!26 backport fix use of uninitialized value in LRUHandle

From: @ikernel-mryao 
Reviewed-by: @Charlie_li 
Signed-off-by: @Charlie_li

0007-Fix-use-of-uninitialized-value-in-LRUHandle.patch

@@ -0,0 +1,65 @@
+From 1c75e88055e06da2939f9f4bd294625b76792815 Mon Sep 17 00:00:00 2001
+From: cmumford <cmumford@google.com>
+Date: Mon, 2 Oct 2017 13:57:41 -0700
+Subject: [PATCH] Fix use of uninitialized value in LRUHandle.
+
+If leveldb::Options::block_cache is set to a cache of zero capacity
+then it is possible for LRUHandle::next to be used without having been
+set.
+
+Conditional jump or move depends on uninitialised value(s):
+  leveldb::(anonymous namespace)::LRUHandle::key() const (cache.cc:58)
+  leveldb::(anonymous namespace)::LRUCache::Unref(leveldb::(anonymous namespace)::LRUHandle*) (cache.cc:234)
+  leveldb::(anonymous namespace)::LRUCache::Release(leveldb::Cache::Handle*) (cache.cc:266)
+  leveldb::(anonymous namespace)::ShardedLRUCache::Release(leveldb::Cache::Handle*) (cache.cc:375)
+  leveldb::CacheTest::Insert(int, int, int) (cache_test.cc:59)
+
+This bug forced a commit reversion in Chromium. For more information see
+https://bugs.chromium.org/p/chromium/issues/detail?id=761398#c4
+
+-------------
+Created by MOE: https://github.com/google/moe
+MOE_MIGRATED_REVID=170749054
+---
+ util/cache.cc      | 5 ++++-
+ util/cache_test.cc | 8 ++++++++
+ 2 files changed, 12 insertions(+), 1 deletion(-)
+
+diff --git a/util/cache.cc b/util/cache.cc
+index ce46886..97b82ea 100644
+--- a/util/cache.cc
++++ b/util/cache.cc
+@@ -288,7 +288,10 @@ Cache::Handle* LRUCache::Insert(
+     LRU_Append(&in_use_, e);
+     usage_ += charge;
+     FinishErase(table_.Insert(e));
+-  } // else don't cache.  (Tests use capacity_==0 to turn off caching.)
++  } else {
++    // don't cache.  (It is valid to set capacity_==0 to turn off caching.)
++    e->next = NULL;
++  }
+ 
+   while (usage_ > capacity_ && lru_.next != &lru_) {
+     LRUHandle* old = lru_.next;
+diff --git a/util/cache_test.cc b/util/cache_test.cc
+index 468f7a6..246ab8e 100644
+--- a/util/cache_test.cc
++++ b/util/cache_test.cc
+@@ -219,6 +219,14 @@ TEST(CacheTest, Prune) {
+   ASSERT_EQ(-1, Lookup(2));
+ }
+ 
++TEST(CacheTest, ZeroSizeCache) {
++  delete cache_;
++  cache_ = NewLRUCache(0);
++
++  Insert(1, 100);
++  ASSERT_EQ(-1, Lookup(1));
++}
++
+ }  // namespace leveldb
+ 
+ int main(int argc, char** argv) {
+-- 
+2.40.0.windows.1
+

leveldb.spec

@@ -1,6 +1,6 @@
 Name:           leveldb
 Version:        1.20
-Release:        6
+Release:        7
 Summary:        A key/value database library
 License:        BSD
 URL:            https://github.com/google/leveldb
@@ -12,6 +12,7 @@ Patch0003:      0003-allow-Get-calls-to-avoid-copies-into-std-string.patch
 Patch0004:      0004-bloom_test-failure-on-big-endian-archs.patch
 Patch0005:      0005-broken-db-fix-assertion-in-leveldb-InternalKey-Encod.patch
 Patch0006:      0006-leveldb-Fix-alignment-code-in-SSE4.2-optimized-CRC32.patch
+Patch0007:      0007-Fix-use-of-uninitialized-value-in-LRUHandle.patch
 
 BuildRequires:  make gcc-c++ snappy-devel
 
@@ -73,6 +74,9 @@ make -j1 check
 %{_libdir}/pkgconfig/leveldb.pc
 
 %changelog
+* Fri Jul 7 2023 yaoguangzhong <yaoguangzhong@xfusion.com> -  1.20-7
+- fix use of uninitialized value in LRUHandle
+
 * Tue Apr 25 2023 yaoguangzhong <yaoguangzhong@xfusion.com> -  1.20-6
 - fix alignment code in SSE4.2-optimized CRC32C