[dpdk-stable] [PATCH v2] [18.11] net/mlx5: fix xstats reset reinitialization

[Viacheslav Ovsiienko <viacheslavo@nvidia.com>]

From: Shiri Kuzin <shirik@nvidia.com>

[ upstream commit 42dcd453d9b63841a5460a6ca3872eb7648d73bd ]

The mlx5_xstats_reset clears the device extended statistics.
In this function the driver may reinitialize the structures
that are used to read device counters.

In case of reinitialization, the number of counters may
change, which wouldn't be taken into account by the
reset API callback and can cause a segmentation fault.

This issue is fixed by allocating the counters size after
the reinitialization.

Fixes: a4193ae3bc4f ("net/mlx5: support extended statistics")

Reported-by: Ralf Hoffmann <ralf.hoffmann@allegro-packets.com>
Signed-off-by: Shiri Kuzin <shirik@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>
---
 drivers/net/mlx5/mlx5_stats.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_stats.c b/drivers/net/mlx5/mlx5_stats.c
index 0b1fe3d..5e3a0d2 100644
--- a/drivers/net/mlx5/mlx5_stats.c
+++ b/drivers/net/mlx5/mlx5_stats.c
@@ -480,8 +480,7 @@
 	struct mlx5_xstats_ctrl *xstats_ctrl = &priv->xstats_ctrl;
 	int stats_n;
 	unsigned int i;
-	unsigned int n = xstats_ctrl->mlx5_stats_n;
-	uint64_t counters[n];
+	uint64_t *counters;
 	int ret;
 
 	stats_n = mlx5_ethtool_get_stats_n(dev);
@@ -492,14 +491,26 @@
 	}
 	if (xstats_ctrl->stats_n != stats_n)
 		mlx5_stats_init(dev);
+	counters =  rte_malloc("xstats_counters",
+			       sizeof(*counters) * xstats_ctrl->mlx5_stats_n,
+			       SOCKET_ID_ANY);
+	if (!counters) {
+		DRV_LOG(WARNING, "port %u unable to allocate memory "
+				 "for xstats counters",
+				 dev->data->port_id);
+		rte_errno = ENOMEM;
+		return;
+	}
 	ret = mlx5_read_dev_counters(dev, counters);
 	if (ret) {
 		DRV_LOG(ERR, "port %u cannot read device counters: %s",
 			dev->data->port_id, strerror(rte_errno));
+		rte_free(counters);
 		return;
 	}
-	for (i = 0; i != n; ++i)
+	for (i = 0; i != xstats_ctrl->mlx5_stats_n; ++i)
 		xstats_ctrl->base[i] = counters[i];
+	rte_free(counters);
 }
 
 /**
-- 
1.8.3.1