Re: [V3] powerpc/mm/hash64: memset the pagetable pages on allocation.

On Tue, 2018-02-13 at 11:09:33 UTC, "Aneesh Kumar K.V" wrote:

On powerpc we allocate page table pages from slab cache of different sizes. For
now we have a constructor that zero out the objects when we allocate then for
the first time. We expect the objects to be zeroed out when we free the the
object back to slab cache. This happens in the unmap path. For hugetlb pages
we call huge_pte_get_and_clear to do that. With the current configuration of
page table size, both pud and pgd level tables get allocated from the same slab
cache. At the pud level, we use the second half of the table to store the slot
information. But never clear that when unmapping. When such an freed object get
allocated at pgd level, we will have part of the page table page not initlaized
correctly. This result in kernel crash

Simplify this by calling the object initialization after kmem_cache_alloc

Signed-off-by: Aneesh Kumar K.V <redacted>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/fc5c2f4a55a2c258e12013cdf287cf

cheers