flat: fix unmap len in load error path

The data chunk is mmaped with 'len' which remains unchanged, so use that
when unmapping in the error path rather than trying to recalculate (and
incorrectly so) the value used originally.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Acked-by: NDavid McCullough <davidm@snapgear.com>
Acked-by: NGreg Ungerer <gerg@uclinux.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/binfmt_flat.c

@@ -596,7 +596,7 @@ static int load_flat_file(struct linux_binprm * bprm,
 		if (IS_ERR_VALUE(result)) {
 			printk("Unable to read data+bss, errno %d\n", (int)-result);
 			do_munmap(current->mm, textpos, text_len);
-			do_munmap(current->mm, realdatastart, data_len + extra);
+			do_munmap(current->mm, realdatastart, len);
 			ret = result;
 			goto err;
 		}