x7f8c8d4acdd9 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:00007f8c8b706028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f8c8d725fa0 RCX: 00007f8c8d4acdd9 RDX: 0000000000000050 RSI: 0000200000000b80 RDI: 000000000000000a RBP: 00007f8c8d542d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8c8d726038 R14: 00007f8c8d725fa0 R15: 00007fff64868718