bug: crash while calling function from yielded state with line hook set

[Anatoly Ahmedov <ludd@...>]

    Hello.

    Call to lua function from c using yielded lua_State works fine. But 
same call with line hook set crashes in lvm.c line 71.
    Lua version 5.1.4

    Code to reproduce:

#include <stdio.h>

extern "C" {
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
}

void testHook(lua_State *L, lua_Debug *ar)
{
    static int c = 0;
    c++;
}

int main(void)
{
    lua_State* l = lua_open();
    luaopen_base(l);

    lua_sethook(l, testHook, LUA_MASKLINE, 0);    //works fine when 
this line is commented

    const char* script =   "function func()    \
                                print('func1')    \
                            end    \
                            function threadFunc()    \
                                print('before yield')    \
                                coroutine.yield()    \
                                print('after yield')    \
                            end    \
                            thread = coroutine.create(threadFunc)    \
                            coroutine.resume(thread)    \
                            ";
    int rez = luaL_dostring(l, script);
    if (rez) {
        return 1;
    }

    lua_getglobal(l, "thread");
    lua_State* thread = lua_tothread(l, -1);

    lua_getglobal(thread, "func");    //will work too if "l" state is 
used....
    if (lua_pcall(thread, 0, 0, 0)) {
        return 1;
    }

    lua_resume(thread, 0);

    return 0;
}

    I believe that it should either work in both cases (wonder how?...) 
or report error even if no hook set...

--
WBR, Anatoly Ahmedov