Re: [PATCHv5.1 04/13] x86/mm: Handle LAM on context switch

[Alexander Potapenko]

>         /*
> @@ -491,6 +493,8 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
>  {
>         struct mm_struct *real_prev = this_cpu_read(cpu_tlbstate.loaded_mm);
>         u16 prev_asid = this_cpu_read(cpu_tlbstate.loaded_mm_asid);
> +       unsigned long prev_lam = tlbstate_lam_cr3_mask();
Note: this variable is never used if CONFIG_DEBUG_VM is off.

>  #ifdef CONFIG_DEBUG_VM
> -       if (WARN_ON_ONCE(__read_cr3() != build_cr3(real_prev->pgd, prev_asid))) {
> +       if (WARN_ON_ONCE(__read_cr3() != build_cr3(real_prev->pgd, prev_asid, prev_lam))) {
>                 /*
>                  * If we were to BUG here, we'd be very likely to kill
>                  * the system so hard that we don't see the call trace.