[PATCH 4.19 174/190] mm/migrate.c: initialize pud_entry in migrate_vma()

[Greg Kroah-Hartman]

[ Upstream commit 7b358c6f12dc82364f6d317f8c8f1d794adbc3f5 ]

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.

Link: http://lkml.kernel.org/r/20190719233225.12243-1-rcampbell@xxxxxxxxxx
Fixes: 8763cb45ab967 ("mm/migrate: new memory migration helper for use with device memory")
Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx>
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: "JÃrÃme Glisse" <jglisse@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 mm/migrate.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index b2ea7d1e6f248..0c48191a90368 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2328,16 +2328,13 @@ next:
  */
 static void migrate_vma_collect(struct migrate_vma *migrate)
 {
-	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_invalidate_range_start(mm_walk.mm,
 					    migrate->start,
-- 
2.20.1