Re: [PATCH] scsi: iscsi: fix inappropriate use of put_device

[Mike Christie]

On 11/20/20 1:48 AM, Qinglang Miao wrote:
> kfree(conn) is called inside put_device(&conn->dev) so that
> another one would cause use-after-free. Besides, device_unregister
> should be used here rather than put_device.
> 
> Fixes: f3c893e3dbb5 ("scsi: iscsi: Fail session and connection on transport registration failure")
> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> Signed-off-by: Qinglang Miao <miaoqinglang@xxxxxxxxxx>
> ---
>  drivers/scsi/scsi_transport_iscsi.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
> index 2eb3e4f93..2e68c0a87 100644
> --- a/drivers/scsi/scsi_transport_iscsi.c
> +++ b/drivers/scsi/scsi_transport_iscsi.c
> @@ -2313,7 +2313,9 @@ iscsi_create_conn(struct iscsi_cls_session *session, int dd_size, uint32_t cid)
>  	return conn;
>  
>  release_conn_ref:
> -	put_device(&conn->dev);
> +	device_unregister(&conn->dev);
> +	put_device(&session->dev);
> +	return NULL;
>  release_parent_ref:
>  	put_device(&session->dev);
>  free_conn:
> 

Reviewed-by: Mike Christie <michael.christie@xxxxxxxxxx>