Re: [RFC PATCH v3 04/10] sched/core: Dont allow to use CPU marked as paravirt

[Shrikanth Hegde]

On 9/11/25 10:46 AM, K Prateek Nayak wrote:

Hello Shrikanth,

Hi Prateek, Thanks for looking into this.

On 9/10/2025 11:12 PM, Shrikanth Hegde wrote:

@@ -2462,8 +2462,13 @@ static inline bool is_cpu_allowed(struct task_struct *p, 
int cpu)
                return cpu_online(cpu);

/* Non kernel threads are not allowed during either online or offline. */

-       if (!(p->flags & PF_KTHREAD))
-               return cpu_active(cpu);
+       if (!(p->flags & PF_KTHREAD)) {
+               /* A user thread shouldn't be allowed on a paravirt cpu */
+               if (is_cpu_paravirt(cpu))
+                       return false;
+               else

nit. redundant "else". I think this can be simplified as:

alright.

     return !is_cpu_paravirt(cpu) && cpu_active(cpu);

+                       return cpu_active(cpu);
+       }