Re: [GIT PULL] x86/uapi for 3.8

[Linus Torvalds]

On Mon, Dec 17, 2012 at 1:04 AM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>
> How about this being caused by using the same lower level
> page table entries that swapper_pg_dir uses, namely including
> the _PAGE_GLOBAL bits? efi_call_virt_{pre,epi}log() only write
> CR3 (see 185034e72d591f9465e5e18f937ed642e7ea0070), but
> would need to also flip CR4.PGE afaict.

Now *this* is the kind of issue that I could easily see causing major
corruption, but be subtle enough to not happen reliably. Coming back
from the EFI calls (or going into them) with stale TLB contents due to
global pages could explain things.

Good thinking. That efi call code should use flush_tlb_kernel() (or
__flush_tlb_global() if it wants to avoid any paravirtualization
stuff) if it has global pages in different places from the normal
kernel map. Does it really have that?

            Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/