net: ethernet: ti: icssg: guard PA stat lookups

icssg_ndo_get_stats64() unconditionally calls emac_get_stat_by_name()
with FW PA stat names regardless of whether the PA stats block is
present on the hardware.  emac_get_stat_by_name() already guards the
PA stats lookup with `if (emac->prueth->pa_stats)`; when that pointer
is NULL the lookup falls through to netdev_err() and returns -EINVAL.
Because ndo_get_stats64 is polled regularly by the networking stack
this produces thousands of log entries of the form:

  icssg-prueth icssg1-eth end0: Invalid stats FW_RX_ERROR

A secondary consequence is that the int(-EINVAL) return value is
implicitly widened to a near-ULLONG_MAX unsigned value when accumulated
into the __u64 fields of rtnl_link_stats64, silently corrupting the
rx_errors, rx_dropped and tx_dropped counters reported by `ip -s link`.

Every other PA-aware code path in the driver is already guarded with
the same `if (emac->prueth->pa_stats)` check.  Apply the same guard
here.

Fixes: 0d15a26b247d ("net: ti: icssg-prueth: Add ICSSG FW Stats")
Signed-off-by: Philippe Schenker <philippe.schenker@impulsing.ch>
Reviewed-by: Simon Horman <horms@kernel.org>
Cc: danishanwar@ti.com
Cc: rogerq@kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260618093037.3448858-1-dev@pschenker.ch
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/ti/icssg/icssg_common.c b/drivers/net/ethernet/ti/icssg/icssg_common.c
index 82ddef9c17d54e70006ba92d90c0ceed6920c4ad..9c0280bedefbdbe4596706707d57c865f363bc7c 100644 (file)
--- a/drivers/net/ethernet/ti/icssg/icssg_common.c
+++ b/drivers/net/ethernet/ti/icssg/icssg_common.c
@@ -1652,28 +1652,35 @@ void icssg_ndo_get_stats64(struct net_device *ndev,
        stats->rx_over_errors = emac_get_stat_by_name(emac, "rx_over_errors");
        stats->multicast      = emac_get_stat_by_name(emac, "rx_multicast_frames");
 
-       stats->rx_errors  = ndev->stats.rx_errors +
-                           emac_get_stat_by_name(emac, "FW_RX_ERROR") +
-                           emac_get_stat_by_name(emac, "FW_RX_EOF_SHORT_FRMERR") +
-                           emac_get_stat_by_name(emac, "FW_RX_B0_DROP_EARLY_EOF") +
-                           emac_get_stat_by_name(emac, "FW_RX_EXP_FRAG_Q_DROP") +
-                           emac_get_stat_by_name(emac, "FW_RX_FIFO_OVERRUN");
-       stats->rx_dropped = ndev->stats.rx_dropped +
-                           emac_get_stat_by_name(emac, "FW_DROPPED_PKT") +
-                           emac_get_stat_by_name(emac, "FW_INF_PORT_DISABLED") +
-                           emac_get_stat_by_name(emac, "FW_INF_SAV") +
-                           emac_get_stat_by_name(emac, "FW_INF_SA_DL") +
-                           emac_get_stat_by_name(emac, "FW_INF_PORT_BLOCKED") +
-                           emac_get_stat_by_name(emac, "FW_INF_DROP_TAGGED") +
-                           emac_get_stat_by_name(emac, "FW_INF_DROP_PRIOTAGGED") +
-                           emac_get_stat_by_name(emac, "FW_INF_DROP_NOTAG") +
-                           emac_get_stat_by_name(emac, "FW_INF_DROP_NOTMEMBER");
+       stats->rx_errors  = ndev->stats.rx_errors;
+       stats->rx_dropped = ndev->stats.rx_dropped;
        stats->tx_errors  = ndev->stats.tx_errors;
-       stats->tx_dropped = ndev->stats.tx_dropped +
-                           emac_get_stat_by_name(emac, "FW_RTU_PKT_DROP") +
-                           emac_get_stat_by_name(emac, "FW_TX_DROPPED_PACKET") +
-                           emac_get_stat_by_name(emac, "FW_TX_TS_DROPPED_PACKET") +
-                           emac_get_stat_by_name(emac, "FW_TX_JUMBO_FRM_CUTOFF");
+       stats->tx_dropped = ndev->stats.tx_dropped;
+
+       if (!emac->prueth->pa_stats)
+               return;
+
+       stats->rx_errors  +=
+                       emac_get_stat_by_name(emac, "FW_RX_ERROR") +
+                       emac_get_stat_by_name(emac, "FW_RX_EOF_SHORT_FRMERR") +
+                       emac_get_stat_by_name(emac, "FW_RX_B0_DROP_EARLY_EOF") +
+                       emac_get_stat_by_name(emac, "FW_RX_EXP_FRAG_Q_DROP") +
+                       emac_get_stat_by_name(emac, "FW_RX_FIFO_OVERRUN");
+       stats->rx_dropped +=
+                       emac_get_stat_by_name(emac, "FW_DROPPED_PKT") +
+                       emac_get_stat_by_name(emac, "FW_INF_PORT_DISABLED") +
+                       emac_get_stat_by_name(emac, "FW_INF_SAV") +
+                       emac_get_stat_by_name(emac, "FW_INF_SA_DL") +
+                       emac_get_stat_by_name(emac, "FW_INF_PORT_BLOCKED") +
+                       emac_get_stat_by_name(emac, "FW_INF_DROP_TAGGED") +
+                       emac_get_stat_by_name(emac, "FW_INF_DROP_PRIOTAGGED") +
+                       emac_get_stat_by_name(emac, "FW_INF_DROP_NOTAG") +
+                       emac_get_stat_by_name(emac, "FW_INF_DROP_NOTMEMBER");
+       stats->tx_dropped +=
+                       emac_get_stat_by_name(emac, "FW_RTU_PKT_DROP") +
+                       emac_get_stat_by_name(emac, "FW_TX_DROPPED_PACKET") +
+                       emac_get_stat_by_name(emac, "FW_TX_TS_DROPPED_PACKET") +
+                       emac_get_stat_by_name(emac, "FW_TX_JUMBO_FRM_CUTOFF");
 }
 EXPORT_SYMBOL_GPL(icssg_ndo_get_stats64);