sched: DL replenish lagged too much rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (2 ticks this GP) idle=481c/1/0x4000000000000000 softirq=17794/17794 fqs=0 rcu: (detected by 0, t=10502 jiffies, g=13305, q=273 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: ipv6_addrconf addrconf_dad_work RIP: 0010:__lock_acquire+0x307/0xd20 kernel/locking/lockdep.c:5180 Code: b7 d2 09 f2 41 83 e4 03 41 c1 e4 10 41 09 d4 8b 54 24 0c 83 e2 01 c1 e2 12 44 09 e2 41 c1 e6 14 41 09 d6 8b 54 24 10 c1 e2 13 e5 15 09 d5 09 cd 44 09 f5 41 89 6c c7 20 45 89 44 c7 24 4c 89 RSP: 0018:ffffc90000a08ad0 EFLAGS: 00000006 RAX: 0000000000000023 RBX: ffffffff99d23290 RCX: 0000000000000000 RDX: 0000000000080000 RSI: 0000000000004000 RDI: ffff88801cea0000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff84d0b90a R10: ffffc90000a08cb0 R11: fffff52000141198 R12: 0000000000004000 R13: 0000000000000000 R14: 0000000000044000 R15: ffff88801cea0af0 FS: 0000000000000000(0000) GS:ffff888125d15000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055cd12daf170 CR3: 000000000df36000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 debug_object_deactivate+0x9a/0x250 lib/debugobjects.c:873 debug_hrtimer_deactivate kernel/time/hrtimer.c:450 [inline] debug_deactivate+0x1d/0x200 kernel/time/hrtimer.c:490 __run_hrtimer kernel/time/hrtimer.c:1729 [inline] __hrtimer_run_queues+0x2b0/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:99 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline] RIP: 0010:unwind_next_frame+0x132f/0x2390 arch/x86/kernel/unwind_orc.c:494 Code: 00 00 fc ff df 0f b6 04 08 84 c0 75 27 49 63 07 4c 01 f8 49 8d 4f 04 4c 39 e0 48 0f 46 e9 49 8d 47 fc 48 0f 47 d8 4d 0f 46 ef <48> 39 dd 76 a2 e9 7b ef ff ff 44 89 f9 80 e1 07 80 c1 03 38 c1 7c RSP: 0018:ffffc90000126c58 EFLAGS: 00000297 RAX: ffffffff8fb41b44 RBX: ffffffff8fb41b48 RCX: ffffffff8fb41b4c RDX: ffffffff8fb41b10 RSI: ffffffff902e6a66 RDI: ffffffff8be33e20 RBP: ffffffff8fb41b4c R08: 0000000000000015 R09: ffffffff8172d195 R10: ffffc90000126d78 R11: ffffffff81ac4b00 R12: ffffffff81336f69 R13: ffffffff8fb41b48 R14: ffffc90000126d28 R15: ffffffff8fb41b48 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4376 [inline] __kmalloc_noprof+0x27a/0x4f0 mm/slub.c:4388 kmalloc_noprof include/linux/slab.h:909 [inline] kmalloc_array_noprof include/linux/slab.h:948 [inline] nsim_fib6_event_init drivers/net/netdevsim/fib.c:810 [inline] nsim_fib6_prepare_event drivers/net/netdevsim/fib.c:947 [inline] nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:1003 [inline] nsim_fib_event_nb+0x295/0x1080 drivers/net/netdevsim/fib.c:1043 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85 atomic_notifier_call_chain+0xda/0x180 kernel/notifier.c:223 call_fib_notifiers+0x31/0x60 net/core/fib_notifier.c:35 call_fib6_entry_notifiers net/ipv6/ip6_fib.c:409 [inline] fib6_add_rt2node+0x15fb/0x33a0 net/ipv6/ip6_fib.c:1244 fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1528 __ip6_ins_rt net/ipv6/route.c:1351 [inline] ip6_ins_rt+0xc8/0x120 net/ipv6/route.c:1361 __ipv6_ifa_notify+0x63f/0xac0 net/ipv6/addrconf.c:6283 ipv6_ifa_notify net/ipv6/addrconf.c:6322 [inline] addrconf_dad_completed+0x180/0xd60 net/ipv6/addrconf.c:4320 addrconf_dad_work+0xc36/0x14b0 net/ipv6/addrconf.c:-1 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g13305 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=4750 rcu: rcu_preempt kthread starved for 10502 jiffies! g13305 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:27224 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245