rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7097 rcu: (detected by 0, t=10502 jiffies, g=19977, q=1254 ncpus=2) task:syz.2.377 state:R running task stack:25176 pid:7097 tgid:7092 ppid:5606 task_flags:0x400140 flags:0x00080000 Call Trace: sched_show_task+0x4aa/0x5f0 kernel/sched/core.c:8184 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:292 [inline] print_other_cpu_stall+0xf7b/0x1310 kernel/rcu/tree_stall.h:680 check_cpu_stall kernel/rcu/tree_stall.h:855 [inline] rcu_pending kernel/rcu/tree.c:3708 [inline] rcu_sched_clock_irq+0x93d/0x1050 kernel/rcu/tree.c:2744 update_process_times+0x234/0x2d0 kernel/time/timer.c:2475 tick_sched_handle kernel/time/tick-sched.c:296 [inline] tick_nohz_handler+0x38f/0x6b0 kernel/time/tick-sched.c:317 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x3a0/0xaf0 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x44a/0x900 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5874 Code: ff ff ff e8 41 7a 90 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 0b b5 d4 10 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 28 78 ef RSP: 0018:ffffc9000d1f6c00 EFLAGS: 00000286 RAX: 834183d982722400 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 00000000f188ff2e RSI: ffffffff8d8bebe5 RDI: ffffffff8baa6380 RBP: ffffffff817691ff R08: ffffffff817691ff R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8dfc3080 R12: 0000000000000002 R13: ffffffff8dfc3080 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:840 [inline] class_rcu_constructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_dst_trace_buffer+0x108/0x5b0 net/core/dst.c:102 dst_release+0x28/0x1b0 net/core/dst.c:250 vti_xmit net/ipv4/ip_vti.c:228 [inline] vti_tunnel_xmit+0xffd/0x1a60 net/ipv4/ip_vti.c:307 __netdev_start_xmit include/linux/netdevice.h:5402 [inline] netdev_start_xmit include/linux/netdevice.h:5411 [inline] xmit_one net/core/dev.c:3890 [inline] dev_hard_start_xmit+0x2df/0x870 net/core/dev.c:3906 __dev_queue_xmit+0x1549/0x3890 net/core/dev.c:4873 dev_queue_xmit include/linux/netdevice.h:3442 [inline] __bpf_tx_skb net/core/filter.c:2156 [inline] __bpf_redirect_no_mac net/core/filter.c:2186 [inline] __bpf_redirect+0xaa0/0x1380 net/core/filter.c:2209 ____bpf_clone_redirect net/core/filter.c:2497 [inline] bpf_clone_redirect+0x319/0x4b0 net/core/filter.c:2460 bpf_prog_69c2527fbc57d46b+0x5f/0x68 bpf_dispatcher_nop_func include/linux/bpf.h:1454 [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:422 bpf_prog_test_run_skb+0xe35/0x2230 net/bpf/test_run.c:1225 bpf_prog_test_run+0x2cb/0x340 kernel/bpf/syscall.c:4859 __sys_bpf+0xa22/0xd90 kernel/bpf/syscall.c:6436 __do_sys_bpf kernel/bpf/syscall.c:6537 [inline] __se_sys_bpf kernel/bpf/syscall.c:6534 [inline] __x64_sys_bpf+0xba/0xd0 kernel/bpf/syscall.c:6534 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8a057bce59 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:00007f8a039ed028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f8a05a36090 RCX: 00007f8a057bce59 RDX: 0000000000000050 RSI: 0000200000002300 RDI: 000000000000000a RBP: 00007f8a05852e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8a05a36128 R14: 00007f8a05a36090 R15: 00007fff68601568 rcu: rcu_preempt kthread timer wakeup didn't happen for 10444 jiffies! g19977 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x1000 rcu: Possible timer handling issue on cpu=1 timer-softirq=7263 rcu: rcu_preempt kthread starved for 10445 jiffies! g19977 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x1000 ->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:D stack:27176 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x1709/0x5530 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule_rtlock+0x30/0x70 kernel/sched/core.c:7390 rtlock_slowlock_locked+0x35c5/0x3c20 kernel/locking/rtmutex.c:1895 rtlock_slowlock kernel/locking/rtmutex.c:1922 [inline] rtlock_lock kernel/locking/spinlock_rt.c:43 [inline] __rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline] rt_spin_lock+0x165/0x400 kernel/locking/spinlock_rt.c:57 spin_lock include/linux/spinlock_rt.h:45 [inline] get_from_partial_node+0x58/0x460 mm/slub.c:3845 get_from_partial mm/slub.c:3975 [inline] ___slab_alloc+0xc2/0x910 mm/slub.c:4487 slab_alloc_node mm/slub.c:4936 [inline] kmem_cache_alloc_noprof+0xf5/0x650 mm/slub.c:4959 kmem_alloc_batch lib/debugobjects.c:371 [inline] fill_pool+0x165/0x610 lib/debugobjects.c:420 debug_objects_fill_pool+0x63/0x80 lib/debugobjects.c:780 debug_object_assert_init+0x65/0x300 lib/debugobjects.c:1058 debug_timer_assert_init kernel/time/timer.c:803 [inline] debug_assert_init kernel/time/timer.c:848 [inline] __try_to_del_timer_sync kernel/time/timer.c:1457 [inline] __timer_delete_sync+0x247/0x600 kernel/time/timer.c:1621 schedule_timeout+0x15a/0x2c0 kernel/time/sleep_timeout.c:100 rcu_gp_fqs_loop+0x30c/0x11c0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 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 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: 6b 5f 02 c3 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 82 18 00 fb f4 cc cc 03 00 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffc900001e7e40 EFLAGS: 00000242 RAX: 0000000000039523 RBX: ffffffff8199365c RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d658ada RDI: ffffffff8baa6380 RBP: ffffc900001e7f10 R08: ffff8880b8733d5b R09: 1ffff110170e67ab R10: dffffc0000000000 R11: ffffed10170e67ac R12: 0000000000000000 R13: 1ffff11003b52ba0 R14: 1ffff9200003cfd0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888125fcd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f77a78b0fd9 CR3: 000000003eb68000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/kernel/process.c:767 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:768 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x1cc/0x540 kernel/sched/idle.c:355 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:454 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x157