diff --git a/ldblib.c b/ldblib.c
index ada35250..d045a82e 100644
--- a/ldblib.c
+++ b/ldblib.c
@@ -167,7 +167,8 @@ static int db_getinfo (lua_State *L) {
     return luaL_argerror(L, arg+2, "invalid option");
   lua_newtable(L);  /* table to collect results */
   if (strchr(options, 'S')) {
-    settabss(L, "source", ar.source);
+    lua_pushlstring(L, ar.source, ar.srclen);
+    lua_setfield(L, -2, "source");
     settabss(L, "short_src", ar.short_src);
     settabsi(L, "linedefined", ar.linedefined);
     settabsi(L, "lastlinedefined", ar.lastlinedefined);
diff --git a/ldebug.c b/ldebug.c
index bd471e0c..6cd4e071 100644
--- a/ldebug.c
+++ b/ldebug.c
@@ -262,18 +262,26 @@ LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
 static void funcinfo (lua_Debug *ar, Closure *cl) {
   if (noLuaClosure(cl)) {
     ar->source = "=[C]";
+    ar->srclen = LL("=[C]");
     ar->linedefined = -1;
     ar->lastlinedefined = -1;
     ar->what = "C";
   }
   else {
     const Proto *p = cl->l.p;
-    ar->source = p->source ? getstr(p->source) : "=?";
+    if (p->source) {
+      ar->source = getstr(p->source);
+      ar->srclen = tsslen(p->source);
+    }
+    else {
+      ar->source = "=?";
+      ar->srclen = LL("=?");
+    }
     ar->linedefined = p->linedefined;
     ar->lastlinedefined = p->lastlinedefined;
     ar->what = (ar->linedefined == 0) ? "main" : "Lua";
   }
-  luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
+  luaO_chunkid(ar->short_src, ar->source, ar->srclen);
 }
 
 
@@ -750,7 +758,7 @@ const char *luaG_addinfo (lua_State *L, const char *msg, TString *src,
                                         int line) {
   char buff[LUA_IDSIZE];
   if (src)
-    luaO_chunkid(buff, getstr(src), LUA_IDSIZE);
+    luaO_chunkid(buff, getstr(src), tsslen(src));
   else {  /* no source available; use "?" instead */
     buff[0] = '?'; buff[1] = '\0';
   }
diff --git a/llimits.h b/llimits.h
index 3df873db..cc983972 100644
--- a/llimits.h
+++ b/llimits.h
@@ -65,6 +65,10 @@ typedef signed char ls_byte;
 #define ispow2(x)	(((x) & ((x) - 1)) == 0)
 
 
+/* number of chars of a literal string without the ending \0 */
+#define LL(x)   (sizeof(x)/sizeof(char) - 1)
+
+
 /*
 ** conversion of pointer to unsigned integer:
 ** this is for hashing only; there is no problem if the integer
diff --git a/lobject.c b/lobject.c
index 5d340de6..67c37124 100644
--- a/lobject.c
+++ b/lobject.c
@@ -473,45 +473,42 @@ const char *luaO_pushfstring (lua_State *L, const char *fmt, ...) {
 }
 
 
-/* number of chars of a literal string without the ending \0 */
-#define LL(x)	(sizeof(x)/sizeof(char) - 1)
-
 #define RETS	"..."
 #define PRE	"[string \""
 #define POS	"\"]"
 
 #define addstr(a,b,l)	( memcpy(a,b,(l) * sizeof(char)), a += (l) )
 
-void luaO_chunkid (char *out, const char *source, size_t bufflen) {
-  size_t l = strlen(source);
+void luaO_chunkid (char *out, const char *source, size_t srclen) {
+  size_t bufflen = LUA_IDSIZE;  /* free space in buffer */
   if (*source == '=') {  /* 'literal' source */
-    if (l <= bufflen)  /* small enough? */
-      memcpy(out, source + 1, l * sizeof(char));
+    if (srclen <= bufflen)  /* small enough? */
+      memcpy(out, source + 1, srclen * sizeof(char));
     else {  /* truncate it */
       addstr(out, source + 1, bufflen - 1);
       *out = '\0';
     }
   }
   else if (*source == '@') {  /* file name */
-    if (l <= bufflen)  /* small enough? */
-      memcpy(out, source + 1, l * sizeof(char));
+    if (srclen <= bufflen)  /* small enough? */
+      memcpy(out, source + 1, srclen * sizeof(char));
     else {  /* add '...' before rest of name */
       addstr(out, RETS, LL(RETS));
       bufflen -= LL(RETS);
-      memcpy(out, source + 1 + l - bufflen, bufflen * sizeof(char));
+      memcpy(out, source + 1 + srclen - bufflen, bufflen * sizeof(char));
     }
   }
   else {  /* string; format as [string "source"] */
     const char *nl = strchr(source, '\n');  /* find first new line (if any) */
     addstr(out, PRE, LL(PRE));  /* add prefix */
     bufflen -= LL(PRE RETS POS) + 1;  /* save space for prefix+suffix+'\0' */
-    if (l < bufflen && nl == NULL) {  /* small one-line source? */
-      addstr(out, source, l);  /* keep it */
+    if (srclen < bufflen && nl == NULL) {  /* small one-line source? */
+      addstr(out, source, srclen);  /* keep it */
     }
     else {
-      if (nl != NULL) l = nl - source;  /* stop at first newline */
-      if (l > bufflen) l = bufflen;
-      addstr(out, source, l);
+      if (nl != NULL) srclen = nl - source;  /* stop at first newline */
+      if (srclen > bufflen) srclen = bufflen;
+      addstr(out, source, srclen);
       addstr(out, RETS, LL(RETS));
     }
     memcpy(out, POS, (LL(POS) + 1) * sizeof(char));
diff --git a/lobject.h b/lobject.h
index 53e67932..403b6047 100644
--- a/lobject.h
+++ b/lobject.h
@@ -747,7 +747,7 @@ LUAI_FUNC void luaO_tostring (lua_State *L, TValue *obj);
 LUAI_FUNC const char *luaO_pushvfstring (lua_State *L, const char *fmt,
                                                        va_list argp);
 LUAI_FUNC const char *luaO_pushfstring (lua_State *L, const char *fmt, ...);
-LUAI_FUNC void luaO_chunkid (char *out, const char *source, size_t len);
+LUAI_FUNC void luaO_chunkid (char *out, const char *source, size_t srclen);
 
 
 #endif
diff --git a/lua.h b/lua.h
index 7c4a13bc..ec31c781 100644
--- a/lua.h
+++ b/lua.h
@@ -469,6 +469,7 @@ struct lua_Debug {
   const char *namewhat;	/* (n) 'global', 'local', 'field', 'method' */
   const char *what;	/* (S) 'Lua', 'C', 'main', 'tail' */
   const char *source;	/* (S) */
+  size_t srclen;	/* (S) */
   int currentline;	/* (l) */
   int linedefined;	/* (S) */
   int lastlinedefined;	/* (S) */