Re: [PATCH] mm: Fix pud_alloc_track()

On Thu, 4 Jun 2020 19:48:14 +0300 Mike Rapoport [off-list ref] wrote:

On Thu, Jun 04, 2020 at 09:44:46AM +0200, Joerg Roedel wrote:

quoted

From: Joerg Roedel <redacted>

The pud_alloc_track() needs to do different checks based on whether
__ARCH_HAS_5LEVEL_HACK is defined, like it already does in
pud_alloc(). Otherwise it causes boot failures on PowerPC.

Provide the correct implementations for both possible settings of
__ARCH_HAS_5LEVEL_HACK to fix the boot problems.

There is a patch in mmotm [1] that completely removes
__ARCH_HAS_5LEVEL_HACK which is a part of the series [2] that updates
p4d folding accross architectures. This should fix boot on PowerPC and
the addition of pXd_alloc_track() for __ARCH_HAS_5LEVEL_HACK wouldn't be
necessary.


[1] https://github.com/hnaz/linux-mm/commit/cfae68792af3731ac902ea6ba5ed8df5a0f6bd2f
[2] https://lore.kernel.org/kvmarm/20200414153455.21744-1-rppt@kernel.org/ (local)

That patchset is stacked up behind many other patches, including all
the powerpc stuff in linux-next :(

As it's a big bug fix, I'll pull those patches forward, hopefully send it
all Linuswards later today...