Re: [PATCH] x86: efi: avoid BUILD_BUG_ON() for non-constant p4d_index

[Nathan Chancellor]

On Fri, Jan 15, 2021 at 07:23:00PM +0100, Borislav Petkov wrote:
> On Thu, Jan 07, 2021 at 11:34:15PM +0100, Arnd Bergmann wrote:
> > From: Arnd Bergmann <arnd@xxxxxxxx>
> > 
> > When 5-level page tables are enabled, clang triggers a BUILD_BUG_ON():
> 
> I have CONFIG_X86_5LEVEL=y, CONFIG_EFI=y and am using Debian clang
> version 10.0.1-8+b1 but my .config builds just fine.
> 
> How do you trigger this?

I triggered it with CONFIG_UBSAN=y + CONFIG_UBSAN_UNSIGNED_OVERFLOW=y
(it can be exposed with an allyesconfig/allmodconfig on mainline
currently).

Cheers,
Nathan