On Thu, Jan 11, 2018 at 12:10 PM, Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> Nice, but why does this not show up in 4.9 and 4.14 and Linus's tree as
> well on this hardware? Nor on the SLES12 SP3 kernel?
>
> What is different there that 4.4 requires? That worries me more than
> your fix (which looks good to me, fwiw.)
I really think it's simply that since v4.6, we've had commit
67a9108ed431 ("x86/efi: Build our own page table structures"), so no
normal EFI use actually uses the old legacy mapping unless you passed
in "efi=old_map" on the kernel command line.
So the bug is there in all versions, it's just that it's normally only
noticeable in 4.4.
But I might be missing some other difference, so take that with a pinch of salt.
Linus