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): P14443/1:b..l rcu: (detected by 0, t=10502 jiffies, g=132449, q=1429 ncpus=1) task:syz.1.2136 state:R running task stack:26888 pid:14443 tgid:14421 ppid:5616 task_flags:0x40044c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x1b2a/0x59a0 kernel/sched/core.c:7232 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7554 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x910 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:kasan_check_range+0x1d1/0x2c0 mm/kasan/generic.c:200 Code: 24 07 4d 85 e4 49 0f 49 dc 48 83 e3 f8 49 29 dc 74 0e 41 80 3b 00 75 7c 49 ff c3 49 ff cc 75 f2 5b 41 5c 41 5d 41 5e 41 5f 5d cc cc cc cc cc 45 84 ff 0f 85 a1 00 00 00 41 f7 c7 00 ff 00 00 RSP: 0018:ffffc90004fc70d0 EFLAGS: 00000256 RAX: 1ffffffff3503e01 RBX: ffff88801dd430b8 RCX: ffffffff82421bb5 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88801dd430b8 RBP: 0000000000000000 R08: ffff88801dd430bb R09: 1ffff11003ba8617 R10: dffffc0000000000 R11: ffffed1003ba8618 R12: 0000000000000001 R13: ffff88801dd43070 R14: 0000000000000000 R15: 0000000000000001 instrument_atomic_read include/linux/instrumented.h:82 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline] __page_table_check_zero+0x1b5/0x430 mm/page_table_check.c:142 page_table_check_free include/linux/page_table_check.h:46 [inline] __free_pages_prepare mm/page_alloc.c:1419 [inline] free_unref_folios+0xdd2/0x14e0 mm/page_alloc.c:3080 folios_put_refs+0x9e9/0xb30 mm/folio.c:1034 folio_batch_release include/linux/folio_batch.h:101 [inline] shmem_undo_range+0x4e6/0x15d0 mm/shmem.c:1160 shmem_truncate_range mm/shmem.c:1288 [inline] shmem_evict_inode+0x247/0xae0 mm/shmem.c:1419 evict+0x624/0xb50 fs/inode.c:822 dentry_kill+0x1b9/0x880 fs/dcache.c:826 finish_dput+0x1a/0x260 fs/dcache.c:1001 __fput+0x675/0xa50 fs/file_table.c:520 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x73a/0x2360 kernel/exit.c:1008 do_group_exit+0x22d/0x2f0 kernel/exit.c:1151 get_signal+0x121b/0x12c0 kernel/signal.c:3039 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x138/0x770 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline] do_syscall_64+0x328/0x510 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f328679e0d9 RSP: 002b:00007f328765d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f3286a26098 RCX: 00007f328679e0d9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3286a26098 RBP: 00007f3286a26090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3286a26128 R14: 00007ffd5bb9cc40 R15: 00007ffd5bb9cd28 rcu: rcu_preempt kthread starved for 370 jiffies! g132449 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27496 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x1b2a/0x59a0 kernel/sched/core.c:7232 __schedule_loop kernel/sched/core.c:7309 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7324 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 3227 Comm: kworker/R-bat_e Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: bat_events batadv_tt_purge RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] RIP: 0010:rcu_is_watching+0x2e/0xb0 kernel/rcu/tree.c:753 Code: 41 57 41 56 53 65 ff 05 a0 1f c5 11 e8 1b 31 2f 0a 89 c3 83 f8 08 73 65 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd d0 37 52 8e <4c> 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 fc 27 8a 00 RSP: 0018:ffffc900000076a0 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000080000102 RDX: 00000000e61b7dd1 RSI: ffffffff8c4c7660 RDI: ffffffff8c4c7620 RBP: 1ffff92000000ef4 R08: 9800000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8eb5c6a0 R12: dffffc0000000000 R13: ffffffff8177ccef R14: ffffffff8e5237d0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888124f0c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f17d1116f19 CR3: 000000007f8ba000 CR4: 00000000003526f0 Call Trace: rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1216 [inline] unwind_next_frame+0xbe/0x2550 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6499 [inline] kmem_cache_free+0x182/0x650 mm/slub.c:6626 skb_ext_reset include/linux/skbuff.h:5117 [inline] skb_release_head_state+0x270/0x360 net/core/skbuff.c:1189 skb_release_all net/core/skbuff.c:1195 [inline] __kfree_skb+0x24/0x210 net/core/skbuff.c:1211 can_receive+0x366/0x440 net/can/af_can.c:679 canfd_rcv+0x1f9/0x330 net/can/af_can.c:715 __netif_receive_skb_one_core net/core/dev.c:6241 [inline] __netif_receive_skb net/core/dev.c:6354 [inline] process_backlog+0xbf0/0x1860 net/core/dev.c:6705 __napi_poll+0xaa/0x330 net/core/dev.c:7764 napi_poll net/core/dev.c:7827 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:7984 handle_softirqs+0x225/0x840 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] batadv_tt_local_purge+0x2c1/0x340 net/batman-adv/translation-table.c:1366 batadv_tt_purge+0x35/0xa10 net/batman-adv/translation-table.c:3565 process_one_work kernel/workqueue.c:3375 [inline] process_scheduled_works+0xc4e/0x1630 kernel/workqueue.c:3458 rescuer_thread+0x7c5/0x10e0 kernel/workqueue.c:3682 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245