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): P14508/1:b..l rcu: (detected by 0, t=10502 jiffies, g=77577, q=1002430 ncpus=1) task:syz-executor state:R running task stack:28280 pid:14508 tgid:14508 ppid:5608 task_flags:0x400040 flags:0x00080000 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:lock_release+0x19e/0x310 kernel/locking/lockdep.c:5893 Code: ff 65 0f c1 05 a3 cb 7e 12 83 f8 01 0f 85 27 01 00 00 9c 58 f6 c4 02 0f 85 12 01 00 00 41 f7 c6 00 02 00 00 0f 85 c8 00 00 00 <48> 8b 44 24 10 65 48 2b 05 ad 84 7e 12 0f 85 4d 01 00 00 48 83 c4 RSP: 0018:ffffc900059377e0 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffffffff8ebe8200 RCX: ffffc900059377ec RDX: 0000000000000002 RSI: ffffffff8e1823aa RDI: ffffffff8c402680 RBP: ffffffff81b866be R08: 0000000000000001 R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000017abe R12: ffff88802abba540 R13: ffffc90005937898 R14: 0000000000000202 R15: 0000000000000003 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0x3c3/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5334 [inline] __kmalloc_node_track_caller_noprof+0x331/0x830 mm/slub.c:5471 kmemdup_noprof+0x29/0x60 mm/util.c:138 kmemdup_noprof include/linux/fortify-string.h:715 [inline] shmem_symlink+0x28d/0xa00 mm/shmem.c:4055 vfs_symlink fs/namei.c:5660 [inline] vfs_symlink+0x178/0x4d0 fs/namei.c:5639 filename_symlinkat+0x2a6/0x560 fs/namei.c:5685 __do_sys_symlinkat fs/namei.c:5705 [inline] __se_sys_symlinkat fs/namei.c:5700 [inline] __x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5700 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: 0033:0x7fa130f9d197 RSP: 002b:00007ffdca049f58 EFLAGS: 00000202 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa130f9d197 RDX: 00007fa131035fdd RSI: 00000000ffffff9c RDI: 00007ffdca049ff0 RBP: 00007ffdca049f9c R08: 0000000000000001 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000002d0 R13: 00000000000927c0 R14: 0000000000079d74 R15: 00007ffdca049ff0 rcu: rcu_preempt kthread starved for 854 jiffies! g77577 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:27592 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: 3224 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:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 bb 8b 7e 12 83 f8 07 0f 87 da 00 00 00 48 0f a3 05 46 92 3c 0f 0f 82 ac 02 00 00 8b 35 0e c6 3c 0f 85 f6 0f 85 c7 00 00 00 <48> 8b 44 24 30 65 48 2b 05 5d 8b 7e 12 0f 85 ec 02 00 00 48 83 c4 RSP: 0018:ffffc90000007090 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8e1823aa RDI: ffffffff8c402680 RBP: ffffffff8ebe8200 R08: 00000000f501fefe R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888123dd8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f94ed9276f2 CR3: 00000000757d2000 CR4: 00000000003526f0 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:840 [inline] class_rcu_constructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2677 [inline] slab_free mm/slub.c:6377 [inline] kfree+0x22b/0x6c0 mm/slub.c:6692 skb_kfree_head net/core/skbuff.c:1083 [inline] skb_free_head+0xb9/0x160 net/core/skbuff.c:1095 skb_release_data+0x6c5/0x8e0 net/core/skbuff.c:1122 skb_release_all net/core/skbuff.c:1197 [inline] __kfree_skb net/core/skbuff.c:1211 [inline] consume_skb net/core/skbuff.c:1445 [inline] consume_skb+0xc4/0x110 net/core/skbuff.c:1439 nft_synproxy_eval_v4 net/netfilter/nft_synproxy.c:60 [inline] nft_synproxy_do_eval+0xa24/0xce0 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