Memory leak reported by ASAN

[zouyonghao]

=================================================================
==91926==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 72 byte(s) in 1 object(s) allocated from:
    #0 0x626a8d in operator new(unsigned long) (/home/zyh/braft/example/atomic/atomic_server+0x626a8d)
    #1 0x658f95 in braft::FileBasedSingleMetaStorage::new_instance(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) const /home/zyh/braft/src/braft/raft_meta.cpp:555:12
    #2 0x69bceb in braft::RaftMetaStorage::create(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) /home/zyh/braft/src/braft/storage.cpp:134:18
    #3 0x73c479 in braft::NodeImpl::init_meta_storage() /home/zyh/braft/src/braft/node.cpp:287:21
    #4 0x7411bc in braft::NodeImpl::init(braft::NodeOptions const&) /home/zyh/braft/src/braft/node.cpp:514:9
    #5 0x62b87f in example::Atomic::start() (/home/zyh/braft/example/atomic/atomic_server+0x62b87f)
    #6 0x62995f in main (/home/zyh/braft/example/atomic/atomic_server+0x62995f)
    #7 0x7f7893552bf6 in __libc_start_main /build/glibc-S9d2JN/glibc-2.27/csu/../csu/libc-start.c:310

Direct leak of 56 byte(s) in 1 object(s) allocated from:
    #0 0x626a8d in operator new(unsigned long) (/home/zyh/braft/example/atomic/atomic_server+0x626a8d)
    #1 0xb5eff4 in brpc::Server::StartInternal(in_addr const&, brpc::PortRange const&, brpc::ServerOptions const*) /home/zyh/incubator-brpc/src/brpc/server.cpp:783:22
    #2 0xb67672 in brpc::Server::Start(butil::EndPoint const&, brpc::ServerOptions const*) /home/zyh/incubator-brpc/src/brpc/server.cpp:1062:12
    #3 0xb67672 in brpc::Server::Start(int, brpc::ServerOptions const*) /home/zyh/incubator-brpc/src/brpc/server.cpp:1081:12
    #4 0x6298d5 in main (/home/zyh/braft/example/atomic/atomic_server+0x6298d5)
    #5 0x7f7893552bf6 in __libc_start_main /build/glibc-S9d2JN/glibc-2.27/csu/../csu/libc-start.c:310

Indirect leak of 18 byte(s) in 1 object(s) allocated from:
    #0 0x626a8d in operator new(unsigned long) (/home/zyh/braft/example/atomic/atomic_server+0x626a8d)
    #1 0x659083 in void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*, std::forward_iterator_tag) /usr/bin/../lib/gcc/x86_64-linux-gnu/7.5.0/../../../../include/c++/7.5.0/bits/basic_string.tcc:219:14
    #2 0x659083 in void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct_aux<char*>(char*, char*, std::__false_type) /usr/bin/../lib/gcc/x86_64-linux-gnu/7.5.0/../../../../include/c++/7.5.0/bits/basic_string.h:236:11
    #3 0x659083 in void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*) /usr/bin/../lib/gcc/x86_64-linux-gnu/7.5.0/../../../../include/c++/7.5.0/bits/basic_string.h:255:4
    #4 0x659083 in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) /usr/bin/../lib/gcc/x86_64-linux-gnu/7.5.0/../../../../include/c++/7.5.0/bits/basic_string.h:440:9
    #5 0x659083 in braft::FileBasedSingleMetaStorage::FileBasedSingleMetaStorage(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) /home/zyh/braft/src/braft/raft_meta.h:74:30
    #6 0x659083 in braft::FileBasedSingleMetaStorage::new_instance(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) const /home/zyh/braft/src/braft/raft_meta.cpp:555:16
    #7 0x69bceb in braft::RaftMetaStorage::create(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) /home/zyh/braft/src/braft/storage.cpp:134:18
    #8 0x73c479 in braft::NodeImpl::init_meta_storage() /home/zyh/braft/src/braft/node.cpp:287:21
    #9 0x7411bc in braft::NodeImpl::init(braft::NodeOptions const&) /home/zyh/braft/src/braft/node.cpp:514:9
    #10 0x62b87f in example::Atomic::start() (/home/zyh/braft/example/atomic/atomic_server+0x62b87f)
    #11 0x62995f in main (/home/zyh/braft/example/atomic/atomic_server+0x62995f)
    #12 0x7f7893552bf6 in __libc_start_main /build/glibc-S9d2JN/glibc-2.27/csu/../csu/libc-start.c:310

SUMMARY: AddressSanitizer: 146 byte(s) leaked in 3 allocation(s).

看起来 FileBasedSingleMetaStorage 这个对象 leak 了

@PFZheng @Edward-xk @ipconfigme

[lday0321]

gdb跟了下，在v1.1.2版本中，发现是在NodeImpl::init阶段，两次执行了init_meta_storage，由于第二次init_meta_storage中的_meta_storage是直接赋值，没有删除第一次init_meta_storage时，new出来的_meta_storage，导致第一次RaftMetaStorage::create(_options.raft_meta_uri);没有释放，已经在该PR中修复， master分支已经OK

[zouyonghao]

感谢分享 @lday0321

[zouyonghao]

Based on our discussion, may I request a CVE for this issue? It'll help end-users know that they should update and benefit our research.
@lday0321 @PFZheng