[PATCH 6.18 624/957] net: dsa: remove redundant netdev_lock_ops() from conduit ethtool ops
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2026-05-20 17:45:09
Also in:
stable
Subsystem:
networking [dsa], networking [general], the rest · Maintainers:
Andrew Lunn, Vladimir Oltean, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
6.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Stanislav Fomichev <redacted>
[ Upstream commit 0f99e0c3e19badaf3fdced0d3feba623e59eed41 ]
DSA replaces the conduit (master) device's ethtool_ops with its own
wrappers that aggregate stats from both the conduit and DSA switch
ports. Taking the lock again inside the DSA wrappers causes a deadlock.
Stumbled upon this when booting qemu with fbnic and CONFIG_NET_DSA_LOOP=y
(which looks like some kind of testing device that auto-populates the ports
of eth0). `ethtool -i` is enough to deadlock. This means we have basically zero
coverage for DSA stuff with real ops locked devs.
Remove the redundant netdev_lock_ops()/netdev_unlock_ops() calls from
the DSA conduit ethtool wrappers.
Fixes: 2bcf4772e45a ("net: ethtool: try to protect all callback with netdev instance lock")
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/20260414231035.1917035-1-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/dsa/conduit.c | 16 +---------------
1 file changed, 1 insertion(+), 15 deletions(-)
diff --git a/net/dsa/conduit.c b/net/dsa/conduit.c
index a1b044467bd6f..8398d72d7e4d3 100644
--- a/net/dsa/conduit.c
+++ b/net/dsa/conduit.c@@ -27,9 +27,7 @@ static int dsa_conduit_get_regs_len(struct net_device *dev) int len; if (ops && ops->get_regs_len) { - netdev_lock_ops(dev); len = ops->get_regs_len(dev); - netdev_unlock_ops(dev); if (len < 0) return len; ret += len;
@@ -60,15 +58,11 @@ static void dsa_conduit_get_regs(struct net_device *dev, int len; if (ops && ops->get_regs_len && ops->get_regs) { - netdev_lock_ops(dev); len = ops->get_regs_len(dev); - if (len < 0) { - netdev_unlock_ops(dev); + if (len < 0) return; - } regs->len = len; ops->get_regs(dev, regs, data); - netdev_unlock_ops(dev); data += regs->len; }
@@ -115,10 +109,8 @@ static void dsa_conduit_get_ethtool_stats(struct net_device *dev, int count, mcount = 0; if (ops && ops->get_sset_count && ops->get_ethtool_stats) { - netdev_lock_ops(dev); mcount = ops->get_sset_count(dev, ETH_SS_STATS); ops->get_ethtool_stats(dev, stats, data); - netdev_unlock_ops(dev); } list_for_each_entry(dp, &dst->ports, list) {
@@ -149,10 +141,8 @@ static void dsa_conduit_get_ethtool_phy_stats(struct net_device *dev, if (count >= 0) phy_ethtool_get_stats(dev->phydev, stats, data); } else if (ops && ops->get_sset_count && ops->get_ethtool_phy_stats) { - netdev_lock_ops(dev); count = ops->get_sset_count(dev, ETH_SS_PHY_STATS); ops->get_ethtool_phy_stats(dev, stats, data); - netdev_unlock_ops(dev); } if (count < 0)
@@ -176,13 +166,11 @@ static int dsa_conduit_get_sset_count(struct net_device *dev, int sset) struct dsa_switch_tree *dst = cpu_dp->dst; int count = 0; - netdev_lock_ops(dev); if (sset == ETH_SS_PHY_STATS && dev->phydev && (!ops || !ops->get_ethtool_phy_stats)) count = phy_ethtool_get_sset_count(dev->phydev); else if (ops && ops->get_sset_count) count = ops->get_sset_count(dev, sset); - netdev_unlock_ops(dev); if (count < 0) count = 0;
@@ -239,7 +227,6 @@ static void dsa_conduit_get_strings(struct net_device *dev, u32 stringset, struct dsa_switch_tree *dst = cpu_dp->dst; int count, mcount = 0; - netdev_lock_ops(dev); if (stringset == ETH_SS_PHY_STATS && dev->phydev && !ops->get_ethtool_phy_stats) { mcount = phy_ethtool_get_sset_count(dev->phydev);
@@ -253,7 +240,6 @@ static void dsa_conduit_get_strings(struct net_device *dev, u32 stringset, mcount = 0; ops->get_strings(dev, stringset, data); } - netdev_unlock_ops(dev); list_for_each_entry(dp, &dst->ports, list) { if (!dsa_port_is_dsa(dp) && !dsa_port_is_cpu(dp))
--
2.53.0