From b11a8b1b9a63bf80d48ce91230115fc721361133 Mon Sep 17 00:00:00 2001
From: Yanqin Jin <yanqin@fb.com>
Date: Thu, 14 May 2020 18:48:06 -0700
Subject: [PATCH] Fix valgrind error by init memory region (#6842)

Summary:
As title. After allocating a memory buffer, initialize its content to 0s.
This fixes valgrind issue introduced in https://github.com/facebook/rocksdb/issues/6709.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6842

Test Plan:
```
$make valgrind_test
$valgrind --tool=memcheck --track-origins=yes ./db_test2 --gtest_filter=DBTest2.CompressionFailures
```

Reviewed By: pdillinger

Differential Revision: D21551848

Pulled By: riversand963

fbshipit-source-id: e87a6f413e3f3d92d8e23d8ecc4cf93479c6674c
---
 db/db_test2.cc | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/db/db_test2.cc b/db/db_test2.cc
index 59e264ef4..26da04417 100644
--- a/db/db_test2.cc
+++ b/db/db_test2.cc
@@ -1317,10 +1317,9 @@ TEST_F(DBTest2, CompressionFailures) {
         if (curr_compression_failure_type == kTestDecompressionCorruption) {
           BlockContents* contents = static_cast<BlockContents*>(arg);
           // Ensure uncompressed data != original data
-          std::unique_ptr<char[]> fake_data(
-              new char[contents->data.size() + 1]);
-          *contents =
-              BlockContents(std::move(fake_data), contents->data.size() + 1);
+          const size_t len = contents->data.size() + 1;
+          std::unique_ptr<char[]> fake_data(new char[len]());
+          *contents = BlockContents(std::move(fake_data), len);
         }
       });