The return values of copy_to_user() and copy_from_user() cannot be negative.
Found using the following semantich patch:
<spml>
@exists@
identifier ret;
statement S;
expression E;
@@
(
* ret = copy_to_user(...);
|
* ret = copy_from_user(...);
)
... when != ret = E
    when != if (ret) { <+... ret = E; ...+> }
* if (ret < 0)
  S
</spml>
Signed-off-by: Cyril Roelandt <tipecaml@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
                                solo_enc->osd_text[OSD_TEXT_MAX] = '\0';
                                if (!err)
                                        err = solo_osd_print(solo_enc);
+                               else
+                                       err = -EFAULT;
                        }
                        break;
                default:
                                err = copy_to_user(ctrl->string,
                                                   solo_enc->osd_text,
                                                   OSD_TEXT_MAX);
+                               if (err)
+                                       err = -EFAULT;
                        }
                        break;
                default: