+ mm-debug_vm_pgtable-pmd_clear-dont-use-pmd-pud_clear-on-pte-entries.patch added to -mm tree

+ mm-debug_vm_pgtable-pmd_clear-dont-use-pmd-pud_clear-on-pte-entries.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm/debug_vm_pgtable/pmd_clear: don't use pmd/pud_clear on pte entries
has been added to the -mm tree.  Its filename is
     mm-debug_vm_pgtable-pmd_clear-dont-use-pmd-pud_clear-on-pte-entries.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-debug_vm_pgtable-pmd_clear-dont-use-pmd-pud_clear-on-pte-entries.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-debug_vm_pgtable-pmd_clear-dont-use-pmd-pud_clear-on-pte-entries.patch

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------------------------------------------------------
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Subject: mm/debug_vm_pgtable/pmd_clear: don't use pmd/pud_clear on pte entries

pmd_clear() should not be used to clear pmd level pte entries.

Link: https://lkml.kernel.org/r/20200902114222.181353-12-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/debug_vm_pgtable.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/mm/debug_vm_pgtable.c~mm-debug_vm_pgtable-pmd_clear-dont-use-pmd-pud_clear-on-pte-entries
+++ a/mm/debug_vm_pgtable.c
@@ -196,6 +196,8 @@ static void __init pmd_advanced_tests(st
 	pmd = READ_ONCE(*pmdp);
 	WARN_ON(pmd_young(pmd));
 
+	/*  Clear the pte entries  */
+	pmdp_huge_get_and_clear(mm, vaddr, pmdp);
 	pgtable = pgtable_trans_huge_withdraw(mm, pmdp);
 }
 
@@ -319,6 +321,8 @@ static void __init pud_advanced_tests(st
 	pudp_test_and_clear_young(vma, vaddr, pudp);
 	pud = READ_ONCE(*pudp);
 	WARN_ON(pud_young(pud));
+
+	pudp_huge_get_and_clear(mm, vaddr, pudp);
 }
 
 static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot)
@@ -442,8 +446,6 @@ static void __init pud_populate_tests(st
 	 * This entry points to next level page table page.
 	 * Hence this must not qualify as pud_bad().
 	 */
-	pmd_clear(pmdp);
-	pud_clear(pudp);
 	pud_populate(mm, pudp, pmdp);
 	pud = READ_ONCE(*pudp);
 	WARN_ON(pud_bad(pud));
@@ -575,7 +577,6 @@ static void __init pmd_populate_tests(st
 	 * This entry points to next level page table page.
 	 * Hence this must not qualify as pmd_bad().
 	 */
-	pmd_clear(pmdp);
 	pmd_populate(mm, pmdp, pgtable);
 	pmd = READ_ONCE(*pmdp);
 	WARN_ON(pmd_bad(pmd));
_

Patches currently in -mm which might be from aneesh.kumar@linux.ibm.com are

powerpc-mm-add-debug_vm-warn-for-pmd_clear.patch
powerpc-mm-move-setting-pte-specific-flags-to-pfn_pte.patch
mm-debug_vm_pgtable-ppc64-avoid-setting-top-bits-in-radom-value.patch
mm-debug_vm_pgtables-hugevmap-use-the-arch-helper-to-identify-huge-vmap-support.patch
mm-debug_vm_pgtable-savedwrite-enable-savedwrite-test-with-config_numa_balancing.patch
mm-debug_vm_pgtable-thp-mark-the-pte-entry-huge-before-using-set_pmd-pud_at.patch
mm-debug_vm_pgtable-set_pte-pmd-pud-dont-use-set__at-to-update-an-existing-pte-entry.patch
mm-debug_vm_pgtable-locks-move-non-page-table-modifying-test-together.patch
mm-debug_vm_pgtable-locks-take-correct-page-table-lock.patch
mm-debug_vm_pgtable-thp-use-page-table-depost-withdraw-with-thp.patch
mm-debug_vm_pgtable-pmd_clear-dont-use-pmd-pud_clear-on-pte-entries.patch
mm-debug_vm_pgtable-hugetlb-disable-hugetlb-test-on-ppc64.patch
mm-debug_vm_pgtable-avoid-none-pte-in-pte_clear_test.patch