* Re: [PATCHv2 1/1] IB/rxe: avoid double kfree_skb
[not found] <1524717670-10901-1-git-send-email-yanjun.zhu@oracle.com>
@ 2018-04-26 5:22 ` Yanjun Zhu
0 siblings, 0 replies; only message in thread
From: Yanjun Zhu @ 2018-04-26 5:22 UTC (permalink / raw)
To: monis, dledford, jgg, linux-rdma, netdev
Add netdev@vger.kernel.org
On 2018/4/26 12:41, Zhu Yanjun wrote:
> When skb is sent, it will pass the following functions in soft roce.
>
> rxe_send [rdma_rxe]
> ip_local_out
> __ip_local_out
> ip_output
> ip_finish_output
> ip_finish_output2
> dev_queue_xmit
> __dev_queue_xmit
> dev_hard_start_xmit
>
> In the above functions, if error occurs in the above functions or
> iptables rules drop skb after ip_local_out, kfree_skb will be called.
> So it is not necessary to call kfree_skb in soft roce module again.
> Or else crash will occur.
>
> The steps to reproduce:
>
> server client
> --------- ---------
> |1.1.1.1|<----rxe-channel--->|1.1.1.2|
> --------- ---------
>
> On server: rping -s -a 1.1.1.1 -v -C 10000 -S 512
> On client: rping -c -a 1.1.1.1 -v -C 10000 -S 512
>
> The kernel configs CONFIG_DEBUG_KMEMLEAK and
> CONFIG_DEBUG_OBJECTS are enabled on both server and client.
>
> When rping runs, run the following command in server:
>
> iptables -I OUTPUT -p udp --dport 4791 -j DROP
>
> Without this patch, crash will occur.
>
> CC: Srinivas Eeda <srinivas.eeda@oracle.com>
> CC: Junxiao Bi <junxiao.bi@oracle.com>
> Signed-off-by: Zhu Yanjun <yanjun.zhu@oracle.com>
> Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
> ---
> V1->V2: Not only the dropped skb is freed, but also the error skb
> is also freed. So in soft roce, it is not necessary to call
> kfree_skb again.
> ---
> drivers/infiniband/sw/rxe/rxe_req.c | 1 -
> drivers/infiniband/sw/rxe/rxe_resp.c | 6 +-----
> 2 files changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c
> index 7bdaf71..7851999 100644
> --- a/drivers/infiniband/sw/rxe/rxe_req.c
> +++ b/drivers/infiniband/sw/rxe/rxe_req.c
> @@ -728,7 +728,6 @@ int rxe_requester(void *arg)
> rollback_state(wqe, qp, &rollback_wqe, rollback_psn);
>
> if (ret == -EAGAIN) {
> - kfree_skb(skb);
> rxe_run_task(&qp->req.task, 1);
> goto exit;
> }
> diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
> index a65c996..955ff3b 100644
> --- a/drivers/infiniband/sw/rxe/rxe_resp.c
> +++ b/drivers/infiniband/sw/rxe/rxe_resp.c
> @@ -742,7 +742,6 @@ static enum resp_states read_reply(struct rxe_qp *qp,
> err = rxe_xmit_packet(rxe, qp, &ack_pkt, skb);
> if (err) {
> pr_err("Failed sending RDMA reply.\n");
> - kfree_skb(skb);
> return RESPST_ERR_RNR;
> }
>
> @@ -954,10 +953,8 @@ static int send_ack(struct rxe_qp *qp, struct rxe_pkt_info *pkt,
> }
>
> err = rxe_xmit_packet(rxe, qp, &ack_pkt, skb);
> - if (err) {
> + if (err)
> pr_err_ratelimited("Failed sending ack\n");
> - kfree_skb(skb);
> - }
>
> err1:
> return err;
> @@ -1141,7 +1138,6 @@ static enum resp_states duplicate_request(struct rxe_qp *qp,
> if (rc) {
> pr_err("Failed resending result. This flow is not handled - skb ignored\n");
> rxe_drop_ref(qp);
> - kfree_skb(skb_copy);
> rc = RESPST_CLEANUP;
> goto out;
> }
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2018-04-26 5:22 ` [PATCHv2 1/1] IB/rxe: avoid double kfree_skb Yanjun Zhu
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