From c269a24ce057abfc31130960e96ab197ef6ab196 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Wed, 6 Jan 2021 10:40:06 -0800 Subject: net: make free_netdev() more lenient with unregistering devices There are two flavors of handling netdev registration: - ones called without holding rtnl_lock: register_netdev() and unregister_netdev(); and - those called with rtnl_lock held: register_netdevice() and unregister_netdevice(). While the semantics of the former are pretty clear, the same can't be said about the latter. The netdev_todo mechanism is utilized to perform some of the device unregistering tasks and it hooks into rtnl_unlock() so the locked variants can't actually finish the work. In general free_netdev() does not mix well with locked calls. Most drivers operating under rtnl_lock set dev->needs_free_netdev to true and expect core to make the free_netdev() call some time later. The part where this becomes most problematic is error paths. There is no way to unwind the state cleanly after a call to register_netdevice(), since unreg can't be performed fully without dropping locks. Make free_netdev() more lenient, and defer the freeing if device is being unregistered. This allows error paths to simply call free_netdev() both after register_netdevice() failed, and after a call to unregister_netdevice() but before dropping rtnl_lock. Simplify the error paths which are currently doing gymnastics around free_netdev() handling. Signed-off-by: Jakub Kicinski --- net/core/dev.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index 8fa739259041..adde93cbca9f 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -10631,6 +10631,17 @@ void free_netdev(struct net_device *dev) struct napi_struct *p, *n; might_sleep(); + + /* When called immediately after register_netdevice() failed the unwind + * handling may still be dismantling the device. Handle that case by + * deferring the free. + */ + if (dev->reg_state == NETREG_UNREGISTERING) { + ASSERT_RTNL(); + dev->needs_free_netdev = true; + return; + } + netif_free_tx_queues(dev); netif_free_rx_queues(dev); -- cgit From 766b0515d5bec4b780750773ed3009b148df8c0a Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Wed, 6 Jan 2021 10:40:07 -0800 Subject: net: make sure devices go through netdev_wait_all_refs If register_netdevice() fails at the very last stage - the notifier call - some subsystems may have already seen it and grabbed a reference. struct net_device can't be freed right away without calling netdev_wait_all_refs(). Now that we have a clean interface in form of dev->needs_free_netdev and lenient free_netdev() we can undo what commit 93ee31f14f6f ("[NET]: Fix free_netdev on register_netdev failure.") has done and complete the unregistration path by bringing the net_set_todo() call back. After registration fails user is still expected to explicitly free the net_device, so make sure ->needs_free_netdev is cleared, otherwise rolling back the registration will cause the old double free for callers who release rtnl_lock before the free. This also solves the problem of priv_destructor not being called on notifier error. net_set_todo() will be moved back into unregister_netdevice_queue() in a follow up. Reported-by: Hulk Robot Reported-by: Yang Yingliang Signed-off-by: Jakub Kicinski --- net/core/dev.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index adde93cbca9f..0071a11a6dc3 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -10077,17 +10077,11 @@ int register_netdevice(struct net_device *dev) ret = call_netdevice_notifiers(NETDEV_REGISTER, dev); ret = notifier_to_errno(ret); if (ret) { + /* Expect explicit free_netdev() on failure */ + dev->needs_free_netdev = false; rollback_registered(dev); - rcu_barrier(); - - dev->reg_state = NETREG_UNREGISTERED; - /* We should put the kobject that hold in - * netdev_unregister_kobject(), otherwise - * the net device cannot be freed when - * driver calls free_netdev(), because the - * kobject is being hold. - */ - kobject_put(&dev->dev.kobj); + net_set_todo(dev); + goto out; } /* * Prevent userspace races by waiting until the network -- cgit From 25537d71e2d007faf42a244a75e5a2bb7c356234 Mon Sep 17 00:00:00 2001 From: Tariq Toukan Date: Thu, 14 Jan 2021 17:12:15 +0200 Subject: net: Allow NETIF_F_HW_TLS_TX if IP_CSUM && IPV6_CSUM Cited patch below blocked the TLS TX device offload unless HW_CSUM is set. This broke devices that use IP_CSUM && IP6_CSUM. Here we fix it. Note that the single HW_TLS_TX feature flag indicates support for both IPv4/6, hence it should still be disabled in case only one of (IP_CSUM | IPV6_CSUM) is set. Fixes: ae0b04b238e2 ("net: Disable NETIF_F_HW_TLS_TX when HW_CSUM is disabled") Signed-off-by: Tariq Toukan Reported-by: Rohit Maheshwari Reviewed-by: Maxim Mikityanskiy Link: https://lore.kernel.org/r/20210114151215.7061-1-tariqt@nvidia.com Signed-off-by: Jakub Kicinski --- net/core/dev.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index 0071a11a6dc3..c360bb5367e2 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9661,9 +9661,15 @@ static netdev_features_t netdev_fix_features(struct net_device *dev, } } - if ((features & NETIF_F_HW_TLS_TX) && !(features & NETIF_F_HW_CSUM)) { - netdev_dbg(dev, "Dropping TLS TX HW offload feature since no CSUM feature.\n"); - features &= ~NETIF_F_HW_TLS_TX; + if (features & NETIF_F_HW_TLS_TX) { + bool ip_csum = (features & (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM)) == + (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM); + bool hw_csum = features & NETIF_F_HW_CSUM; + + if (!ip_csum && !hw_csum) { + netdev_dbg(dev, "Dropping TLS TX HW offload feature since no CSUM feature.\n"); + features &= ~NETIF_F_HW_TLS_TX; + } } return features; -- cgit From a3eb4e9d4c9218476d05c52dfd2be3d6fdce6b91 Mon Sep 17 00:00:00 2001 From: Tariq Toukan Date: Sun, 17 Jan 2021 17:15:38 +0200 Subject: net: Disable NETIF_F_HW_TLS_RX when RXCSUM is disabled With NETIF_F_HW_TLS_RX packets are decrypted in HW. This cannot be logically done when RXCSUM offload is off. Fixes: 14136564c8ee ("net: Add TLS RX offload feature") Signed-off-by: Tariq Toukan Reviewed-by: Boris Pismenny Link: https://lore.kernel.org/r/20210117151538.9411-1-tariqt@nvidia.com Signed-off-by: Jakub Kicinski --- net/core/dev.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index c360bb5367e2..a979b86dbacd 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9672,6 +9672,11 @@ static netdev_features_t netdev_fix_features(struct net_device *dev, } } + if ((features & NETIF_F_HW_TLS_RX) && !(features & NETIF_F_RXCSUM)) { + netdev_dbg(dev, "Dropping TLS RX HW offload feature since no RXCSUM feature.\n"); + features &= ~NETIF_F_HW_TLS_RX; + } + return features; } -- cgit