6.6-stable review patch. If anyone has any objections, please let me know.
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From: Sean Anderson sean.anderson@linux.dev
[ Upstream commit fa52f15c745ce55261b92873676f64f7348cfe82 ]
Stats calculations involve a RMW to add the stat update to the existing value. This is currently not protected by any synchronization mechanism, so data races are possible. Add a spinlock to protect the update. The reader side could be protected using u64_stats, but we would still need a spinlock for the update side anyway. And we always do an update immediately before reading the stats anyway.
Fixes: 89e5785fc8a6 ("[PATCH] Atmel MACB ethernet driver") Signed-off-by: Sean Anderson sean.anderson@linux.dev Link: https://patch.msgid.link/20250220162950.95941-1-sean.anderson@linux.dev Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/cadence/macb.h | 2 ++ drivers/net/ethernet/cadence/macb_main.c | 12 ++++++++++-- 2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h index 78c972bb1d962..9fb5a18e056d4 100644 --- a/drivers/net/ethernet/cadence/macb.h +++ b/drivers/net/ethernet/cadence/macb.h @@ -1270,6 +1270,8 @@ struct macb { struct clk *rx_clk; struct clk *tsu_clk; struct net_device *dev; + /* Protects hw_stats and ethtool_stats */ + spinlock_t stats_lock; union { struct macb_stats macb; struct gem_stats gem; diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index 8f61731e4554b..4325d0ace1f26 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -1992,10 +1992,12 @@ static irqreturn_t macb_interrupt(int irq, void *dev_id)
if (status & MACB_BIT(ISR_ROVR)) { /* We missed at least one packet */ + spin_lock(&bp->stats_lock); if (macb_is_gem(bp)) bp->hw_stats.gem.rx_overruns++; else bp->hw_stats.macb.rx_overruns++; + spin_unlock(&bp->stats_lock);
if (bp->caps & MACB_CAPS_ISR_CLEAR_ON_WRITE) queue_writel(queue, ISR, MACB_BIT(ISR_ROVR)); @@ -3084,6 +3086,7 @@ static struct net_device_stats *gem_get_stats(struct macb *bp) if (!netif_running(bp->dev)) return nstat;
+ spin_lock_irq(&bp->stats_lock); gem_update_stats(bp);
nstat->rx_errors = (hwstat->rx_frame_check_sequence_errors + @@ -3113,6 +3116,7 @@ static struct net_device_stats *gem_get_stats(struct macb *bp) nstat->tx_aborted_errors = hwstat->tx_excessive_collisions; nstat->tx_carrier_errors = hwstat->tx_carrier_sense_errors; nstat->tx_fifo_errors = hwstat->tx_underrun; + spin_unlock_irq(&bp->stats_lock);
return nstat; } @@ -3120,12 +3124,13 @@ static struct net_device_stats *gem_get_stats(struct macb *bp) static void gem_get_ethtool_stats(struct net_device *dev, struct ethtool_stats *stats, u64 *data) { - struct macb *bp; + struct macb *bp = netdev_priv(dev);
- bp = netdev_priv(dev); + spin_lock_irq(&bp->stats_lock); gem_update_stats(bp); memcpy(data, &bp->ethtool_stats, sizeof(u64) * (GEM_STATS_LEN + QUEUE_STATS_LEN * MACB_MAX_QUEUES)); + spin_unlock_irq(&bp->stats_lock); }
static int gem_get_sset_count(struct net_device *dev, int sset) @@ -3175,6 +3180,7 @@ static struct net_device_stats *macb_get_stats(struct net_device *dev) return gem_get_stats(bp);
/* read stats from hardware */ + spin_lock_irq(&bp->stats_lock); macb_update_stats(bp);
/* Convert HW stats into netdevice stats */ @@ -3208,6 +3214,7 @@ static struct net_device_stats *macb_get_stats(struct net_device *dev) nstat->tx_carrier_errors = hwstat->tx_carrier_errors; nstat->tx_fifo_errors = hwstat->tx_underruns; /* Don't know about heartbeat or window errors... */ + spin_unlock_irq(&bp->stats_lock);
return nstat; } @@ -5063,6 +5070,7 @@ static int macb_probe(struct platform_device *pdev) } } spin_lock_init(&bp->lock); + spin_lock_init(&bp->stats_lock);
/* setup capabilities */ macb_configure_caps(bp, macb_config);