It decodes "\n" as 0, which is bad, because stray echo into backlight
will turn your backlight off, etc...
Signed-off-by: Pavel Machek <pavel@suse.cz>
Cc: Yi Yang <yi.y.yang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
                return -EINVAL;
 
        val = simple_strtoul(cp, &tail, base);
+       if (tail == cp)
+               return -EINVAL;
        if ((*tail == '\0') ||
                ((len == (size_t)(tail - cp) + 1) && (*tail == '\n'))) {
                *res = val;
                return -EINVAL;
 
        val = simple_strtoull(cp, &tail, base);
+       if (tail == cp)
+               return -EINVAL;
        if ((*tail == '\0') ||
                ((len == (size_t)(tail - cp) + 1) && (*tail == '\n'))) {
                *res = val;