This is a note to let you know that I've just added the patch titled
net: cadence: macb: Synchronize stats calculations
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-cadence-macb-synchronize-stats-calculations.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f7ad44c493cae50940e4a7dd9ac2a5cd26d5631d
Author: Sean Anderson <sean.anderson@xxxxxxxxx>
Date: Thu Feb 20 11:29:50 2025 -0500
net: cadence: macb: Synchronize stats calculations
[ 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@xxxxxxxxx>
Link: https://patch.msgid.link/20250220162950.95941-1-sean.anderson@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index 5de47f6fde5ab..7ce391209cdd1 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -1191,6 +1191,8 @@ 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 c3a8f6fc05aed..0f18837def3c8 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -1702,10 +1702,12 @@ 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));
@@ -2748,6 +2750,7 @@ 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 +
@@ -2777,6 +2780,7 @@ 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;
}
@@ -2784,12 +2788,13 @@ 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)
@@ -2839,6 +2844,7 @@ 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 */
@@ -2872,6 +2878,7 @@ 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;
}
@@ -4564,6 +4571,7 @@ static int macb_probe(struct platform_device *pdev)
device_set_wakeup_capable(&pdev->dev, bp->wol & MACB_WOL_HAS_MAGIC_PACKET);
spin_lock_init(&bp->lock);
+ spin_lock_init(&bp->stats_lock);
/* setup capabilities */
macb_configure_caps(bp, macb_config);
