Re: [PATCH] libceph, ceph: potential dereference of null pointer

[Jeff Layton]

On Thu, 2021-12-09 at 10:50 +0800, Jiasheng Jiang wrote:
> The return value of kzalloc() needs to be checked.
> To avoid use of null pointer in case of the failure of alloc.
> 
> Fixes: 3d14c5d2b6e1 ("ceph: factor out libceph from Ceph file system")
> Signed-off-by: Jiasheng Jiang <jiasheng@xxxxxxxxxxx>
> ---
>  net/ceph/osd_client.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
> index ff8624a7c964..3203e8a34370 100644
> --- a/net/ceph/osd_client.c
> +++ b/net/ceph/osd_client.c
> @@ -1234,6 +1234,8 @@ static struct ceph_osd *create_osd(struct ceph_osd_client *osdc, int onum)
>  	WARN_ON(onum == CEPH_HOMELESS_OSD);
>  
>  	osd = kzalloc(sizeof(*osd), GFP_NOIO | __GFP_NOFAIL);
> +	if (!osd)
> +		return NULL;
>  	osd_init(osd);
>  	osd->o_osdc = osdc;
>  	osd->o_osd = onum;

__GFP_NOFAIL should ensure that it never returns NULL, right?

Also, if you're going to fix this up to handle that error then you
probably also need to fix lookup_create_osd to handle a NULL return from
create_osd as well.
-- 
Jeff Layton <jlayton@xxxxxxxxxx>