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): P5610/1:b..l P16833/1:b..l rcu: (detected by 0, t=10502 jiffies, g=96125, q=949043 ncpus=1) task:syz.4.4845 state:R running task stack:22200 pid:16833 tgid:16833 ppid:5608 task_flags:0x40064c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa00 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:unwind_next_frame+0x14a3/0x2090 arch/x86/kernel/unwind_orc.c:532 Code: 48 c1 ef 03 0f b6 14 17 48 89 cf 83 e7 07 40 38 fe 40 0f 9e c7 40 84 f6 40 0f 95 c6 40 84 f7 75 17 83 e0 07 38 c2 40 0f 9e c6 <84> d2 0f 95 c0 40 84 c6 0f 84 57 fe ff ff 48 89 cf be 02 00 00 00 RSP: 0018:ffffc9000415ef30 EFLAGS: 00000297 RAX: 0000000000000007 RBX: 0000000000000001 RCX: ffffffff91c9a4ce RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: ffffc9000415efe8 R08: ffffffff91c9a4d2 R09: 0000000000000007 R10: 0000000000000200 R11: 000000000000f473 R12: ffffc9000415eff0 R13: ffffc9000415efa0 R14: 0000000000000003 R15: ffffc9000415f040 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x162/0x1e0 mm/page_owner.c:165 __reset_page_owner+0x84/0x190 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] free_unref_folios+0xa44/0x1710 mm/page_alloc.c:3011 folios_put_refs+0x585/0xaa0 mm/swap.c:1057 folio_batch_release include/linux/folio_batch.h:101 [inline] shmem_undo_range+0x5e5/0x1570 mm/shmem.c:1159 shmem_truncate_range mm/shmem.c:1287 [inline] shmem_evict_inode+0x3a5/0xbe0 mm/shmem.c:1417 evict+0x3c2/0xad0 fs/inode.c:825 iput_final fs/inode.c:2019 [inline] iput.part.0+0x989/0x1050 fs/inode.c:2068 iput+0x35/0x40 fs/inode.c:2034 dentry_unlink_inode+0x284/0x470 fs/dcache.c:479 dentry_kill+0x25d/0xc20 fs/dcache.c:826 finish_dput fs/dcache.c:1001 [inline] dput.part.0+0xd7/0x240 fs/dcache.c:1042 dput+0x1f/0x30 fs/dcache.c:1037 __fput+0x519/0xb50 fs/file_table.c:520 task_work_run+0x150/0x240 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x951/0x2ae0 kernel/exit.c:1009 do_group_exit+0xd5/0x2a0 kernel/exit.c:1152 get_signal+0x1ec7/0x21e0 kernel/signal.c:3046 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop kernel/entry/common.c:101 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline] irqentry_exit+0x402/0xa00 kernel/entry/common.c:165 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595 RIP: 0033:0x7f8d1b39e0e1 RSP: 002b:0000000000000050 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f8d1b625fa0 RCX: 00007f8d1b39e0d9 RDX: 0000000000000000 RSI: 0000000000000050 RDI: 0000000000000000 RBP: 00007f8d1b435024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8d1b626038 R14: 00007f8d1b625fa0 R15: 00007ffc9b19f198 task:syz-executor state:R running task stack:21416 pid:5610 tgid:5610 ppid:5602 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7413 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:190 spin_unlock include/linux/spinlock.h:390 [inline] copy_pte_range mm/memory.c:1347 [inline] copy_pmd_range mm/memory.c:1408 [inline] copy_pud_range mm/memory.c:1445 [inline] copy_p4d_range mm/memory.c:1469 [inline] copy_page_range+0x1c1f/0x5b20 mm/memory.c:1555 dup_mmap+0xd44/0x21b0 mm/mmap.c:1840 dup_mm kernel/fork.c:1543 [inline] copy_mm kernel/fork.c:1595 [inline] copy_process+0x4588/0x8030 kernel/fork.c:2289 kernel_clone+0x176/0x9d0 kernel/fork.c:2748 __do_sys_clone+0xd9/0x120 kernel/fork.c:2889 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f79851c6b52 RSP: 002b:00007ffed335f4a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffed335f4a0 RCX: 00007f79851c6b52 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffed335f62c R08: 0000000000000000 R09: 0000000000000001 R10: 00005555866fb7d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 00000000000553d2 R15: 00007ffed335f680 rcu: rcu_preempt kthread starved for 232 jiffies! g96125 f0x2 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:27672 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: CPU: 0 UID: 0 PID: 3225 Comm: kworker/R-bat_e Tainted: G L syzkaller #0 PREEMPT(lazy) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Workqueue: bat_events batadv_tt_purge RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x17/0x70 kernel/kcov.c:217 Code: 03 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 8b 05 45 1b 5a 12 48 8b 34 24 65 48 8b 15 21 1b 5a 12 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 e9 d1 0d RSP: 0018:ffffc90000006fe8 EFLAGS: 00000246 RAX: 0000000080000101 RBX: ffff888020e85e00 RCX: ffffffff8a42e08c RDX: ffff8880346f2540 RSI: ffffffff89a2ed9f RDI: ffff8880346f2540 RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffffc900000073c0 R14: ffff888026f27980 R15: 00000000ffffffff FS: 0000000000000000(0000) GS:ffff888123dd8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f14e8040111 CR3: 00000000765b4000 CR4: 00000000003526f0 Call Trace: fib_rule_match net/core/fib_rules.c:310 [inline] fib_rules_lookup+0x79f/0x1060 net/core/fib_rules.c:323 __fib_lookup+0xec/0x1e0 net/ipv4/fib_rules.c:96 fib_lookup.constprop.0+0x35b/0x4c0 include/net/ip_fib.h:381 ip_route_output_key_hash_rcu+0xde2/0x2870 net/ipv4/route.c:2809 ip_route_output_key_hash+0x118/0x2b0 net/ipv4/route.c:2700 __ip_route_output_key include/net/route.h:169 [inline] ip_route_output_flow+0x27/0x150 net/ipv4/route.c:2927 ip_route_output_key include/net/route.h:179 [inline] ip_route_me_harder+0x562/0x1260 net/ipv4/netfilter.c:54 synproxy_send_tcp.isra.0+0x341/0x680 net/netfilter/nf_synproxy_core.c:434 synproxy_send_client_synack+0x6ea/0x970 net/netfilter/nf_synproxy_core.c:487 nft_synproxy_eval_v4 net/netfilter/nft_synproxy.c:59 [inline] nft_synproxy_do_eval+0xa1c/0xce0 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x2e5/0x19d0 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0xf3/0x400 net/netfilter/nft_chain_filter.c:162 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xbf/0x220 net/netfilter/core.c:619 nf_hook.constprop.0+0x2a6/0x750 include/linux/netfilter.h:273 NF_HOOK include/linux/netfilter.h:316 [inline] ip_local_deliver+0x163/0x1f0 net/ipv4/ip_input.c:262 dst_input include/net/dst.h:480 [inline] ip_rcv_finish net/ipv4/ip_input.c:492 [inline] NF_HOOK include/linux/netfilter.h:318 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] ip_rcv+0x33a/0x3c0 net/ipv4/ip_input.c:612 __netif_receive_skb_one_core+0x197/0x1e0 net/core/dev.c:6212 __netif_receive_skb+0x1f/0x120 net/core/dev.c:6325 process_backlog+0x37a/0x1580 net/core/dev.c:6676 __napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7735 napi_poll net/core/dev.c:7798 [inline] net_rx_action+0xa40/0xf20 net/core/dev.c:7955 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622 do_softirq kernel/softirq.c:523 [inline] do_softirq+0xac/0xe0 kernel/softirq.c:510 __local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] batadv_tt_global_purge net/batman-adv/translation-table.c:2301 [inline] batadv_tt_purge+0x25d/0xbd0 net/batman-adv/translation-table.c:3566 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] rescuer_thread+0x905/0x14a0 kernel/workqueue.c:3629 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245