The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 18d8e67df184081bc6ce6220a2dd965cfd3d7e6b Mon Sep 17 00:00:00 2001 From: Vladimir Oltean vladimir.oltean@nxp.com Date: Tue, 16 Aug 2022 16:53:49 +0300 Subject: [PATCH] net: mscc: ocelot: fix race between ndo_get_stats64 and ocelot_check_stats_work
The 2 methods can run concurrently, and one will change the window of counters (SYS_STAT_CFG_STAT_VIEW) that the other sees. The fix is similar to what commit 7fbf6795d127 ("net: mscc: ocelot: fix mutex lock error during ethtool stats read") has done for ethtool -S.
Fixes: a556c76adc05 ("net: mscc: Add initial Ocelot switch support") Signed-off-by: Vladimir Oltean vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski kuba@kernel.org
diff --git a/drivers/net/ethernet/mscc/ocelot_net.c b/drivers/net/ethernet/mscc/ocelot_net.c index 9d8cea16245e..6b9d37138844 100644 --- a/drivers/net/ethernet/mscc/ocelot_net.c +++ b/drivers/net/ethernet/mscc/ocelot_net.c @@ -726,6 +726,8 @@ static void ocelot_get_stats64(struct net_device *dev, struct ocelot *ocelot = priv->port.ocelot; int port = priv->port.index;
+ spin_lock(&ocelot->stats_lock); + /* Configure the port to read the stats from */ ocelot_write(ocelot, SYS_STAT_CFG_STAT_VIEW(port), SYS_STAT_CFG); @@ -758,6 +760,8 @@ static void ocelot_get_stats64(struct net_device *dev, stats->tx_dropped = ocelot_read(ocelot, SYS_COUNT_TX_DROPS) + ocelot_read(ocelot, SYS_COUNT_TX_AGING); stats->collisions = ocelot_read(ocelot, SYS_COUNT_TX_COLLISION); + + spin_unlock(&ocelot->stats_lock); }
static int ocelot_port_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],