rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7352/2:b..l (detected by 0, t=10502 jiffies, g=21681, q=542) task:syz.4.910 state:R running task stack:27168 pid: 7352 ppid: 4175 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5027 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373 preempt_schedule_notrace+0xf8/0x140 kernel/sched/core.c:6628 preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 rcu_is_watching+0x72/0xa0 kernel/rcu/tree.c:1124 rcu_read_lock include/linux/rcupdate.h:740 [inline] percpu_ref_tryget_many include/linux/percpu-refcount.h:241 [inline] percpu_ref_tryget+0x1e/0x140 include/linux/percpu-refcount.h:266 obj_cgroup_tryget include/linux/memcontrol.h:800 [inline] get_obj_cgroup_from_current+0x21c/0x2f0 mm/memcontrol.c:2927 memcg_slab_pre_alloc_hook mm/slab.h:283 [inline] slab_pre_alloc_hook+0x87/0xc0 mm/slab.h:497 slab_alloc_node mm/slub.c:3134 [inline] kmem_cache_alloc_node+0x49/0x2c0 mm/slub.c:3256 alloc_task_struct_node kernel/fork.c:172 [inline] dup_task_struct+0x57/0xb60 kernel/fork.c:895 copy_process+0x5eb/0x3ef0 kernel/fork.c:2036 kernel_clone+0x210/0x960 kernel/fork.c:2603 __do_sys_clone3 kernel/fork.c:2878 [inline] __se_sys_clone3+0x3e1/0x430 kernel/fork.c:2862 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fdf14d12589 RSP: 002b:00007fffcb4dad58 EFLAGS: 00000206 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00007fdf14c949a0 RCX: 00007fdf14d12589 RDX: 00007fdf14c949a0 RSI: 0000000000000058 RDI: 00007fffcb4dada0 RBP: 00007fdf12b476c0 R08: 00007fdf12b476c0 R09: 00007fffcb4dae87 R10: 0000000000000008 R11: 0000000000000206 R12: ffffffffffffffa8 R13: 000000000000000b R14: 00007fffcb4dada0 R15: 00007fffcb4dae88 rcu: rcu_preempt kthread starved for 9550 jiffies! g21681 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:27064 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5027 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373 schedule+0x11b/0x1f0 kernel/sched/core.c:6456 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.15.177-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3932 [inline] rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619 update_process_times+0x196/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x13b/0x4b0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:22 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline] RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:132 [inline] RIP: 0010:acpi_safe_halt drivers/acpi/processor_idle.c:109 [inline] RIP: 0010:acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:562 Code: b5 37 f7 48 83 e3 08 0f 85 0a 01 00 00 4c 8d 74 24 20 e8 84 2f 3e f7 0f 1f 44 00 00 e8 1a b1 37 f7 0f 00 2d a3 5f bb 00 fb f4 <4c> 89 f3 48 c1 eb 03 42 80 3c 3b 00 74 08 4c 89 f7 e8 db 99 81 f7 RSP: 0018:ffffffff8c807b80 EFLAGS: 000002d3 RAX: ffffffff8a48d476 RBX: 0000000000000000 RCX: ffffffff8c8bd680 RDX: 0000000000000000 RSI: ffffffff8aab2b80 RDI: ffffffff8af9f2c0 RBP: ffffffff8c807c10 R08: ffffffff81870420 R09: fffffbfff1917ad1 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff1900f70 R13: ffff8881423c4804 R14: ffffffff8c807ba0 R15: dffffc0000000000 acpi_idle_enter+0x352/0x4f0 drivers/acpi/processor_idle.c:697 cpuidle_enter_state+0x521/0xef0 drivers/cpuidle/cpuidle.c:237 cpuidle_enter+0x59/0x90 drivers/cpuidle/cpuidle.c:351 call_cpuidle kernel/sched/idle.c:158 [inline] cpuidle_idle_call kernel/sched/idle.c:239 [inline] do_idle+0x3e4/0x670 kernel/sched/idle.c:306 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403 start_kernel+0x48c/0x540 init/main.c:1140 secondary_startup_64_no_verify+0xb1/0xbb