mm/debug_vm_pgtable/locks: take correct page table lock

Make sure we call pte accessors with correct lock held.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lkml.kernel.org/r/20200902114222.181353-10-aneesh.kumar@linux.ibm.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/debug_vm_pgtable.c

@@ -1033,30 +1033,39 @@ static int __init debug_vm_pgtable(void)
 
 	hugetlb_basic_tests(pte_aligned, prot);
 
-	pte_clear_tests(mm, ptep, vaddr);
-	pmd_clear_tests(mm, pmdp);
-	pud_clear_tests(mm, pudp);
-	p4d_clear_tests(mm, p4dp);
-	pgd_clear_tests(mm, pgdp);
+	/*
+	 * Page table modifying tests. They need to hold
+	 * proper page table lock.
+	 */
 
 	ptl = pte_lockptr(mm, pmdp);
 	spin_lock(ptl);
-
+	pte_clear_tests(mm, ptep, vaddr);
 	pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
-	pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot);
-	pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot);
-	hugetlb_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
-
+	pte_unmap_unlock(ptep, ptl);
 
+	ptl = pmd_lock(mm, pmdp);
+	pmd_clear_tests(mm, pmdp);
+	pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot);
 	pmd_huge_tests(pmdp, pmd_aligned, prot);
+	pmd_populate_tests(mm, pmdp, saved_ptep);
+	spin_unlock(ptl);
+
+	ptl = pud_lock(mm, pudp);
+	pud_clear_tests(mm, pudp);
+	pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot);
 	pud_huge_tests(pudp, pud_aligned, prot);
+	pud_populate_tests(mm, pudp, saved_pmdp);
+	spin_unlock(ptl);
 
-	pte_unmap_unlock(ptep, ptl);
+	hugetlb_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
 
-	pmd_populate_tests(mm, pmdp, saved_ptep);
-	pud_populate_tests(mm, pudp, saved_pmdp);
+	spin_lock(&mm->page_table_lock);
+	p4d_clear_tests(mm, p4dp);
+	pgd_clear_tests(mm, pgdp);
 	p4d_populate_tests(mm, p4dp, saved_pudp);
 	pgd_populate_tests(mm, pgdp, saved_p4dp);
+	spin_unlock(&mm->page_table_lock);
 
 	p4d_free(mm, saved_p4dp);
 	pud_free(mm, saved_pudp);