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 71acf8d6f2be8bcfaa0d32c8de61d01f135e4135..03dca3cad9188e9a626f9ff00149317fc7032c5f 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2393,6 +2393,8 @@ static void swap_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);
                        for (i = 0; i < DNAME_INLINE_LEN / sizeof(long); i++) {
                                swap(((long *) &dentry->d_iname)[i],
                                     ((long *) &target->d_iname)[i]);