Lua C API内存泄漏?(valgrind)

Lua C API Memory Leak? (valgrind)

本文关键字：valgrind 泄漏 API 内存 Lua      更新时间：2023-10-16

我想写一个C程序与Lua内嵌…然后，我尝试了一个非常简单的程序来启动，它只是创建Lua上下文，然后销毁它:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
extern "C" {
    #include <lua.h>
    #include <lauxlib.h>
    #include <lualib.h>
}
int main(int argc, char *argv[]) {
    lua_State *L = lua_open();
    luaL_openlibs(L);
    lua_close(L);
    fprintf(stderr, "%s: %dn", __FILE__, __LINE__);
    return(0);
}

我像这样编译它:(我实际上使用的是Torch7，所以…)

g++ -c -g3 -O2 -Wall -Werror -I/usr/local/torch/install/include/ -fPIC pure_lua_test.C -o pure_lua_test.o
g++ -g3 -O2 -Wall -Werror -I/usr/local/torch/install/include/ -fPIC -o pure_lua_test pure_lua_test.o -L/usr/local/torch/install/lib/ -lluajit

当我单独运行它时，它打印

pure_lua_test.C: 16

如预期，(就在返回之前)。

但是，当我用valgrind运行它时，(作为valgrind ./pure_lua_test)

我

==9165== Memcheck, a memory error detector
==9165== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==9165== Using Valgrind-3.10.0.SVN and LibVEX; rerun with -h for copyright info
==9165== Command: ./pure_lua_test
==9165== 
==9165== Invalid read of size 4
==9165==    at 0x4E9EE97: lua_pushcclosure (in /usr/local/src/torch-2015-05-25/install/lib/libluajit.so)
==9165==    by 0x4EB4CDD: luaL_openlibs (in /usr/local/src/torch-2015-05-25/install/lib/libluajit.so)
==9165==    by 0x400700: main (pure_lua_test.C:13)
==9165==  Address 0x8 is not stack'd, malloc'd or (recently) free'd
==9165== 
==9165== 
==9165== Process terminating with default action of signal 11 (SIGSEGV)
==9165==  Access not within mapped region at address 0x8
==9165==    at 0x4E9EE97: lua_pushcclosure (in /usr/local/src/torch-2015-05-25/install/lib/libluajit.so)
==9165==    by 0x4EB4CDD: luaL_openlibs (in /usr/local/src/torch-2015-05-25/install/lib/libluajit.so)
==9165==    by 0x400700: main (pure_lua_test.C:13)
==9165==  If you believe this happened as a result of a stack
==9165==  overflow in your program's main thread (unlikely but
==9165==  possible), you can try to increase the size of the
==9165==  main thread stack using the --main-stacksize= flag.
==9165==  The main thread stack size used in this run was 8388608.
==9165== 
==9165== HEAP SUMMARY:
==9165==     in use at exit: 0 bytes in 0 blocks
==9165==   total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==9165== 
==9165== All heap blocks were freed -- no leaks are possible
==9165== 
==9165== For counts of detected and suppressed errors, rerun with: -v
==9165== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

有人知道发生了什么事吗?为什么在valgrind中使用SIGSEGV ?这是我该担心的吗?基本上，我希望验证我为Torch编写的插件没有内存泄漏……但是，如果这个失败了，那么，我就卡住了。

这个问题的原因似乎是Valgrind，而不是LuaJIT。Valgrind正在阻塞MAP_32BIT，这会破坏LuaJIT。为了演示，在lua_State * L上添加对NULL的检查，您将看到它在Valgrind下运行时为NULL，而在常规运行时为非NULL。

这是我对你的样品所做的修改:

if(L == NULL) {
    printf("Could not create luaL_newstate()n");
} else {
    luaL_openlibs(L);
    lua_close(L);
    printf("I can create luaL_newstate fine!n");
}

当我正常运行时:

$ ./pure_lua_test 
I can create luaL_newstate fine!

但是当我在Valgrind下运行时:

$ valgrind ./pure_lua_test
==8211== Memcheck, a memory error detector
==8211== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==8211== Using Valgrind-3.10.1 and LibVEX; rerun with -h for copyright info
==8211== Command: ./pure_lua_test
==8211== 
Could not create luaL_newstate()
==8211==

GDB还报告应用程序已退出:

(gdb) run
Starting program: /tmp/pure_lua_test 
I can create luaL_newstate fine!
[Inferior 1 (process 8621) exited normally]

这是一个完整的MCVE:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
extern "C" {
        #include <lua.h>
        #include <lauxlib.h>
        #include <lualib.h>
}
int main(int argc, char *argv[]) {
    lua_State *L;
    L = luaL_newstate();
    if(L == NULL) {
        printf("Could not create luaL_newstate()n");
    } else {
        luaL_openlibs(L);
        lua_close(L);
        printf("I can create luaL_newstate fine!n");
    }
    return(0);
}

这是一篇关于MAP_32BIT的好文章。

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