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): P10261/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=47521, q=1974 ncpus=2)
task:syz.5.1129      state:R  running task     stack:24168 pid:10261 tgid:10261 ppid:9669   task_flags:0x400040 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6965
 preempt_schedule+0xae/0xc0 kernel/sched/core.c:6989
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 insert_page+0x189/0x2c0 mm/memory.c:2214
 kcov_mmap+0xc2/0x120 kernel/kcov.c:506
 call_mmap include/linux/fs.h:2282 [inline]
 mmap_file mm/internal.h:167 [inline]
 __mmap_new_file_vma mm/vma.c:2398 [inline]
 __mmap_new_vma mm/vma.c:2460 [inline]
 __mmap_region mm/vma.c:2615 [inline]
 mmap_region+0x1221/0x1f30 mm/vma.c:2685
 do_mmap+0xc45/0x10d0 mm/mmap.c:561
 vm_mmap_pgoff+0x31b/0x4c0 mm/util.c:579
 ksys_mmap_pgoff+0x51f/0x760 mm/mmap.c:607
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7e22f8e963
RSP: 002b:00007f7e232dfaf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f7e231b63b8 RCX: 00007f7e22f8e963
RDX: 0000000000000003 RSI: 0000000000400000 RDI: 00007f7e205f4000
RBP: 00007f7e231b6320 R08: 00000000000000dc R09: 0000000000000000
R10: 0000000000000011 R11: 0000000000000246 R12: 00007f7e231b5fa0
R13: 00007f7e231b6320 R14: 00000000000015b4 R15: 0000000000000003
 </TASK>
rcu: rcu_preempt kthread starved for 8104 jiffies! g47521 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
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:27128 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.15.0-syzkaller-11802-g1af80d00e1e0 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:ip6t_do_table+0x284/0x1560 net/ipv6/netfilter/ip6_tables.c:285
Code: d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 12 0e f4 f7 45 89 f6 49 c1 e6 03 4c 03 33 4c 89 f0 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 f7 e8 f2 0d f4 f7 49 8b 06 48 89 44 24 48 0f 1f 44 00
RSP: 0018:ffffc90000007400 EFLAGS: 00000246
RAX: 1ffff1100f026a04 RBX: ffff8880325c8038 RCX: 36c67640fcaee000
RDX: 0000000000000100 RSI: ffffffff8be27220 RDI: ffffffff8be271e0
RBP: ffffc900000075f0 R08: ffffc9000000756f R09: 0000000000000000
R10: ffffc90000007550 R11: fffff52000000eae R12: ffffc900000077e0
R13: dffffc0000000000 R14: ffff888078135020 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888125c5c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f38b5716965 CR3: 000000007f214000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000b5f DR2: 0000000000003706
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 ip6table_mangle_hook+0x2a2/0x6c0 net/ipv6/netfilter/ip6table_mangle.c:73
 nf_hook_entry_hookfn include/linux/netfilter.h:157 [inline]
 nf_hook_slow+0xc2/0x220 net/netfilter/core.c:623
 nf_hook include/linux/netfilter.h:272 [inline]
 NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:315
 ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:491
 NF_HOOK+0x309/0x3a0 include/linux/netfilter.h:317
 __netif_receive_skb_one_core net/core/dev.c:5977 [inline]
 __netif_receive_skb+0xd3/0x380 net/core/dev.c:6090
 process_backlog+0x60e/0x14f0 net/core/dev.c:6442
 __napi_poll+0xc7/0x480 net/core/dev.c:7414
 napi_poll net/core/dev.c:7478 [inline]
 net_rx_action+0x707/0xe30 net/core/dev.c:7605
 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:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 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:82
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 a3 75 23 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8de07d80 EFLAGS: 000002c2
RAX: 36c67640fcaee000 RBX: ffffffff81976078 RCX: 36c67640fcaee000
RDX: 0000000000000001 RSI: ffffffff8d979f2e RDI: ffffffff8be27240
RBP: ffffffff8de07ea8 R08: ffff8880b8632f5b R09: 1ffff110170c65eb
R10: dffffc0000000000 R11: ffffed10170c65ec R12: ffffffff8fa0f5f0
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a50
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:743
 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
 rest_init+0x2de/0x300 init/main.c:744
 start_kernel+0x47d/0x500 init/main.c:1101
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288
 common_startup_64+0x13e/0x147
 </TASK>