[PATCH] mm/migrate: initialize pud_entry in migrate_vma()

From: Ralph Campbell <rcampbell@nvidia.com>
To: <linux-mm@kvack.org>
Cc: linux-kernel@vger.kernel.org,
	"Ralph Campbell" <rcampbell@nvidia.com>,
	stable@vger.kernel.org, "Jérôme Glisse" <jglisse@redhat.com>,
	"Andrew Morton" <akpm@linux-foundation.org>
Subject: [PATCH] mm/migrate: initialize pud_entry in migrate_vma()
Date: Fri, 19 Jul 2019 16:32:25 -0700	[thread overview]
Message-ID: <20190719233225.12243-1-rcampbell@nvidia.com> (raw)

When CONFIG_MIGRATE_VMA_HELPER is enabled, migrate_vma() calls
migrate_vma_collect() which initializes a struct mm_walk but
didn't initialize mm_walk.pud_entry. (Found by code inspection)
Use a C structure initialization to make sure it is set to NULL.

Fixes: 8763cb45ab967 ("mm/migrate: new memory migration helper for use with
device memory")
Cc: stable@vger.kernel.org
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 mm/migrate.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index 515718392b24..a42858d8e00b 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2340,16 +2340,13 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 static void migrate_vma_collect(struct migrate_vma *migrate)
 {
 	struct mmu_notifier_range range;
-	struct mm_walk mm_walk;
-
-	mm_walk.pmd_entry = migrate_vma_collect_pmd;
-	mm_walk.pte_entry = NULL;
-	mm_walk.pte_hole = migrate_vma_collect_hole;
-	mm_walk.hugetlb_entry = NULL;
-	mm_walk.test_walk = NULL;
-	mm_walk.vma = migrate->vma;
-	mm_walk.mm = migrate->vma->vm_mm;
-	mm_walk.private = migrate;
+	struct mm_walk mm_walk = {
+		.pmd_entry = migrate_vma_collect_pmd,
+		.pte_hole = migrate_vma_collect_hole,
+		.vma = migrate->vma,
+		.mm = migrate->vma->vm_mm,
+		.private = migrate,
+	};
 
 	mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm_walk.mm,
 				migrate->start,
-- 
2.20.1

