Call sysctl_head_finish on error

This error path returned directly instead of calling sysctl_head_finish().

Fixes: ef9d965bc8 ("sysctl: reject gigantic reads/write to sysctl files")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/proc/proc_sysctl.c

@@ -566,8 +566,9 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *ubuf,
 		goto out;
 
 	/* don't even try if the size is too large */
-	if (count > KMALLOC_MAX_SIZE)
-		return -ENOMEM;
+	error = -ENOMEM;
+	if (count >= KMALLOC_MAX_SIZE)
+		goto out;
 
 	if (write) {
 		kbuf = memdup_user_nul(ubuf, count);
@@ -576,7 +577,6 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *ubuf,
 			goto out;
 		}
 	} else {
-		error = -ENOMEM;
 		kbuf = kzalloc(count, GFP_KERNEL);
 		if (!kbuf)
 			goto out;