module: prevent warning when finit_module a 0 sized file

sashalevin · rustyrussell · commit 52441fa8f2f1 · 2013-01-03T11:10:32.000+10:30
If we try to finit_module on a file sized 0 bytes vmalloc will
scream and spit out a warning.

Since modules have to be bigger than 0 bytes anyways we can just
check that beforehand and avoid the warning.

Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
Signed-off-by: Rusty Russell &lt;rusty@rustcorp.com.au&gt;
diff --git a/kernel/module.c b/kernel/module.c
@@ -2527,6 +2527,13 @@ static int copy_module_from_fd(int fd, struct load_info *info)
 		err = -EFBIG;
 		goto out;
 	}
+
+	/* Don't hand 0 to vmalloc, it whines. */
+	if (stat.size == 0) {
+		err = -EINVAL;
+		goto out;
+	}
+
 	info->hdr = vmalloc(stat.size);
 	if (!info->hdr) {
 		err = -ENOMEM;
