Re: [PATCH net-next v2 04/11] net: ethtool: add netif_get_link_ksettings() for correct ops-locked use
From: Maxime Chevallier <maxime.chevallier@bootlin.com>
Date: 2026-06-03 06:40:17
Also in:
linux-leds
Hi Jakub On 6/3/26 03:28, Jakub Kicinski wrote:
__ethtool_get_link_ksettings() is exported and called from sysfs
and many drivers. It invokes ethtool_ops->get_link_ksettings
so by our own docs it should be holding netdev lock for ops locked
devices. Looks like commit 2bcf4772e45a ("net: ethtool:
try to protect all callback with netdev instance lock")
missed adding the ops lock here.
There's a number of callers we need to fix up so let's add the
netif_get_link_ksettings() helper first, without any actual
locking changes (this commit is a nop).
Not treating this as a fix because I don't think any driver cares
at this point, but if we want to remove the rtnl_lock protection
this will become critical.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com> Maxime
quoted hunk ↗ jump to hunk
--- v2: - split into multiple patches --- include/linux/ethtool.h | 2 ++ net/ethtool/ioctl.c | 17 ++++++++++++++--- net/ethtool/linkinfo.c | 4 ++-- net/ethtool/linkmodes.c | 4 ++-- 4 files changed, 20 insertions(+), 7 deletions(-)diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h index 1cb0740ba331..f51346a6a686 100644 --- a/include/linux/ethtool.h +++ b/include/linux/ethtool.h@@ -325,6 +325,8 @@ struct ethtool_link_ksettings { extern int __ethtool_get_link_ksettings(struct net_device *dev, struct ethtool_link_ksettings *link_ksettings); +int netif_get_link_ksettings(struct net_device *dev, + struct ethtool_link_ksettings *link_ksettings); struct ethtool_keee { __ETHTOOL_DECLARE_LINK_MODE_MASK(supported);diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c index bd97f9b9bf18..49da873b673d 100644 --- a/net/ethtool/ioctl.c +++ b/net/ethtool/ioctl.c@@ -436,10 +436,10 @@ struct ethtool_link_usettings { }; /* Internal kernel helper to query a device ethtool_link_settings. */ -int __ethtool_get_link_ksettings(struct net_device *dev, - struct ethtool_link_ksettings *link_ksettings) +int netif_get_link_ksettings(struct net_device *dev, + struct ethtool_link_ksettings *link_ksettings) { - ASSERT_RTNL(); + /* once callers fixed - assert ops locked */ if (!dev->ethtool_ops->get_link_ksettings) return -EOPNOTSUPP;@@ -450,6 +450,17 @@ int __ethtool_get_link_ksettings(struct net_device *dev, memset(link_ksettings, 0, sizeof(*link_ksettings)); return dev->ethtool_ops->get_link_ksettings(dev, link_ksettings); } +EXPORT_SYMBOL(netif_get_link_ksettings); + +/* Convenience helper for callers that hold only rtnl_lock(). */ +int __ethtool_get_link_ksettings(struct net_device *dev, + struct ethtool_link_ksettings *link_ksettings) +{ + ASSERT_RTNL(); + + /* once callers fixed - take the ops lock around this call */ + return netif_get_link_ksettings(dev, link_ksettings); +} EXPORT_SYMBOL(__ethtool_get_link_ksettings); /* convert ethtool_link_usettings in user space to a kernel internaldiff --git a/net/ethtool/linkinfo.c b/net/ethtool/linkinfo.c index 244ff92e2ff9..d5b3dbc53c5f 100644 --- a/net/ethtool/linkinfo.c +++ b/net/ethtool/linkinfo.c@@ -34,7 +34,7 @@ static int linkinfo_prepare_data(const struct ethnl_req_info *req_base, ret = ethnl_ops_begin(dev); if (ret < 0) return ret; - ret = __ethtool_get_link_ksettings(dev, &data->ksettings); + ret = netif_get_link_ksettings(dev, &data->ksettings); if (ret < 0) GENL_SET_ERR_MSG(info, "failed to retrieve link settings"); ethnl_ops_complete(dev);@@ -104,7 +104,7 @@ ethnl_set_linkinfo(struct ethnl_req_info *req_info, struct genl_info *info) bool mod = false; int ret; - ret = __ethtool_get_link_ksettings(dev, &ksettings); + ret = netif_get_link_ksettings(dev, &ksettings); if (ret < 0) { GENL_SET_ERR_MSG(info, "failed to retrieve link settings"); return ret;diff --git a/net/ethtool/linkmodes.c b/net/ethtool/linkmodes.c index 30d703531652..a6d32f0d9fcc 100644 --- a/net/ethtool/linkmodes.c +++ b/net/ethtool/linkmodes.c@@ -39,7 +39,7 @@ static int linkmodes_prepare_data(const struct ethnl_req_info *req_base, if (ret < 0) return ret; - ret = __ethtool_get_link_ksettings(dev, &data->ksettings); + ret = netif_get_link_ksettings(dev, &data->ksettings); if (ret < 0) { GENL_SET_ERR_MSG(info, "failed to retrieve link settings"); goto out;@@ -324,7 +324,7 @@ ethnl_set_linkmodes(struct ethnl_req_info *req_info, struct genl_info *info) bool mod = false; int ret; - ret = __ethtool_get_link_ksettings(dev, &ksettings); + ret = netif_get_link_ksettings(dev, &ksettings); if (ret < 0) { GENL_SET_ERR_MSG(info, "failed to retrieve link settings"); return ret;