[dpdk-stable] patch 'net/mlx5: fix mbuf replenishment check for zipped CQE' has been queued to stable release 20.11.4

[Xueming Li]

Hi,

FYI, your patch has been queued to stable release 20.11.4

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 11/12/21. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/steevenlee/dpdk

This queued commit can be viewed at:
https://github.com/steevenlee/dpdk/commit/f50cec54fd7ac0ba16ac15580c1e60b501aeb53b

Thanks.

Xueming Li <xuemingl at nvidia.com>

---
>From f50cec54fd7ac0ba16ac15580c1e60b501aeb53b Mon Sep 17 00:00:00 2001
From: Alexander Kozyrev <akozyrev at nvidia.com>
Date: Wed, 4 Aug 2021 09:23:16 +0300
Subject: [PATCH] net/mlx5: fix mbuf replenishment check for zipped CQE
Cc: Xueming Li <xuemingl at nvidia.com>

[ upstream commit 828274b70ad10bc1ae54c4b4b446e7f42f181521 ]

A core dump is being generated with the following call stack:
0 _mm256_storeu_si256 (__A=..., __P=0x80)
1 rte_mov32 (src=0x2299c9140 "", dst=0x80)
2 rte_memcpy_aligned (n=60, src=0x2299c9140, dst=0x80)
3 rte_memcpy (n=60, src=0x2299c9140, dst=0x80)
4 mprq_buf_to_pkt (strd_cnt=1, strd_idx=0, buf=0x2299c8a00, len=60,
pkt=0x18345f0c0, rxq=0x18345ef40)
5 rxq_copy_mprq_mbuf_v (rxq=0x18345ef40, pkts=0x7f76e0ff6d18, pkts_n=5)
6 rxq_burst_mprq_v (rxq=0x18345ef40, pkts=0x7f76e0ff6d18, pkts_n=46,
err=0x7f76e0ff6a28, no_cq=0x7f76e0ff6a27)
7 mlx5_rx_burst_mprq_vec (dpdk_rxq=0x18345ef40, pkts=0x7f76e0ff6a88,
pkts_n=128)
8 rte_eth_rx_burst (nb_pkts=128, rx_pkts=0x7f76e0ff6a88,
queue_id=<optimized out>, port_id=<optimized out>)

This crash is caused by an attempt to copy previously uncompressed CQEs
into non-allocated mbufs. There is a check to make sure we only use
allocated mbufs in the rxq_burst_mprq_v() function, but it is done only
before the main processing loop. Leftovers of compressed CQEs session are
handled before that loop and may lead to the mbufs overflow as seen.

Move the check for replenished mbufs up to protect uncompressed CQEs
session leftovers from accessing non-allocated mbufs after the
mlx5_rx_mprq_replenish_bulk_mbuf() function is invoked.

Bugzilla ID: 746
Fixes: 0f20acbf5eda ("net/mlx5: implement vectorized MPRQ burst")

Signed-off-by: Alexander Kozyrev <akozyrev at nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
---
 drivers/net/mlx5/mlx5_rxtx_vec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_rxtx_vec.c b/drivers/net/mlx5/mlx5_rxtx_vec.c
index b8b555690e..1536a462dc 100644
--- a/drivers/net/mlx5/mlx5_rxtx_vec.c
+++ b/drivers/net/mlx5/mlx5_rxtx_vec.c
@@ -442,6 +442,8 @@ rxq_burst_mprq_v(struct mlx5_rxq_data *rxq, struct rte_mbuf **pkts,
 	rte_prefetch0(cq + 3);
 	pkts_n = RTE_MIN(pkts_n, MLX5_VPMD_RX_MAX_BURST);
 	mlx5_rx_mprq_replenish_bulk_mbuf(rxq);
+	/* Not to move past the allocated mbufs. */
+	pkts_n = RTE_MIN(pkts_n, rxq->elts_ci - rxq->rq_pi);
 	/* See if there're unreturned mbufs from compressed CQE. */
 	rcvd_pkt = rxq->decompressed;
 	if (rcvd_pkt > 0) {
@@ -457,8 +459,6 @@ rxq_burst_mprq_v(struct mlx5_rxq_data *rxq, struct rte_mbuf **pkts,
 	/* Not to cross queue end. */
 	pkts_n = RTE_MIN(pkts_n, elts_n - elts_idx);
 	pkts_n = RTE_MIN(pkts_n, q_n - cq_idx);
-	/* Not to move past the allocated mbufs. */
-	pkts_n = RTE_MIN(pkts_n, rxq->elts_ci - rxq->rq_pi);
 	if (!pkts_n) {
 		*no_cq = !cp_pkt;
 		return cp_pkt;
-- 
2.33.0

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2021-11-10 14:17:02.487895876 +0800
+++ 0008-net-mlx5-fix-mbuf-replenishment-check-for-zipped-CQE.patch	2021-11-10 14:17:01.740747155 +0800
@@ -1 +1 @@
-From 828274b70ad10bc1ae54c4b4b446e7f42f181521 Mon Sep 17 00:00:00 2001
+From f50cec54fd7ac0ba16ac15580c1e60b501aeb53b Mon Sep 17 00:00:00 2001
@@ -4,0 +5,3 @@
+Cc: Xueming Li <xuemingl at nvidia.com>
+
+[ upstream commit 828274b70ad10bc1ae54c4b4b446e7f42f181521 ]
@@ -33 +35,0 @@
-Cc: stable at dpdk.org
@@ -42 +44 @@
-index e1b6d5422a..ecd273e00a 100644
+index b8b555690e..1536a462dc 100644
@@ -45 +47 @@
-@@ -448,6 +448,8 @@ rxq_burst_mprq_v(struct mlx5_rxq_data *rxq, struct rte_mbuf **pkts,
+@@ -442,6 +442,8 @@ rxq_burst_mprq_v(struct mlx5_rxq_data *rxq, struct rte_mbuf **pkts,
@@ -54 +56 @@
-@@ -463,8 +465,6 @@ rxq_burst_mprq_v(struct mlx5_rxq_data *rxq, struct rte_mbuf **pkts,
+@@ -457,8 +459,6 @@ rxq_burst_mprq_v(struct mlx5_rxq_data *rxq, struct rte_mbuf **pkts,