rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P23533 rcu: (detected by 0, t=10502 jiffies, g=107069, q=602321 ncpus=2) task:syz.2.4301 state:R running task stack:21768 pid:23533 tgid:23530 ppid:22187 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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:198 Code: f7 e8 ad 2d 81 f6 f7 c3 00 02 00 00 74 05 e8 20 d2 ac f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 54 bd 73 f6 65 8b 05 dd 92 4a 07 85 c0 74 18 5b 41 5e e9 01 3c RSP: 0018:ffffc90004d36440 EFLAGS: 00000206 RAX: 0000000000000002 RBX: 0000000000000292 RCX: 0000000080000001 RDX: 0000000000000002 RSI: ffffffff8d603a74 RDI: 0000000000000001 RBP: 0000000000000000 R08: ffffffff8f88dbf7 R09: 1ffffffff1f11b7e R10: dffffc0000000000 R11: fffffbfff1f11b7f R12: dffffc0000000000 R13: 1ffff1102f988b4b R14: ffffffff99a7d2e0 R15: ffff88817cc42600 debug_rcu_head_queue kernel/rcu/rcu.h:237 [inline] __call_rcu_common kernel/rcu/tree.c:3116 [inline] call_rcu+0x5b/0x890 kernel/rcu/tree.c:3251 refdst_drop include/net/dst.h:272 [inline] skb_dst_drop include/net/dst.h:284 [inline] skb_release_head_state+0x71/0x360 net/core/skbuff.c:1163 skb_release_all net/core/skbuff.c:1187 [inline] __kfree_skb+0x24/0x210 net/core/skbuff.c:1203 kfree_skb_reason include/linux/skbuff.h:1322 [inline] kfree_skb include/linux/skbuff.h:1331 [inline] ip_tunnel_xmit+0xfe1/0x1f20 net/ipv4/ip_tunnel.c:-1 __gre_xmit+0x19e/0x240 net/ipv4/ip_gre.c:491 erspan_xmit+0xa41/0x14d0 net/ipv4/ip_gre.c:750 __netdev_start_xmit include/linux/netdevice.h:5368 [inline] netdev_start_xmit include/linux/netdevice.h:5377 [inline] xmit_one net/core/dev.c:3888 [inline] dev_hard_start_xmit+0x2df/0x860 net/core/dev.c:3904 sch_direct_xmit+0x251/0x4c0 net/sched/sch_generic.c:372 __dev_xmit_skb net/core/dev.c:4209 [inline] __dev_queue_xmit+0x171e/0x3900 net/core/dev.c:4831 dev_queue_xmit include/linux/netdevice.h:3418 [inline] neigh_hh_output include/net/neighbour.h:540 [inline] neigh_output include/net/neighbour.h:554 [inline] ip_finish_output2+0xcab/0x10b0 net/ipv4/ip_output.c:237 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_output+0x29f/0x450 net/ipv4/ip_output.c:438 iptunnel_xmit+0x654/0xda0 net/ipv4/ip_tunnel_core.c:97 ip_tunnel_xmit+0x193d/0x1f20 net/ipv4/ip_tunnel.c:845 __gre_xmit net/ipv4/ip_gre.c:491 [inline] ipgre_xmit+0x8e6/0xc70 net/ipv4/ip_gre.c:695 __netdev_start_xmit include/linux/netdevice.h:5368 [inline] netdev_start_xmit include/linux/netdevice.h:5377 [inline] xmit_one net/core/dev.c:3888 [inline] dev_hard_start_xmit+0x2df/0x860 net/core/dev.c:3904 __dev_queue_xmit+0x1428/0x3900 net/core/dev.c:4870 dev_queue_xmit include/linux/netdevice.h:3418 [inline] __bpf_tx_skb net/core/filter.c:2147 [inline] __bpf_redirect_no_mac net/core/filter.c:2177 [inline] __bpf_redirect+0xaef/0x13c0 net/core/filter.c:2200 ____bpf_clone_redirect net/core/filter.c:2488 [inline] bpf_clone_redirect+0x313/0x4b0 net/core/filter.c:2451 bpf_prog_3e1cbbed0c4acd81+0x5f/0x68 bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline] __bpf_prog_run include/linux/filter.h:722 [inline] bpf_prog_run include/linux/filter.h:729 [inline] bpf_test_run+0x354/0x830 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0xe2c/0x2260 net/bpf/test_run.c:1192 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: 0033:0x7fe78aa7cdd9 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:00007fe788c8c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fe78acf6180 RCX: 00007fe78aa7cdd9 RDX: 0000000000000050 RSI: 00002000000000c0 RDI: 000000000000000a RBP: 00007fe78ab12d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe78acf6218 R14: 00007fe78acf6180 R15: 00007fff7873d658 rcu: rcu_preempt kthread timer wakeup didn't happen for 220 jiffies! g107069 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=79755 rcu: rcu_preempt kthread starved for 221 jiffies! g107069 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:26976 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x1681/0x54c0 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+0x312/0x11d0 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: 7b 6e 02 e9 43 c8 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 63 2b 2d 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: 0000:ffffc900001d7e20 EFLAGS: 00000246 RAX: 0000000001a7918d RBX: ffffffff819953aa RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d603a74 RDI: ffffffff8ba74ce0 RBP: ffffc900001d7f10 R08: ffff8880b8933e9b R09: 1ffff110171267d3 R10: dffffc0000000000 R11: ffffed10171267d4 R12: 0000000000000001 R13: 1ffff11003a51000 R14: 0000000000000001 R15: 1ffff11003a51000 FS: 0000000000000000(0000) GS:ffff88812627a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6315efe175 CR3: 0000000035e26000 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