verity: fix valgrind warnings in OddLeafCount

dm-bht.c

  /*
  * Copyright (C) 2010 The Chromium OS Authors <chromium-os-dev@chromium.org>
  *
  * Device-Mapper block hash tree interface.
  * See Documentation/device-mapper/dm-bht.txt for details.
  *
  * This file is released under the GPL.
  */
 
 #include <asm/atomic.h>
@@ skipping 749 matching lines @@
          *     The number of updated entries is NOT tracked.
          */
         if (state == DM_BHT_ENTRY_UNALLOCATED) {
                 node_page = (struct page *) mempool_alloc(bht->entry_pool,
                                                           GFP_KERNEL);
                 if (!node_page) {
                         atomic_set(&entry->state, DM_BHT_ENTRY_ERROR);
                         return -ENOMEM;
                 }
                 entry->nodes = page_address(node_page);
+                memset(entry->nodes, 0, PAGE_SIZE);
                 /* TODO(wad) could expose this to the caller to that they
                  * can transition from unallocated to ready manually.
                  */
                 atomic_set(&entry->state, DM_BHT_ENTRY_READY);
         } else if (state <= DM_BHT_ENTRY_ERROR) {
                 DMCRIT("leaf entry for block %u is invalid",
                       block_index);
                 return state;
         } else if (state == DM_BHT_ENTRY_PENDING) {
                 DMERR("leaf data is pending for block %u", block_index);
@@ skipping 411 matching lines @@
                 DMERR("no root digest exists to export");
                 if (available > 0)
                         *hexdigest = 0;
                 return -1;
         }
         dm_bht_bin_to_hex(bht->root_digest, hexdigest, bht->digest_size);
         return 0;
 }
 EXPORT_SYMBOL(dm_bht_root_hexdigest);