[PATCH 3.17 18/73] dcache: fix kmemcheck warning in switch_names

[Greg Kroah-Hartman]

3.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mikulas Patocka <mpatocka@xxxxxxxxxx>

commit 08d4f7722268755ee34ed1c9e8afee7dfff022bb upstream.

This patch fixes kmemcheck warning in switch_names. The function
switch_names swaps inline names of two dentries. It swaps full arrays
d_iname, no matter how many bytes are really used by the strings. Reading
data beyond string ends results in kmemcheck warning.

We fix the bug by marking both arrays as fully initialized.

Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/dcache.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2407,6 +2407,8 @@ static void switch_names(struct dentry *
 			 */
 			unsigned int i;
 			BUILD_BUG_ON(!IS_ALIGNED(DNAME_INLINE_LEN, sizeof(long)));
+			kmemcheck_mark_initialized(dentry->d_iname, DNAME_INLINE_LEN);
+			kmemcheck_mark_initialized(target->d_iname, DNAME_INLINE_LEN);
 			if (!exchange) {
 				memcpy(dentry->d_iname, target->d_name.name,
 						target->d_name.len + 1);


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