fix compat_sys_rt_sigprocmask()

Converting bitmask to 32bit granularity is fine, but we'd better
_do_ something with the result.  Such as "copy it to userland"...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

kernel/signal.c

diff --git a/kernel/signal.c b/kernel/signal.c
index 2a7ae29..8d1b785 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2653,7 +2653,7 @@
 	if (oset) {
 		compat_sigset_t old32;
 		sigset_to_compat(&old32, &old_set);
-		if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
+		if (copy_to_user(oset, &old32, sizeof(compat_sigset_t)))
 			return -EFAULT;
 	}
 	return 0;