IPVS: fo: UDP 224.0.0.2:0 - no destination available rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4185/1:b..l (detected by 1, t=10502 jiffies, g=33125, q=267) task:syz-executor state:R running task stack:21520 pid: 4185 ppid: 4178 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:lock_release+0x584/0x870 kernel/locking/lockdep.c:5647 Code: 00 00 00 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 75 75 f7 44 24 50 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 2f 00 00 00 00 66 43 c7 44 2f 09 00 00 43 c6 44 2f 0b 00 RSP: 0018:ffffc90002f5f8c0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 9be2421a50ef4013 RCX: 29a3c4853548e000 RDX: 0000000000000001 RSI: ffffffff8a0b2e80 RDI: ffffffff8a59e800 RBP: ffffc90002f5f9d8 R08: dffffc0000000000 R09: fffffbfff1ad26b6 R10: fffffbfff1ad26b6 R11: 1ffffffff1ad26b5 R12: ffff888075bd4698 R13: dffffc0000000000 R14: ffff888075bd4660 R15: 1ffff920005ebf24 rcu_read_unlock include/linux/rcupdate.h:773 [inline] percpu_ref_tryget_many include/linux/percpu-refcount.h:250 [inline] percpu_ref_tryget+0xcf/0x150 include/linux/percpu-refcount.h:266 obj_cgroup_tryget include/linux/memcontrol.h:800 [inline] get_obj_cgroup_from_current mm/memcontrol.c:2930 [inline] __memcg_kmem_charge_page+0x230/0x380 mm/memcontrol.c:3056 memcg_kmem_charge_page include/linux/memcontrol.h:1696 [inline] memcg_charge_kernel_stack kernel/fork.c:417 [inline] dup_task_struct+0x913/0xb30 kernel/fork.c:903 copy_process+0x5b3/0x3e00 kernel/fork.c:2121 kernel_clone+0x219/0x930 kernel/fork.c:2679 __do_sys_clone kernel/fork.c:2796 [inline] __se_sys_clone kernel/fork.c:2780 [inline] __x64_sys_clone+0x170/0x1c0 kernel/fork.c:2780 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f1b2caeee93 RSP: 002b:00007ffdcd3c1a38 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1b2caeee93 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000555592aad7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 000000000003d4e9 R15: 00007ffdcd3c1bd0 rcu: rcu_preempt kthread starved for 10494 jiffies! g33125 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:27808 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 4283 Comm: kworker/1:9 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: events fqdir_free_fn Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_single+0x212/0x490 kernel/smp.c:758 Code: 48 44 89 f6 83 e6 01 31 ff e8 ca 5e 0b 00 41 83 e6 01 49 bc 00 00 00 00 00 fc ff df 75 0a e8 55 5b 0b 00 e9 a3 00 00 00 f3 90 44 24 48 01 00 00 00 0f 84 8e 00 00 00 e8 3b 5b 0b 00 eb e9 e8 RSP: 0018:ffffc90004c87a40 EFLAGS: 00000293 RAX: ffffffff816c70d5 RBX: 0000000000000000 RCX: ffff88802bd09dc0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90004c87b30 R08: dffffc0000000000 R09: ffffed1017207681 R10: ffffed1017207681 R11: 1ffff11017207680 R12: dffffc0000000000 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff92000990f4c rcu_barrier+0x25d/0x4b0 kernel/rcu/tree.c:4082 fqdir_free_fn+0x2f/0x130 net/ipv4/inet_fragment.c:166 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287