rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8005 rcu: (detected by 0, t=10502 jiffies, g=24221, q=697 ncpus=2) task:syz.2.836 state:R running task stack:25880 pid:8005 tgid:8002 ppid:5611 task_flags:0x400040 flags:0x00080000 Call Trace: sched_show_task+0x4aa/0x5f0 kernel/sched/core.c:8140 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:arch_stack_walk+0x7e/0x150 arch/x86/kernel/stacktrace.c:18 Code: 65 48 8b 05 ac 36 02 11 49 39 c4 74 0a 49 8b 8c 24 38 19 00 00 eb 03 48 89 e9 48 c7 45 d0 00 00 00 00 48 c7 45 c8 00 00 00 00 <48> c7 45 c0 00 00 00 00 48 c7 45 b8 00 00 00 00 48 c7 45 b0 00 00 RSP: 0018:ffffc90006776dc8 EFLAGS: 00000246 RAX: ffff8880217abd80 RBX: ffffc90006776e80 RCX: ffffc90006776e50 RDX: ffff8880217abd80 RSI: ffffc90006776e80 RDI: ffffffff81afbe80 RBP: ffffc90006776e50 R08: dffffc0000000000 R09: 0000000000000000 R10: ffffc90006776f00 R11: fffffbfff1f152df R12: ffff8880217abd80 R13: 0000000000000000 R14: ffffffff81afbe80 R15: 0000000000000000 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2700 [inline] slab_free mm/slub.c:6291 [inline] kfree+0x1c5/0x6c0 mm/slub.c:6606 skb_kfree_head net/core/skbuff.c:1075 [inline] skb_free_head net/core/skbuff.c:1087 [inline] skb_release_data+0x828/0xa60 net/core/skbuff.c:1114 skb_release_all net/core/skbuff.c:1189 [inline] __kfree_skb+0x5d/0x210 net/core/skbuff.c:1203 kfree_skb_reason include/linux/skbuff.h:1320 [inline] __tcf_kfree_skb_list+0x14b/0x300 net/sched/sch_generic.c:59 tcf_kfree_skb_list include/net/sch_generic.h:1184 [inline] __dev_xmit_skb net/core/dev.c:4301 [inline] __dev_queue_xmit+0x202f/0x3900 net/core/dev.c:4832 dev_queue_xmit include/linux/netdevice.h:3423 [inline] __bpf_tx_skb net/core/filter.c:2147 [inline] __bpf_redirect_common net/core/filter.c:2191 [inline] __bpf_redirect+0xcfb/0x13c0 net/core/filter.c:2198 ____bpf_clone_redirect net/core/filter.c:2488 [inline] bpf_clone_redirect+0x313/0x4b0 net/core/filter.c:2451 bpf_prog_1939c40fbf65037b+0x5f/0x68 bpf_dispatcher_nop_func include/linux/bpf.h:1407 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] bpf_test_run+0x354/0x830 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0xe2c/0x2260 net/bpf/test_run.c:1227 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: 0033:0x7f8d2da5cdd9 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:00007f8d2bc95028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f8d2dcd6090 RCX: 00007f8d2da5cdd9 RDX: 0000000000000050 RSI: 0000200000001a00 RDI: 000000000000000a RBP: 00007f8d2daf2d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8d2dcd6128 R14: 00007f8d2dcd6090 R15: 00007ffd3983cbe8 rcu: rcu_preempt kthread timer wakeup didn't happen for 10445 jiffies! g24221 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=10443 rcu: rcu_preempt kthread starved for 10446 jiffies! g24221 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:26920 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x169e/0x54f0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 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 04/18/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: 4b 65 02 e9 03 cc 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 43 bb 21 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: 000000000003ec0d RBX: ffffffff81996aea RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d624e13 RDI: ffffffff8ba86860 RBP: ffffc900001e7f10 R08: ffff8880b8733e9b R09: 1ffff110170e67d3 R10: dffffc0000000000 R11: ffffed10170e67d4 R12: 0000000000000001 R13: 1ffff11003b50b88 R14: 0000000000000001 R15: 1ffff11003b50b88 FS: 0000000000000000(0000) GS:ffff888126025000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc2dca47221 CR3: 0000000024ea2000 CR4: 00000000003526f0 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 ip6_tunnel: ip6gre1 xmit: Local address not yet configured!