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): P28451/1:b..l rcu: (detected by 0, t=10509 jiffies, g=134549, q=130 ncpus=2) task:syz.6.5680 state:R running task stack:26568 pid:28451 tgid:28450 ppid:18045 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_is_held_type+0x5/0x190 kernel/locking/lockdep.c:5925 Code: 04 48 c7 c6 cf 30 91 8d 67 48 0f b9 3a 90 eb bb e8 50 fc ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 <41> 57 41 56 41 55 41 54 53 48 83 ec 10 65 48 8b 05 66 eb 22 07 48 RSP: 0018:ffffc9000f2a7598 EFLAGS: 00000202 RAX: 1ffffffff1be8d01 RBX: ffffffff826450ac RCX: 20895acc1c28df00 RDX: ffff88802633bd00 RSI: 00000000ffffffff RDI: ffffffff8df41a20 RBP: 0000000000000001 R08: ffffffff826450ac R09: ffffffff8df41a20 R10: dffffc0000000000 R11: ffffed102808a038 R12: dffffc0000000000 R13: ffff8880406d6ad0 R14: ffff8880406d6c30 R15: ffff8880406d6a50 kernfs_root+0xf6/0x230 fs/kernfs/kernfs-internal.h:76 kernfs_link_sibling+0x396/0x3e0 fs/kernfs/dir.c:398 kernfs_add_one+0x1ca/0x5c0 fs/kernfs/dir.c:813 __kernfs_create_file+0x22b/0x2e0 fs/kernfs/file.c:1086 sysfs_add_file_mode_ns+0x238/0x300 fs/sysfs/file.c:313 create_files fs/sysfs/group.c:82 [inline] internal_create_group+0x667/0x1170 fs/sysfs/group.c:189 internal_create_groups fs/sysfs/group.c:229 [inline] sysfs_create_groups+0x59/0x120 fs/sysfs/group.c:255 rx_queue_add_kobject net/core/net-sysfs.c:1266 [inline] net_rx_queue_update_kobjects+0x283/0x740 net/core/net-sysfs.c:1322 register_queue_kobjects net/core/net-sysfs.c:2114 [inline] netdev_register_kobject+0x21f/0x310 net/core/net-sysfs.c:2362 register_netdevice+0x1246/0x1a70 net/core/dev.c:11391 register_netdev+0x40/0x60 net/core/dev.c:11507 loopback_net_init+0x75/0x150 drivers/net/loopback.c:218 ops_init+0x35c/0x5c0 net/core/net_namespace.c:137 setup_net+0x110/0x330 net/core/net_namespace.c:446 copy_net_ns+0x3e3/0x570 net/core/net_namespace.c:581 create_new_namespaces+0x3e7/0x6a0 kernel/nsproxy.c:130 unshare_nsproxy_namespaces+0x11c/0x170 kernel/nsproxy.c:226 ksys_unshare+0x4c8/0x8c0 kernel/fork.c:3171 __do_sys_unshare kernel/fork.c:3242 [inline] __se_sys_unshare kernel/fork.c:3240 [inline] __x64_sys_unshare+0x38/0x50 kernel/fork.c:3240 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff6f518f749 RSP: 002b:00007ff6f60c4038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007ff6f53e5fa0 RCX: 00007ff6f518f749 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000006a040000 RBP: 00007ff6f5213f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff6f53e6038 R14: 00007ff6f53e5fa0 R15: 00007ffc889bf7d8 rcu: rcu_preempt kthread starved for 10509 jiffies! g134549 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:27136 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 28320 Comm: syz.4.5644 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194 Code: 74 05 e8 7b 2a 6b f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 53 ae 32 f6 65 8b 05 ec 50 20 07 85 c0 74 40 48 c7 04 24 0e 36 RSP: 0018:ffffc90000007b00 EFLAGS: 00000206 RAX: ebf0482494a6c600 RBX: 0000000000000a06 RCX: ebf0482494a6c600 RDX: 0000000000000002 RSI: ffffffff8d7925e3 RDI: 0000000000000001 RBP: ffffc90000007b90 R08: ffffffff8f822077 R09: 1ffffffff1f0440e R10: dffffc0000000000 R11: fffffbfff1f0440f R12: dffffc0000000000 R13: ffffffff99c40ec0 R14: ffffffff8f038ac0 R15: 1ffff92000000f60 FS: 0000000000000000(0000) GS:ffff888125e35000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c357ecc CR3: 0000000077858000 CR4: 00000000003526f0 Call Trace: call_timer_fn+0x16e/0x590 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2373 [inline] __run_timer_base+0x61a/0x860 kernel/time/timer.c:2385 run_timer_base kernel/time/timer.c:2394 [inline] run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2404 handle_softirqs+0x27d/0x850 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:unwind_next_frame+0x4b6/0x23d0 arch/x86/kernel/unwind_orc.c:520 Code: 4c 89 e8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 80 18 00 00 41 0f b6 44 24 01 83 e0 07 0f 84 6d 15 00 00 83 f8 01 4c 8b 7c 24 50 <48> bd 00 00 00 00 00 fc ff df 4c 8b 64 24 20 4c 8b 6c 24 48 0f 84 RSP: 0018:ffffc9000f346d38 EFLAGS: 00000202 RAX: 0000000000000002 RBX: ffffffff8fa3d17c RCX: ffffffff8fa3d180 RDX: ffffffff90242820 RSI: ffffffff90242820 RDI: ffffffff8bc08300 RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffffff8df41a20 R10: ffffc9000f346e58 R11: ffffffff81ada120 R12: ffffffff90242824 R13: ffffffff90242825 R14: ffffc9000f346e08 R15: ffffffff81743f85 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] free_unref_folios+0xdb3/0x14f0 mm/page_alloc.c:3000 folios_put_refs+0x584/0x670 mm/swap.c:1002 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x49e/0x1490 mm/shmem.c:1137 shmem_truncate_range mm/shmem.c:1249 [inline] shmem_evict_inode+0x26e/0xa70 mm/shmem.c:1379 evict+0x5f4/0xae0 fs/inode.c:837 __dentry_kill+0x209/0x660 fs/dcache.c:670 finish_dput+0xc9/0x480 fs/dcache.c:879 __fput+0x68e/0xa70 fs/file_table.c:476 task_work_run+0x1d4/0x260 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x6c5/0x2310 kernel/exit.c:971 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112 get_signal+0x1285/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2d0/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcbc198f749 Code: Unable to access opcode bytes at 0x7fcbc198f71f. RSP: 002b:00007fcbbfbf6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: fffffffffffffffc RBX: 00007fcbc1be6090 RCX: 00007fcbc198f749 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000062040200 RBP: 00007fcbc1a13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcbc1be6128 R14: 00007fcbc1be6090 R15: 00007fff7b605ad8