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From: Coly Li <colyli@suse.de>
To: axboe@kernel.dk
Cc: linux-bcache@vger.kernel.org, linux-block@vger.kernel.org,
	Zheng Wang <zyytlz.wz@163.com>,
	stable@vger.kernel.org, Coly Li <colyli@suse.de>
Subject: [PATCH 5/6] bcache: Fix __bch_btree_node_alloc to make the failure behavior consistent
Date: Thu, 15 Jun 2023 20:12:22 +0800	[thread overview]
Message-ID: <20230615121223.22502-6-colyli@suse.de> (raw)
In-Reply-To: <20230615121223.22502-1-colyli@suse.de>

From: Zheng Wang <zyytlz.wz@163.com>

In some specific situation, the return value of __bch_btree_node_alloc may
be NULL. This may lead to poential NULL pointer dereference in caller
 function like a calling chaion :
 btree_split->bch_btree_node_alloc->__bch_btree_node_alloc.

Fix it by initialize return value in __bch_btree_node_alloc before return.

Fixes: cafe56359144 ("bcache: A block layer cache")
Cc: stable@vger.kernel.org
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Signed-off-by: Coly Li <colyli@suse.de>
---
 drivers/md/bcache/btree.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 7c21e54468bf..0ddf91204782 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1090,10 +1090,12 @@ struct btree *__bch_btree_node_alloc(struct cache_set *c, struct btree_op *op,
 				     struct btree *parent)
 {
 	BKEY_PADDED(key) k;
-	struct btree *b = ERR_PTR(-EAGAIN);
+	struct btree *b;
 
 	mutex_lock(&c->bucket_lock);
 retry:
+	/* return ERR_PTR(-EAGAIN) when it fails */
+	b = ERR_PTR(-EAGAIN);
 	if (__bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, wait))
 		goto err;
 
-- 
2.35.3


  parent reply	other threads:[~2023-06-15 12:13 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-15 12:12 [PATCH 0/6] bcache-next 20230615 Coly Li
2023-06-15 12:12 ` [PATCH 1/6] bcache: Convert to use sysfs_emit()/sysfs_emit_at() APIs Coly Li
2023-06-15 12:12 ` [PATCH 2/6] bcache: make kobj_type structures constant Coly Li
2023-06-15 12:12 ` [PATCH 3/6] bcache: Remove dead references to cache_readaheads Coly Li
2023-06-15 12:12 ` [PATCH 4/6] bcache: Remove some unnecessary NULL point check for the return value of __bch_btree_node_alloc-related pointer Coly Li
2023-06-15 12:12 ` Coly Li [this message]
2023-06-15 12:12 ` [PATCH 6/6] bcache: fixup btree_cache_wait list damage Coly Li
2023-06-15 13:33 ` [PATCH 0/6] bcache-next 20230615 Jens Axboe

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