Re: [PATCH 6.6.y] Revert "x86/mm/ident_map: Use gbpages only where full GB page should be mapped."

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Apr 02, 2024 at 12:29:09PM -0500, Steve Wahl wrote:
> From: Ingo Molnar <mingo@kernel.org>
> 
> This reverts commit d794734c9bbfe22f86686dc2909c25f5ffe1a572.
> 
> While the original change tries to fix a bug, it also unintentionally broke
> existing systems, see the regressions reported at:
> 
>   https://lore.kernel.org/all/3a1b9909-45ac-4f97-ad68-d16ef1ce99db@pavinjoseph.com/
> 
> Since d794734c9bbf was also marked for -stable, let's back it out before
> causing more damage.
> 
> Note that due to another upstream change the revert was not 100% automatic:
> 
>   0a845e0f6348 mm/treewide: replace pud_large() with pud_leaf()
> 
> Signed-off-by: Ingo Molnar <mingo@kernel.org>
> Cc: <stable@vger.kernel.org>
> Cc: Russ Anderson <rja@hpe.com>
> Cc: Steve Wahl <steve.wahl@hpe.com>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Link: https://lore.kernel.org/all/3a1b9909-45ac-4f97-ad68-d16ef1ce99db@pavinjoseph.com/
> Fixes: d794734c9bbf ("x86/mm/ident_map: Use gbpages only where full GB page should be mapped.")
> (cherry picked from commit c567f2948f57bdc03ed03403ae0234085f376b7d)
> Signed-off-by: Steve Wahl <steve.wahl@hpe.com>
> ---
> 
> Thought I'd try and be of help.  The pud_large() / pud_leaf() change
> is what caused the difficulty in reversion.

Thanks, Sasha already did this one, I'll go queue the other backports up
now though.

greg k-h