Mismatched free()/delete in MsgPack

Question

I try to use Msgpack in my program. Can someone help me with next example (Streaming feature) from msgpack wiki: http://wiki.msgpack.org/pages/viewpage.action?pageId=1081387 and provide more correct example of using this library with streaming feature.

#include <msgpack.hpp> 
#include <iostream> 
#include <string> 

int main(void) { 
    // serializes multiple objects using msgpack::packer. 
    msgpack::sbuffer buffer; 

    msgpack::packer<msgpack::sbuffer> pk(&buffer); 
    pk.pack(std::string("Log message ... 1")); 
    pk.pack(std::string("Log message ... 2")); 
    pk.pack(std::string("Log message ... 3")); 

    // deserializes these objects using msgpack::unpacker. 
    msgpack::unpacker pac; 

    // feeds the buffer. 
    pac.reserve_buffer(buffer.size()); 
    memcpy(pac.buffer(), buffer.data(), buffer.size()); 
    pac.buffer_consumed(buffer.size()); 

    // now starts streaming deserialization. 
    msgpack::unpacked result; 
    while(pac.next(&result)) { 
        std::cout << result.get() << std::endl; 
    } 

    // results: 
    // $ g++ stream.cc -lmsgpack -o stream 
    // $ ./stream 
    // "Log message ... 1" 
    // "Log message ... 2" 
    // "Log message ... 3" 
}

Valgrind say that it has next errors:

==11325== 1 errors in context 1 of 2:
==11325== Mismatched free() / delete / delete []
==11325==    at 0x48CC919: operator delete(void*) (vg_replace_malloc.c:387)
==11325==    by 0x804A623: std::auto_ptr<msgpack::zone>::reset(msgpack::zone*) (auto_ptr.h:242)
==11325==    by 0x804A2E1: msgpack::unpacker::next(msgpack::unpacked*) (unpack.hpp:229)
==11325==    by 0x8049E93: main (pack2.cpp:24)
==11325==  Address 0x6e447c0 is 0 bytes inside a block of size 8,220 alloc'd
==11325==    at 0x48CD876: malloc (vg_replace_malloc.c:236)
==11325==    by 0x48DABC9: msgpack_zone_new (zone.c:198)
==11325==    by 0x48D811F: msgpack_unpacker_release_zone (unpack.c:333)
==11325==    by 0x804A3DA: msgpack::unpacker::release_zone() (unpack.hpp:261)
==11325==    by 0x804A31C: msgpack::unpacker::next(msgpack::unpacked*) (unpack.hpp:234)
==11325==    by 0x8049E93: main (pack2.cpp:24)
==11325== 
==11325== 
==11325== 2 errors in context 2 of 2:
==11325== Mismatched free() / delete / delete []
==11325==    at 0x48CC919: operator delete(void*) (vg_replace_malloc.c:387)
==11325==    by 0x804A623: std::auto_ptr<msgpack::zone>::reset(msgpack::zone*) (auto_ptr.h:242)
==11325==    by 0x804A335: msgpack::unpacker::next(msgpack::unpacked*) (unpack.hpp:234)
==11325==    by 0x8049E93: main (pack2.cpp:24)
==11325==  Address 0x6e3c5c0 is 0 bytes inside a block of size 8,220 alloc'd
==11325==    at 0x48CD876: malloc (vg_replace_malloc.c:236)
==11325==    by 0x48DABC9: msgpack_zone_new (zone.c:198)
==11325==    by 0x48D8211: msgpack_unpacker_init (unpack.c:194)
==11325==    by 0x804A08D: msgpack::unpacker::unpacker(unsigned int) (unpack.hpp:187)
==11325==    by 0x8049DC5: main (pack2.cpp:15)

Must be something in the internals of the library. According to valgrind, it's using `auto_ptr`, which is hard-coded to invoke `delete`. You could update your library to C++0x and use `shared_ptr`, which stores custom deleters and can handle `malloc()`ed memory, too. — Kerrek SB, Jul 22 '11 at 14:48

score 2 · Answer 1 · answered Jul 22 '11 at 15:09

2

Looks like everything is ok in this example. According to valgrind call traces, the bug is somewere inside Msgpack library.

answered Jul 22 '11 at 15:09

ks1322

33,961
14
109
164

score 0 · Accepted Answer · answered Aug 05 '13 at 20:30

0

issue was fixed in new version https://github.com/msgpack/msgpack/pull/90

answered Aug 05 '13 at 20:30

Andrey Starostin

113
5

Mismatched free()/delete in MsgPack

2 Answers2