Re: [PATCH] nvme/rdma: Fix a use after free in nvmet_rdma_write_data_done

[Sagi Grimberg <sagi@grimberg.me>]

> In nvmet_rdma_write_data_done, rsp is recoverd by wc->wr_cqe
> and freed by nvmet_rdma_release_rsp(). But after that, pr_info()
> used the freed chunk's member object and could leak the freed
> chunk address with wc->wr_cqe by computing the offset.
> 
> Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
> ---
>   drivers/nvme/target/rdma.c | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
> index 06b6b742bb21..6c1f3ab7649c 100644
> --- a/drivers/nvme/target/rdma.c
> +++ b/drivers/nvme/target/rdma.c
> @@ -802,9 +802,8 @@ static void nvmet_rdma_write_data_done(struct ib_cq *cq, struct ib_wc *wc)
>   		nvmet_req_uninit(&rsp->req);
>   		nvmet_rdma_release_rsp(rsp);
>   		if (wc->status != IB_WC_WR_FLUSH_ERR) {
> -			pr_info("RDMA WRITE for CQE 0x%p failed with status %s (%d).\n",
> -				wc->wr_cqe, ib_wc_status_msg(wc->status),
> -				wc->status);
> +			pr_info("RDMA WRITE for CQE failed with status %s (%d).\n",
> +				ib_wc_status_msg(wc->status), wc->status);

There is nothing wrong with this reference, wr_cqe is a valid reference
and I think Israel added this for some extra information that may be
useful to him.

Israel? you ok with this removed?

>   			nvmet_rdma_error_comp(queue);
>   		}
>   		return;
>