From: Alexander Duyck An offline self test that brings the interface down and back up with netif_close() / netif_open() requires rtnl_lock for both. Since the ethtool IOCTL path became rtnl-optional for ops-locked drivers, the ETHTOOL_TEST ioctl runs holding only the netdev instance lock, so on an ops-locked driver the self test now tears the device down without rtnl_lock. With lockdep this reproduces deterministically on every offline self test on such a driver; note the sole lock held is the instance lock, not rtnl: WARNING: suspicious RCU usage net/core/netpoll.c:207 suspicious rcu_dereference_protected() usage! 1 lock held by ethtool/107: #0: (&dev->lock){+.+.}, at: dev_ethtool Call Trace: netpoll_poll_disable __dev_close_many netif_close_many netif_close fbnic_self_test dev_ethtool_locked dev_ethtool dev_ioctl sock_ioctl __x64_sys_ioctl Without lockdep the same condition trips ASSERT_RTNL() in __dev_close_many() / __dev_open(); that check only samples the global rtnl state, so it can be masked by a concurrent rtnl holder, but the device is still being reconfigured without the lock it requires. The ethtool self_test is a legacy ioctl-only command, so an ETHTOOL_TEST case is only needed on the ioctl path. Add an opt-in bit for drivers whose self test needs rtnl_lock and set it on the ops-locked drivers whose offline self test tears the interface down and up: - fbnic (ops-locked via queue_mgmt_ops): fbnic_self_test() offline path uses netif_close() / netif_open(). - bnxt (ops-locked via queue_mgmt_ops): bnxt_self_test() offline path goes through bnxt_close_nic() / bnxt_half_open_nic() / bnxt_half_close_nic() / bnxt_open_nic(), which close and reopen the device. Fixes: f994752b1127 ("net: ethtool: optionally skip rtnl_lock on IOCTL path") Signed-off-by: Alexander Duyck --- drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c | 3 ++- drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c | 3 ++- include/linux/ethtool.h | 2 ++ net/ethtool/common.h | 2 ++ 4 files changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c index 62bc9cae613c..622e89587e5d 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c @@ -5733,7 +5733,8 @@ const struct ethtool_ops bnxt_ethtool_ops = { .op_needs_rtnl = ETHTOOL_OP_NEEDS_RTNL_SCHANNELS | ETHTOOL_OP_NEEDS_RTNL_SRINGPARAM | ETHTOOL_OP_NEEDS_RTNL_SCOALESCE | - ETHTOOL_OP_NEEDS_RTNL_RSS, + ETHTOOL_OP_NEEDS_RTNL_RSS | + ETHTOOL_OP_NEEDS_RTNL_TEST, .supported_coalesce_params = ETHTOOL_COALESCE_USECS | ETHTOOL_COALESCE_MAX_FRAMES | ETHTOOL_COALESCE_USECS_IRQ | diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c index 0e47088ec44b..423f179c9d47 100644 --- a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c +++ b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c @@ -2025,7 +2025,8 @@ static const struct ethtool_ops fbnic_ethtool_ops = { ETHTOOL_OP_NEEDS_RTNL_SPAUSEPARAM | ETHTOOL_OP_NEEDS_RTNL_SCHANNELS | ETHTOOL_OP_NEEDS_RTNL_SRINGPARAM | - ETHTOOL_OP_NEEDS_RTNL_GLINK, + ETHTOOL_OP_NEEDS_RTNL_GLINK | + ETHTOOL_OP_NEEDS_RTNL_TEST, .get_drvinfo = fbnic_get_drvinfo, .get_regs_len = fbnic_get_regs_len, .get_regs = fbnic_get_regs, diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h index 253600c0eccd..c4c9ce038611 100644 --- a/include/linux/ethtool.h +++ b/include/linux/ethtool.h @@ -944,6 +944,7 @@ struct kernel_ethtool_ts_info { #define ETHTOOL_OP_NEEDS_RTNL_SPAUSEPARAM BIT(6) #define ETHTOOL_OP_NEEDS_RTNL_RSS BIT(7) #define ETHTOOL_OP_NEEDS_RTNL_GLINK BIT(8) +#define ETHTOOL_OP_NEEDS_RTNL_TEST BIT(9) /** * struct ethtool_ops - optional netdev operations @@ -981,6 +982,7 @@ struct kernel_ethtool_ts_info { * - netdev_update_features() * - netif_set_real_num_tx_queues() * - ethtool_op_get_link() (syncs link watch under rtnl_lock) + * - netif_open() / netif_close() (used by @self_test) * * @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 4e5356e26f40..ae32e7fdb563 100644 --- a/net/ethtool/common.h +++ b/net/ethtool/common.h @@ -163,6 +163,8 @@ ethtool_ioctl_needs_rtnl(const struct net_device *dev, u32 ethcmd) return ops->op_needs_rtnl & ETHTOOL_OP_NEEDS_RTNL_RSS; case ETHTOOL_GLINK: return ops->op_needs_rtnl & ETHTOOL_OP_NEEDS_RTNL_GLINK; + case ETHTOOL_TEST: + return ops->op_needs_rtnl & ETHTOOL_OP_NEEDS_RTNL_TEST; } return false; }