sched: DL replenish lagged too much rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5804/1:b..l rcu: (detected by 0, t=10502 jiffies, g=124009, q=134 ncpus=2) task:syz-executor state:R running task stack:21912 pid:5804 tgid:5804 ppid:5803 task_flags:0x400100 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x168f/0x4c70 kernel/sched/core.c:6767 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7090 irqentry_exit+0x6f/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5870 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 4b 02 d4 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90003fbf238 EFLAGS: 00000206 RAX: fcc22b1d8ad46c00 RBX: 0000000000000000 RCX: fcc22b1d8ad46c00 RDX: 0000000000000000 RSI: ffffffff8d921248 RDI: ffffffff8bc0fe60 RBP: ffffffff8171a9f5 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8171a9f5 R12: 0000000000000002 R13: ffffffff8df3b860 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf7/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0xb05/0xcd0 mm/page_alloc.c:2725 discard_slab mm/slub.c:2716 [inline] __put_partials+0x161/0x1c0 mm/slub.c:3185 put_cpu_partial+0x17c/0x250 mm/slub.c:3260 __slab_free+0x2f7/0x400 mm/slub.c:4512 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4147 [inline] slab_alloc_node mm/slub.c:4196 [inline] __do_kmalloc_node mm/slub.c:4326 [inline] __kmalloc_noprof+0x224/0x4f0 mm/slub.c:4339 kmalloc_noprof include/linux/slab.h:909 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] lsm_blob_alloc security/security.c:684 [inline] lsm_cred_alloc security/security.c:701 [inline] security_prepare_creds+0x52/0x390 security/security.c:3241 prepare_creds+0x497/0x6c0 kernel/cred.c:242 copy_creds+0x106/0xa10 kernel/cred.c:312 copy_process+0x95d/0x3b80 kernel/fork.c:2293 kernel_clone+0x224/0x7f0 kernel/fork.c:2844 __do_sys_clone3 kernel/fork.c:3148 [inline] __se_sys_clone3+0x256/0x2d0 kernel/fork.c:3127 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc6f35c31c9 RSP: 002b:00007ffdd8fdb1d8 EFLAGS: 00000202 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00007fc6f358cb70 RCX: 00007fc6f35c31c9 RDX: 00007fc6f358cb70 RSI: 0000000000000058 RDI: 00007ffdd8fdb240 RBP: 00007ffdd8fdb2a0 R08: 00007ffdd8fdb2a0 R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000202 R12: ffffffffffffffa8 R13: 000000000000000b R14: 00007ffdd8fdb240 R15: 00007ffdd8fdb710 rcu: rcu_preempt kthread starved for 9686 jiffies! g124009 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:27032 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x168f/0x4c70 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2248 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 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 6.15.0-rc5-syzkaller-00043-gd76bb1ebb558 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025 RIP: 0010:__find_rr_leaf+0x12d/0x6d0 net/ipv6/route.c:838 Code: 44 24 68 4c 89 7c 24 30 4d 85 ff 74 3c 49 8d 9e 90 00 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 7e 03 00 00 8b 1b <89> df 44 8b 64 24 44 44 89 e6 e8 04 c8 b7 f7 44 39 e3 0f 85 07 04 RSP: 0018:ffffc90000a081a0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000100 RCX: ffff88801c6cda00 RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000a082f8 R08: ffffc90000a08420 R09: ffffc90000a08430 R10: ffffc90000a08280 R11: fffff52000141052 R12: 1ffff1100a52000c R13: dffffc0000000000 R14: ffff888029045c00 R15: ffffc90000a083f8 FS: 0000000000000000(0000) GS:ffff8881261fe000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f95d6265b1a CR3: 000000003303c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: find_rr_leaf net/ipv6/route.c:890 [inline] rt6_select net/ipv6/route.c:934 [inline] fib6_table_lookup+0x39f/0xa80 net/ipv6/route.c:2230 ip6_pol_route+0x222/0x1180 net/ipv6/route.c:2266 pol_lookup_func include/net/ip6_fib.h:616 [inline] fib6_rule_lookup+0x52f/0x6f0 net/ipv6/fib6_rules.c:120 ip6_route_input_lookup net/ipv6/route.c:2335 [inline] ip6_route_input+0x6ce/0xa50 net/ipv6/route.c:2631 ip6_rcv_finish+0x141/0x2d0 net/ipv6/ip6_input.c:77 NF_HOOK+0x309/0x3a0 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5887 [inline] __netif_receive_skb+0xd3/0x380 net/core/dev.c:6000 process_backlog+0x60e/0x14f0 net/core/dev.c:6352 __napi_poll+0xc4/0x480 net/core/dev.c:7324 napi_poll net/core/dev.c:7388 [inline] net_rx_action+0x6ea/0xdf0 net/core/dev.c:7510 handle_softirqs+0x283/0x870 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81 Code: 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 03 fb 18 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6 RAX: f9847a64348e8500 RBX: ffffffff81974e48 RCX: f9847a64348e8500 RDX: 0000000000000001 RSI: ffffffff8d737203 RDI: ffffffff8bc0fe60 RBP: ffffc90000197f20 R08: ffff8880b8932b5b R09: 1ffff1101712656b R10: dffffc0000000000 R11: ffffed101712656c R12: ffffffff8f7daf70 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110038d9b40 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:748 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x1e8/0x510 kernel/sched/idle.c:325 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147