From: Coly Li <colyli@suse.de>
To: Zheng Wang <zyytlz.wz@163.com>
Cc: Zheng Hacker <hackerzheng666@gmail.com>,
kent.overstreet@gmail.com, linux-bcache@vger.kernel.org,
linux-kernel@vger.kernel.org, alex000young@gmail.com,
stable@vger.kernel.org
Subject: Re: [RESEND PATCH v3] bcache: Fix __bch_btree_node_alloc to make the failure behavior consistent
Date: Sat, 18 Feb 2023 23:22:26 +0800 [thread overview]
Message-ID: <05D7778B-6B00-468B-983D-B00619FA337D@suse.de> (raw)
In-Reply-To: <20230218072335.1537099-1-zyytlz.wz@163.com>
On Sat, Feb 18, 2023 at 03:23:35PM +0800, Zheng Wang wrote:
> 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>
Thanks, I will add this series to my for-next testing queue.
Coly Li
> ---
> v3:
> - Add Cc: stable@vger.kernel.org suggested by Eric
> v2:
> - split patch v1 into two patches to make it clearer suggested by Coly Li
> ---
> 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 147c493a989a..cae25e74b9e0 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;
>
> --
> 2.25.1
>
prev parent reply other threads:[~2023-02-18 15:22 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-18 7:23 [RESEND PATCH v3] bcache: Fix __bch_btree_node_alloc to make the failure behavior consistent Zheng Wang
2023-02-18 15:22 ` Coly Li [this message]
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