kexec: fix memory leak in function kimage_normal_alloc

If kimage_normal_alloc() fails to alloc pages for image->swap_page, it
should call kimage_free_page_list() to free allocated pages in
image->control_pages list before it frees image.
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/kexec.c

@@ -229,6 +229,8 @@ static int do_kimage_alloc(struct kimage **rimage, unsigned long entry,
 
 }
 
+static void kimage_free_page_list(struct list_head *list);
+
 static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
 				unsigned long nr_segments,
 				struct kexec_segment __user *segments)
@@ -252,22 +254,22 @@ static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
 					   get_order(KEXEC_CONTROL_PAGE_SIZE));
 	if (!image->control_code_page) {
 		printk(KERN_ERR "Could not allocate control_code_buffer\n");
-		goto out;
+		goto out_free;
 	}
 
 	image->swap_page = kimage_alloc_control_pages(image, 0);
 	if (!image->swap_page) {
 		printk(KERN_ERR "Could not allocate swap buffer\n");
-		goto out;
+		goto out_free;
 	}
 
-	result = 0;
- out:
-	if (result == 0)
-		*rimage = image;
-	else
-		kfree(image);
+	*rimage = image;
+	return 0;
 
+out_free:
+	kimage_free_page_list(&image->control_pages);
+	kfree(image);
+out:
 	return result;
 }