From 09fa32a423e8ae1600769effa6fec02a2cb98d7a Mon Sep 17 00:00:00 2001
From: Joe Thornber <ejt@redhat.com>
Date: Fri, 24 Nov 2017 11:05:51 +0000
Subject: [PATCH] [ft-lib/bcache] alloc_block wasn't checking for an empty free
 list

---
 ft-lib/bcache.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/ft-lib/bcache.c b/ft-lib/bcache.c
index ca1921d..6f3c987 100644
--- a/ft-lib/bcache.c
+++ b/ft-lib/bcache.c
@@ -444,8 +444,10 @@ static void exit_free_list(struct bcache *cache)
 
 static struct block *alloc_block(struct bcache *cache)
 {
-	struct block *b = container_of(list_pop(&cache->free), struct block, list);
-	return b;
+	if (list_empty(&cache->free))
+		return NULL;
+
+	return container_of(list_pop(&cache->free), struct block, list);
 }
 
 /*----------------------------------------------------------------