Re: [patch V4 part 1 02/36] x86/hw_breakpoint: Prevent data breakpoints on cpu_entry_area

From: Lai Jiangshan
Date: Sat May 09 2020 - 05:23:43 EST


On Tue, May 5, 2020 at 10:15 PM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> From: Andy Lutomirski <luto@xxxxxxxxxx>
>
> A data breakpoint near the top of an IST stack will cause unresoverable
> recursion. A data breakpoint on the GDT, IDT, or TSS is terrifying.
> Prevent either of these from happening.
>

What happen when a data breakpoint on the direct GDT (load_direct_gdt())
and the debug IDT (load_debug_idt()) which are not considered in this patch?

Thanks
Lai