sched: DL replenish lagged too much rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=0624/1/0x4000000000000000 softirq=144005/144006 fqs=2 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P23571/1:b..l rcu: (detected by 1, t=10502 jiffies, g=121081, q=300 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 7842 Comm: kworker/u8:16 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: netns cleanup_net RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:222 [inline] RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:233 [inline] RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline] RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:646 [inline] RIP: 0010:cpu_online include/linux/cpumask.h:1205 [inline] RIP: 0010:trace_hrtimer_cancel include/trace/events/timer.h:317 [inline] RIP: 0010:debug_deactivate+0x5c/0x200 kernel/time/hrtimer.c:484 Code: 00 89 de e8 46 df 11 00 83 fb 07 77 6d e8 fc da 11 00 41 89 de c1 eb 06 48 8d 3c dd 70 96 c3 8f be 08 00 00 00 e8 84 79 76 00 <31> f6 4c 0f a3 35 2a 98 15 0e 0f 92 c3 40 0f 92 c6 bf 02 00 00 00 RSP: 0018:ffffc90000007d18 EFLAGS: 00000056 RAX: ffffffff81adfe01 RBX: 0000000000000000 RCX: ffffffff81adfe3c RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8fc39670 RBP: ffffc90000007e90 R08: ffffffff8fc39677 R09: 1ffffffff1f872ce R10: dffffc0000000000 R11: fffffbfff1f872cf R12: ffff8880273b9340 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8627bc0 FS: 0000000000000000(0000) GS:ffff8881259e7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbe6c0a8d58 CR3: 000000004fbee000 CR4: 00000000003526f0 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1745 [inline] __hrtimer_run_queues+0x2b0/0xc60 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1058 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x18d/0x360 kernel/locking/lockdep.c:5872 Code: 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 4b 16 26 11 48 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e 41 5f <5d> c3 cc cc cc cc cc 65 8b 05 75 56 26 11 85 c0 75 ce 65 8b 05 2a RSP: 0018:ffffc9001db9f000 EFLAGS: 00000286 RAX: 221608b6e1cb5400 RBX: ffffffff8173e5c8 RCX: 221608b6e1cb5400 RDX: 0000000000000000 RSI: ffffffff8dd9240a RDI: ffffffff8c03aa60 RBP: ffffffff8173bd25 R08: 0000000000000000 R09: ffffffff8173bd25 R10: ffffc9001db9f148 R11: fffff52003b73e35 R12: 1ffff92003b73e29 R13: ffffc9001db9f180 R14: ffffc9001db9f148 R15: ffffffff8173bd25 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1169 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:758 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:559 __call_rcu_common kernel/rcu/tree.c:3123 [inline] call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3243 kernfs_put+0x19e/0x480 fs/kernfs/dir.c:591 kernfs_remove_by_name_ns+0xb7/0x130 fs/kernfs/dir.c:1718 kernfs_remove_by_name include/linux/kernfs.h:633 [inline] remove_files fs/sysfs/group.c:28 [inline] sysfs_remove_group+0xfc/0x2c0 fs/sysfs/group.c:322 sysfs_remove_groups+0x54/0xb0 fs/sysfs/group.c:346 __kobject_del+0x84/0x300 lib/kobject.c:595 kobject_del+0x45/0x60 lib/kobject.c:627 destroy_port drivers/infiniband/core/sysfs.c:1279 [inline] ib_free_port_attrs+0x289/0x3b0 drivers/infiniband/core/sysfs.c:1408 remove_one_compat_dev drivers/infiniband/core/device.c:1038 [inline] rdma_dev_exit_net+0x1d8/0x340 drivers/infiniband/core/device.c:1176 ops_exit_list net/core/net_namespace.c:199 [inline] ops_undo_list+0x49a/0x990 net/core/net_namespace.c:252 cleanup_net+0x4d8/0x810 net/core/net_namespace.c:701 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:syz.2.4522 state:R running task stack:24296 pid:23571 tgid:23569 ppid:19369 task_flags:0x10400140 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7291 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:unwind_next_frame+0x1721/0x2390 arch/x86/kernel/unwind_orc.c:648 Code: 18 02 00 00 80 3d 9e 0d 56 11 00 0f 85 0b 02 00 00 c6 05 91 0d 56 11 01 4c 89 f7 e8 89 0c 00 00 e9 f7 01 00 00 48 8b 54 24 08 <48> 8d 5a 02 48 83 c2 03 48 89 d8 48 c1 e8 03 0f b6 04 28 84 c0 0f RSP: 0018:ffffc9000bb3e8b8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffc9000bb3e9c0 RCX: 0000000000000000 RDX: ffffffff908b8e32 RSI: 0000000000000001 RDI: ffffc9000bb3e9e8 RBP: dffffc0000000000 R08: ffffc9000bb3e9e7 R09: 0000000000000000 R10: ffffc9000bb3e9d8 R11: fffff52001767d3d R12: ffffc9000bb3fb60 R13: ffffc9000bb3e9d8 R14: ffffc9000bb3e988 R15: 1ffffffff21171c6 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:156 __set_page_owner+0x8d/0x4a0 mm/page_owner.c:329 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3869 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5159 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2435 shmem_alloc_folio mm/shmem.c:1884 [inline] shmem_alloc_and_add_folio+0x4ba/0x10f0 mm/shmem.c:1923 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2546 shmem_fault+0x179/0x390 mm/shmem.c:2747 __do_fault+0x138/0x390 mm/memory.c:5324 do_shared_fault mm/memory.c:5811 [inline] do_fault mm/memory.c:5885 [inline] do_pte_missing mm/memory.c:4405 [inline] handle_pte_fault mm/memory.c:6226 [inline] __handle_mm_fault+0x1847/0x5400 mm/memory.c:6367 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6536 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0x165c/0x2a00 mm/gup.c:1428 __get_user_pages_locked mm/gup.c:1692 [inline] __gup_longterm_locked+0x7f6/0x1660 mm/gup.c:2481 gup_fast_fallback+0x1d65/0x22d0 mm/gup.c:3220 io_pin_pages+0xba/0x1b0 io_uring/memmap.c:63 io_region_pin_pages+0x7d/0x190 io_uring/memmap.c:142 io_create_region+0x386/0x480 io_uring/memmap.c:222 io_allocate_scq_urings+0x54b/0x870 io_uring/io_uring.c:3644 io_uring_create+0x591/0xba0 io_uring/io_uring.c:3858 io_uring_setup io_uring/io_uring.c:3936 [inline] __do_sys_io_uring_setup io_uring/io_uring.c:3970 [inline] __se_sys_io_uring_setup+0x264/0x270 io_uring/io_uring.c:3961 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7db358ec29 RSP: 002b:00007f7db43c7fc8 EFLAGS: 00000202 ORIG_RAX: 00000000000001a9 RAX: ffffffffffffffda RBX: 00007f7db37d6090 RCX: 00007f7db358ec29 RDX: 0000000000000000 RSI: 0000200000000400 RDI: 0000000000002c0e RBP: 0000200000000400 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000002c0e R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10498 jiffies! g121081 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:27080 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 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+0x4bc/0x870 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: 1 UID: 0 PID: 21181 Comm: kworker/u8:30 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xd33/0x12d0 kernel/smp.c:877 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 36 79 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 e1 74 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 c5 74 RSP: 0018:ffffc9000bb8f640 EFLAGS: 00000293 RAX: ffffffff81b4645b RBX: 1ffff110170c8441 RCX: ffff8880560a1e40 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000bb8f7c0 R08: ffffffff8fc39677 R09: 1ffffffff1f872ce R10: dffffc0000000000 R11: fffffbfff1f872cf R12: ffff8880b8642208 R13: dffffc0000000000 R14: ffff8880b873b200 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125ae7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3df414 CR3: 000000000e138000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2713 [inline] smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2923 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:852 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245