crypto: don't track xor test pages with kmemcheck

The xor tests are run on uninitialized data, because it is doesn't
really matter what the underlying data is. Annotate this false-
positive warning.

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/crypto/xor.c b/crypto/xor.c
index 996b6ee57d9e..fc5b836f3430 100644
--- a/crypto/xor.c
+++ b/crypto/xor.c
@@ -101,7 +101,12 @@ calibrate_xor_blocks(void)
         void *b1, *b2;
         struct xor_block_template *f, *fastest;
 
-        b1 = (void *) __get_free_pages(GFP_KERNEL, 2);
+        /*
+         * Note: Since the memory is not actually used for _anything_ but to
+         * test the XOR speed, we don't really want kmemcheck to warn about
+         * reading uninitialized bytes here.
+         */
+        b1 = (void *) __get_free_pages(GFP_KERNEL | __GFP_NOTRACK, 2);
         if (!b1) {
                 printk(KERN_WARNING "xor: Yikes!  No memory available.\n");
                 return -ENOMEM;