diff --git a/src/mesa/main/objectlabel.c b/src/mesa/main/objectlabel.c
index 90d9e09f57d..d9e42cfe4a6 100644
--- a/src/mesa/main/objectlabel.c
+++ b/src/mesa/main/objectlabel.c
@@ -86,21 +86,38 @@ set_label(struct gl_context *ctx, char **labelPtr, const char *label,
 
 /**
  * Helper for _mesa_GetObjectLabel() and _mesa_GetObjectPtrLabel().
+ * \param src  the src label (may be null)
+ * \param dst  pointer to dest buffer (may be null)
+ * \param length  returns length of label (may be null)
+ * \param bufsize  size of dst buffer
  */
 static void
-copy_label(char **labelPtr, char *label, int *length, int bufSize)
+copy_label(const GLchar *src, GLchar *dst, GLsizei *length, GLsizei bufSize)
 {
    int labelLen = 0;
 
-   if (*labelPtr)
-      labelLen = strlen(*labelPtr);
+   /* From http://www.opengl.org/registry/specs/KHR/debug.txt:
+    * "If <length> is NULL, no length is returned. The maximum number of
+    * characters that may be written into <label>, including the null
+    * terminator, is specified by <bufSize>. If no debug label was specified
+    * for the object then <label> will contain a null-terminated empty string,
+    * and zero will be returned in <length>. If <label> is NULL and <length>
+    * is non-NULL then no string will be returned and the length of the label
+    * will be returned in <length>."
+    */
 
-   if (label) {
-      if (bufSize <= labelLen)
-         labelLen =  bufSize-1;
+   if (src)
+      labelLen = strlen(src);
 
-      memcpy(label, *labelPtr, labelLen);
-      label[labelLen] = '\0';
+   if (dst) {
+      if (src) {
+         if (bufSize <= labelLen)
+            labelLen = bufSize - 1;
+
+         memcpy(dst, src, labelLen);
+      }
+
+      dst[labelLen] = '\0';
    }
 
    if (length)
@@ -243,7 +260,7 @@ _mesa_GetObjectLabel(GLenum identifier, GLuint name, GLsizei bufSize,
    if (!labelPtr)
       return;
 
-   copy_label(labelPtr, label, length, bufSize);
+   copy_label(*labelPtr, label, length, bufSize);
 }
 
 void GLAPIENTRY
@@ -278,5 +295,5 @@ _mesa_GetObjectPtrLabel(const void *ptr, GLsizei bufSize, GLsizei *length,
 
    labelPtr = &syncObj->Label;
 
-   copy_label(labelPtr, label, length, bufSize);
+   copy_label(*labelPtr, label, length, bufSize);
 }