Patch "powerpc/hugetlb: Call mm_dec_nr_pmds() in hugetlb_free_pmd_range()" has been added to the 4.0-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    powerpc/hugetlb: Call mm_dec_nr_pmds() in hugetlb_free_pmd_range()

to the 4.0-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     powerpc-hugetlb-call-mm_dec_nr_pmds-in-hugetlb_free_pmd_range.patch
and it can be found in the queue-4.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 50c6a665b383cb5839e45d04e36faeeefaffa052 Mon Sep 17 00:00:00 2001
From: Scott Wood <scottwood@freescale.com>
Date: Fri, 10 Apr 2015 19:37:34 -0500
Subject: powerpc/hugetlb: Call mm_dec_nr_pmds() in hugetlb_free_pmd_range()

From: Scott Wood <scottwood@freescale.com>

commit 50c6a665b383cb5839e45d04e36faeeefaffa052 upstream.

Commit dc6c9a35b66b5 ("mm: account pmd page tables to the process")
added a counter that is incremented whenever a PMD is allocated and
decremented whenever a PMD is freed.  For hugepages on PPC, common code
is used to allocated PMDs, but arch-specific code is used to free PMDs.

This results in kernel output such as "BUG: non-zero nr_pmds on freeing
mm: 1" when using hugepages.

Update the PPC hugepage PMD freeing code to decrement the count, just
as the above commit did for free_pmd_range().

Fixes: dc6c9a35b66b5 ("mm: account pmd page tables to the process")
Signed-off-by: Scott Wood <scottwood@freescale.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/powerpc/mm/hugetlbpage.c |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -581,6 +581,7 @@ static void hugetlb_free_pmd_range(struc
 	pmd = pmd_offset(pud, start);
 	pud_clear(pud);
 	pmd_free_tlb(tlb, pmd, start);
+	mm_dec_nr_pmds(tlb->mm);
 }
 
 static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,


Patches currently in stable-queue which might be from scottwood@freescale.com are

queue-4.0/powerpc-hugetlb-call-mm_dec_nr_pmds-in-hugetlb_free_pmd_range.patch