sched: DL replenish lagged too much rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=4fd4/1/0x4000000000000000 softirq=51941/51941 fqs=2 rcu: (detected by 0, t=10502 jiffies, g=45093, q=340 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5193 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:cpu_max_bits_warn include/linux/cpumask.h:135 [inline] RIP: 0010:cpumask_check include/linux/cpumask.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_start include/trace/events/timer.h:222 [inline] RIP: 0010:debug_activate kernel/time/hrtimer.c:478 [inline] RIP: 0010:enqueue_hrtimer+0x42/0x3a0 kernel/time/hrtimer.c:1081 Code: 00 fc ff df e8 5f 2e 12 00 48 89 df 48 c7 c6 20 09 6d 8b e8 e0 f5 e4 02 0f 1f 44 00 00 e8 46 2e 12 00 65 44 8b 3d 02 4a c0 10 07 00 00 00 44 89 fe e8 71 32 12 00 41 83 ff 07 0f 87 5c 01 00 RSP: 0018:ffffc90000a08d08 EFLAGS: 00000006 RAX: ffffffff81add62a RBX: ffff88807ddcd340 RCX: ffff88807d6d0000 RDX: 0000000000010000 RSI: 0000000000000004 RDI: 00000000ffffffff RBP: 0000000000000000 R08: ffffffff99a56acb R09: 1ffffffff334ad59 R10: dffffc0000000000 R11: fffffbfff334ad5a R12: dffffc0000000000 R13: dffffc0000000000 R14: ffff8880b8927bc0 R15: 0000000000000001 FS: 00007ffbd0fb3880(0000) GS:ffff88812623e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f17391d9f98 CR3: 000000002176f000 CR4: 0000000000350ef0 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1794 [inline] __hrtimer_run_queues+0x656/0xc60 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:seqcount_lockdep_reader_access+0x17d/0x1c0 include/linux/seqlock.h:75 Code: ff 4d 85 ed 75 16 e8 02 ef 84 ff eb 15 e8 fb ee 84 ff e8 96 fc 0a 09 4d 85 ed 74 ea e8 ec ee 84 ff fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 27 00 00 00 00 66 43 c7 44 27 09 00 00 43 c6 44 27 0b 00 RSP: 0018:ffffc9000394f700 EFLAGS: 00000293 RAX: ffffffff823b1584 RBX: 0000000000000000 RCX: ffff88807d6d0000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000394f7b0 R08: ffffffff8f7cd477 R09: 1ffffffff1ef9a8e R10: dffffc0000000000 R11: fffffbfff1ef9a8f R12: dffffc0000000000 R13: 0000000000000200 R14: ffffffff823b2433 R15: 1ffff92000729ee0 __follow_mount_rcu fs/namei.c:1610 [inline] handle_mounts fs/namei.c:1635 [inline] step_into+0x653/0xe80 fs/namei.c:1989 walk_component fs/namei.c:2157 [inline] link_path_walk+0x77b/0xea0 fs/namei.c:2519 path_lookupat+0x97/0x430 fs/namei.c:2675 filename_lookup+0x212/0x570 fs/namei.c:2705 vfs_statx+0xf8/0x550 fs/stat.c:353 vfs_fstatat+0x118/0x170 fs/stat.c:375 __do_sys_newfstatat fs/stat.c:542 [inline] __se_sys_newfstatat fs/stat.c:536 [inline] __x64_sys_newfstatat+0x116/0x190 fs/stat.c:536 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: 0033:0x7ffbd0911b0a Code: 48 8b 15 f1 f2 0d 00 f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 89 ca b8 06 01 00 00 0f 05 <3d> 00 f0 ff ff 77 07 31 c0 c3 0f 1f 40 00 48 8b 15 b9 f2 0d 00 f7 RSP: 002b:00007ffeabc97c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 00007ffeabc98100 RCX: 00007ffbd0911b0a RDX: 00007ffeabc97c70 RSI: 00007ffeabc98100 RDI: 00000000ffffff9c RBP: 00005588171bb910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffeabc97d00 R13: 00005587fb219100 R14: 0000000000000001 R15: 00007ffeabc99600 rcu: rcu_preempt kthread starved for 10490 jiffies! g45093 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:27088 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 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: 0 UID: 0 PID: 4515 Comm: kworker/u8:8 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xd38/0x12d0 kernel/smp.c:877 Code: 89 ee 83 e6 01 31 ff e8 b6 73 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 61 6f 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 45 6f 0b 00 eb e4 44 RSP: 0018:ffffc9000d9f7640 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff11017127ffd RCX: ffff888032471e40 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000d9f77c0 R08: ffffffff8f7cd477 R09: 1ffffffff1ef9a8e R10: dffffc0000000000 R11: fffffbfff1ef9a8f R12: ffff8880b893ffe8 R13: dffffc0000000000 R14: ffff8880b883b240 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88812613e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8987db55d8 CR3: 000000000dd38000 CR4: 0000000000350ef0 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