Re: [PATCH] libceph: potential NULL dereference in ceph_msg_data_create()

[Ilya Dryomov]

On Mon, Jul 17, 2017 at 10:13 AM, Dan Carpenter
 wrote:
> If kmem_cache_zalloc() returns NULL then the INIT_LIST_HEAD(>links);
> will Oops.  The callers aren't really prepared for NULL returns so it
> doesn't make a lot of difference in real life.
>
> Fixes: 5240d9f95dfe ("libceph: replace message data pointer with list")
> Signed-off-by: Dan Carpenter 
>
> diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
> index 0c31035bbfee..b7cc615d42ef 100644
> --- a/net/ceph/messenger.c
> +++ b/net/ceph/messenger.c
> @@ -3203,8 +3203,10 @@ static struct ceph_msg_data *ceph_msg_data_create(enum 
> ceph_msg_data_type type)
> return NULL;
>
> data = kmem_cache_zalloc(ceph_msg_data_cache, GFP_NOFS);
> -   if (data)
> -   data->type = type;
> +   if (!data)
> +   return NULL;
> +
> +   data->type = type;
> INIT_LIST_HEAD(>links);
>
> return data;

Applied.

Thanks,

Ilya

[PATCH] libceph: potential NULL dereference in ceph_msg_data_create()

[Dan Carpenter]

If kmem_cache_zalloc() returns NULL then the INIT_LIST_HEAD(>links);
will Oops.  The callers aren't really prepared for NULL returns so it
doesn't make a lot of difference in real life.

Fixes: 5240d9f95dfe ("libceph: replace message data pointer with list")
Signed-off-by: Dan Carpenter 

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 0c31035bbfee..b7cc615d42ef 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -3203,8 +3203,10 @@ static struct ceph_msg_data *ceph_msg_data_create(enum 
ceph_msg_data_type type)
return NULL;
 
data = kmem_cache_zalloc(ceph_msg_data_cache, GFP_NOFS);
-   if (data)
-   data->type = type;
+   if (!data)
+   return NULL;
+
+   data->type = type;
INIT_LIST_HEAD(>links);
 
return data;