* [PATCH net] net: ethtool: keep rtnl_lock for ops using ethtool_op_get_link()
@ 2026-06-24 19:04 Jakub Kicinski
0 siblings, 0 replies; only message in thread
From: Jakub Kicinski @ 2026-06-24 19:04 UTC (permalink / raw)
To: davem
Cc: netdev, edumazet, pabeni, andrew+netdev, horms, Jakub Kicinski,
Breno Leitao, joshwash, hramamurthy, anthony.l.nguyen,
przemyslaw.kitszel, saeedm, tariqt, mbloch, leon, alexanderduyck,
kernel-team, kys, haiyangz, wei.liu, decui, longli, jordanrhee,
jacob.e.keller, nktgrg, debarghyak, mohsin.bashr, ernis, sdf, gal,
linux-rdma, linux-hyperv
Breno reports following splats on mlx5:
RTNL: assertion failed at net/core/dev.c (2241)
WARNING: net/core/dev.c:2241 at netif_state_change+0xed/0x130, CPU#5: ethtool/1335
RIP: 0010:netif_state_change+0xf9/0x130
Call Trace:
<TASK>
__linkwatch_sync_dev+0xea/0x120
ethtool_op_get_link+0xe/0x20
__ethtool_get_link+0x26/0x40
linkstate_prepare_data+0x51/0x200
ethnl_default_doit+0x213/0x470
genl_family_rcv_msg_doit+0xdd/0x110
Looks like I missed ethtool_op_get_link() trying to sync linkwatch,
which needs rtnl_lock. Not all drivers do this - bnxt doesn't,
it just returns the link state, so add an opt-in bit.
Reported-by: Breno Leitao <leitao@debian.org>
Fixes: 45079e00133e ("net: ethtool: optionally skip rtnl_lock on Netlink path for GET ops")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
CC: joshwash@google.com
CC: hramamurthy@google.com
CC: anthony.l.nguyen@intel.com
CC: przemyslaw.kitszel@intel.com
CC: saeedm@nvidia.com
CC: tariqt@nvidia.com
CC: mbloch@nvidia.com
CC: leon@kernel.org
CC: alexanderduyck@fb.com
CC: kernel-team@meta.com
CC: kys@microsoft.com
CC: haiyangz@microsoft.com
CC: wei.liu@kernel.org
CC: decui@microsoft.com
CC: longli@microsoft.com
CC: jordanrhee@google.com
CC: jacob.e.keller@intel.com
CC: nktgrg@google.com
CC: debarghyak@google.com
CC: leitao@debian.org
CC: mohsin.bashr@gmail.com
CC: ernis@linux.microsoft.com
CC: sdf@fomichev.me
CC: gal@nvidia.com
CC: linux-rdma@vger.kernel.org
CC: linux-hyperv@vger.kernel.org
---
include/linux/ethtool.h | 2 ++
net/ethtool/common.h | 4 ++++
drivers/net/ethernet/google/gve/gve_ethtool.c | 3 ++-
drivers/net/ethernet/intel/iavf/iavf_ethtool.c | 1 +
drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c | 3 ++-
drivers/net/ethernet/mellanox/mlx5/core/en_rep.c | 3 ++-
drivers/net/ethernet/mellanox/mlx5/core/ipoib/ethtool.c | 4 +++-
drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c | 3 ++-
drivers/net/ethernet/microsoft/mana/mana_ethtool.c | 3 ++-
9 files changed, 20 insertions(+), 6 deletions(-)
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 1b834e2a522e..5d491a98265e 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -942,6 +942,7 @@ struct kernel_ethtool_ts_info {
#define ETHTOOL_OP_NEEDS_RTNL_GPAUSEPARAM BIT(5)
#define ETHTOOL_OP_NEEDS_RTNL_SPAUSEPARAM BIT(6)
#define ETHTOOL_OP_NEEDS_RTNL_RSS BIT(7)
+#define ETHTOOL_OP_NEEDS_RTNL_GLINK BIT(8)
/**
* struct ethtool_ops - optional netdev operations
@@ -978,6 +979,7 @@ struct kernel_ethtool_ts_info {
* - phylink helpers (note that phydev is currently unsupported!)
* - netdev_update_features()
* - netif_set_real_num_tx_queues()
+ * - ethtool_op_get_link() (syncs link watch under rtnl_lock)
*
* @get_drvinfo: Report driver/device information. Modern drivers no
* longer have to implement this callback. Most fields are
diff --git a/net/ethtool/common.h b/net/ethtool/common.h
index 2b3847f00801..4e5356e26f40 100644
--- a/net/ethtool/common.h
+++ b/net/ethtool/common.h
@@ -113,6 +113,8 @@ ethtool_nl_msg_needs_rtnl(const struct net_device *dev, u8 cmd)
return ops->op_needs_rtnl & ETHTOOL_OP_NEEDS_RTNL_SPAUSEPARAM;
case ETHTOOL_MSG_RSS_SET:
return ops->op_needs_rtnl & ETHTOOL_OP_NEEDS_RTNL_RSS;
+ case ETHTOOL_MSG_LINKSTATE_GET:
+ return ops->op_needs_rtnl & ETHTOOL_OP_NEEDS_RTNL_GLINK;
case ETHTOOL_MSG_TSCONFIG_GET:
case ETHTOOL_MSG_TSCONFIG_SET:
/* tsconfig calls ndos (ndo_hwtstamp_set/get), not ethtool ops.
@@ -159,6 +161,8 @@ ethtool_ioctl_needs_rtnl(const struct net_device *dev, u32 ethcmd)
case ETHTOOL_SRXFH:
case ETHTOOL_SRXFHINDIR:
return ops->op_needs_rtnl & ETHTOOL_OP_NEEDS_RTNL_RSS;
+ case ETHTOOL_GLINK:
+ return ops->op_needs_rtnl & ETHTOOL_OP_NEEDS_RTNL_GLINK;
}
return false;
}
diff --git a/drivers/net/ethernet/google/gve/gve_ethtool.c b/drivers/net/ethernet/google/gve/gve_ethtool.c
index 7cc22916852f..8199738ba979 100644
--- a/drivers/net/ethernet/google/gve/gve_ethtool.c
+++ b/drivers/net/ethernet/google/gve/gve_ethtool.c
@@ -984,7 +984,8 @@ const struct ethtool_ops gve_ethtool_ops = {
.supported_ring_params = ETHTOOL_RING_USE_TCP_DATA_SPLIT |
ETHTOOL_RING_USE_RX_BUF_LEN,
.op_needs_rtnl = ETHTOOL_OP_NEEDS_RTNL_SCHANNELS |
- ETHTOOL_OP_NEEDS_RTNL_SRINGPARAM,
+ ETHTOOL_OP_NEEDS_RTNL_SRINGPARAM |
+ ETHTOOL_OP_NEEDS_RTNL_GLINK,
.get_drvinfo = gve_get_drvinfo,
.get_strings = gve_get_strings,
.get_sset_count = gve_get_sset_count,
diff --git a/drivers/net/ethernet/intel/iavf/iavf_ethtool.c b/drivers/net/ethernet/intel/iavf/iavf_ethtool.c
index a615d599b88e..e7cf12eaa268 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_ethtool.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_ethtool.c
@@ -1855,6 +1855,7 @@ static const struct ethtool_ops iavf_ethtool_ops = {
.supported_coalesce_params = ETHTOOL_COALESCE_USECS |
ETHTOOL_COALESCE_USE_ADAPTIVE,
.supported_input_xfrm = RXH_XFRM_SYM_XOR,
+ .op_needs_rtnl = ETHTOOL_OP_NEEDS_RTNL_GLINK,
.get_drvinfo = iavf_get_drvinfo,
.get_link = ethtool_op_get_link,
.get_ringparam = iavf_get_ringparam,
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
index 2f5b626ba33f..112926d07634 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
@@ -2721,7 +2721,8 @@ const struct ethtool_ops mlx5e_ethtool_ops = {
.rxfh_max_num_contexts = MLX5E_MAX_NUM_RSS,
.op_needs_rtnl = ETHTOOL_OP_NEEDS_RTNL_SCHANNELS |
ETHTOOL_OP_NEEDS_RTNL_SRINGPARAM |
- ETHTOOL_OP_NEEDS_RTNL_SPFLAGS,
+ ETHTOOL_OP_NEEDS_RTNL_SPFLAGS |
+ ETHTOOL_OP_NEEDS_RTNL_GLINK,
.supported_coalesce_params = ETHTOOL_COALESCE_USECS |
ETHTOOL_COALESCE_MAX_FRAMES |
ETHTOOL_COALESCE_USE_ADAPTIVE |
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
index 1a8a19f980d3..c8b76d301c92 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
@@ -419,7 +419,8 @@ static const struct ethtool_ops mlx5e_rep_ethtool_ops = {
ETHTOOL_COALESCE_MAX_FRAMES |
ETHTOOL_COALESCE_USE_ADAPTIVE,
.op_needs_rtnl = ETHTOOL_OP_NEEDS_RTNL_SCHANNELS |
- ETHTOOL_OP_NEEDS_RTNL_SRINGPARAM,
+ ETHTOOL_OP_NEEDS_RTNL_SRINGPARAM |
+ ETHTOOL_OP_NEEDS_RTNL_GLINK,
.get_drvinfo = mlx5e_rep_get_drvinfo,
.get_link = ethtool_op_get_link,
.get_strings = mlx5e_rep_get_strings,
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/ipoib/ethtool.c b/drivers/net/ethernet/mellanox/mlx5/core/ipoib/ethtool.c
index 9b3b32408c64..01ddc3def9ac 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/ipoib/ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/ipoib/ethtool.c
@@ -286,7 +286,8 @@ const struct ethtool_ops mlx5i_ethtool_ops = {
ETHTOOL_COALESCE_MAX_FRAMES |
ETHTOOL_COALESCE_USE_ADAPTIVE,
.op_needs_rtnl = ETHTOOL_OP_NEEDS_RTNL_SCHANNELS |
- ETHTOOL_OP_NEEDS_RTNL_SRINGPARAM,
+ ETHTOOL_OP_NEEDS_RTNL_SRINGPARAM |
+ ETHTOOL_OP_NEEDS_RTNL_GLINK,
.get_drvinfo = mlx5i_get_drvinfo,
.get_strings = mlx5i_get_strings,
.get_sset_count = mlx5i_get_sset_count,
@@ -309,6 +310,7 @@ const struct ethtool_ops mlx5i_ethtool_ops = {
};
const struct ethtool_ops mlx5i_pkey_ethtool_ops = {
+ .op_needs_rtnl = ETHTOOL_OP_NEEDS_RTNL_GLINK,
.get_drvinfo = mlx5i_get_drvinfo,
.get_link = ethtool_op_get_link,
.get_ts_info = mlx5i_get_ts_info,
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
index cb34fc166ef9..0e47088ec44b 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
@@ -2024,7 +2024,8 @@ static const struct ethtool_ops fbnic_ethtool_ops = {
ETHTOOL_OP_NEEDS_RTNL_GPAUSEPARAM |
ETHTOOL_OP_NEEDS_RTNL_SPAUSEPARAM |
ETHTOOL_OP_NEEDS_RTNL_SCHANNELS |
- ETHTOOL_OP_NEEDS_RTNL_SRINGPARAM,
+ ETHTOOL_OP_NEEDS_RTNL_SRINGPARAM |
+ ETHTOOL_OP_NEEDS_RTNL_GLINK,
.get_drvinfo = fbnic_get_drvinfo,
.get_regs_len = fbnic_get_regs_len,
.get_regs = fbnic_get_regs,
diff --git a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
index 94e658d07a27..881df597d7f9 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
@@ -597,7 +597,8 @@ static int mana_get_link_ksettings(struct net_device *ndev,
const struct ethtool_ops mana_ethtool_ops = {
.supported_coalesce_params = ETHTOOL_COALESCE_RX_CQE_FRAMES,
.op_needs_rtnl = ETHTOOL_OP_NEEDS_RTNL_SCHANNELS |
- ETHTOOL_OP_NEEDS_RTNL_SRINGPARAM,
+ ETHTOOL_OP_NEEDS_RTNL_SRINGPARAM |
+ ETHTOOL_OP_NEEDS_RTNL_GLINK,
.get_ethtool_stats = mana_get_ethtool_stats,
.get_sset_count = mana_get_sset_count,
.get_strings = mana_get_strings,
--
2.54.0
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