dcache: fix kmemcheck warning in switch_names

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@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/dcache.c b/fs/dcache.c
index 34b40be8af1158d14983af5088ea54f7832776cc..47caaec45df223e402f32a416dcd1f094c731938 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2407,6 +2407,8 @@ static void switch_names(struct dentry *dentry, struct dentry *target,
                         */
                        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);