From 2014beea7eb165c745706b13659a0f1d0a9a2a61 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 19 Jan 2021 12:25:18 -0800 Subject: [PATCH 1/4] net: move net_set_todo inside rollback_registered() Commit 93ee31f14f6f ("[NET]: Fix free_netdev on register_netdev failure.") moved net_set_todo() outside of rollback_registered() so that rollback_registered() can be used in the failure path of register_netdevice() but without risking a double free. Since commit cf124db566e6 ("net: Fix inconsistent teardown and release of private netdev state."), however, we have a better way of handling that condition, since destructors don't call free_netdev() directly. After the change in commit c269a24ce057 ("net: make free_netdev() more lenient with unregistering devices") we can now move net_set_todo() back. Reviewed-by: Edwin Peer Signed-off-by: Jakub Kicinski --- net/core/dev.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 07a0347c33fb0..9476edf702646 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9546,8 +9546,10 @@ static void rollback_registered_many(struct list_head *head) synchronize_net(); - list_for_each_entry(dev, head, unreg_list) + list_for_each_entry(dev, head, unreg_list) { dev_put(dev); + net_set_todo(dev); + } } static void rollback_registered(struct net_device *dev) @@ -10109,7 +10111,6 @@ int register_netdevice(struct net_device *dev) /* Expect explicit free_netdev() on failure */ dev->needs_free_netdev = false; rollback_registered(dev); - net_set_todo(dev); goto out; } /* @@ -10732,8 +10733,6 @@ void unregister_netdevice_queue(struct net_device *dev, struct list_head *head) list_move_tail(&dev->unreg_list, head); } else { rollback_registered(dev); - /* Finish processing unregister after unlock */ - net_set_todo(dev); } } EXPORT_SYMBOL(unregister_netdevice_queue); @@ -10747,12 +10746,8 @@ EXPORT_SYMBOL(unregister_netdevice_queue); */ void unregister_netdevice_many(struct list_head *head) { - struct net_device *dev; - if (!list_empty(head)) { rollback_registered_many(head); - list_for_each_entry(dev, head, unreg_list) - net_set_todo(dev); list_del(head); } } From 037e56bd965e1bc72c2fa9684ac25b56839a338e Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 19 Jan 2021 12:25:19 -0800 Subject: [PATCH 2/4] net: inline rollback_registered() rollback_registered() is a local helper, it's common for driver code to call unregister_netdevice_queue(dev, NULL) when they want to unregister netdevices under rtnl_lock. Inline rollback_registered() and adjust the only remaining caller. Reviewed-by: Edwin Peer Signed-off-by: Jakub Kicinski --- net/core/dev.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 9476edf702646..9a147142c477a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9552,15 +9552,6 @@ static void rollback_registered_many(struct list_head *head) } } -static void rollback_registered(struct net_device *dev) -{ - LIST_HEAD(single); - - list_add(&dev->unreg_list, &single); - rollback_registered_many(&single); - list_del(&single); -} - static netdev_features_t netdev_sync_upper_features(struct net_device *lower, struct net_device *upper, netdev_features_t features) { @@ -10110,7 +10101,7 @@ int register_netdevice(struct net_device *dev) if (ret) { /* Expect explicit free_netdev() on failure */ dev->needs_free_netdev = false; - rollback_registered(dev); + unregister_netdevice_queue(dev, NULL); goto out; } /* @@ -10732,7 +10723,11 @@ void unregister_netdevice_queue(struct net_device *dev, struct list_head *head) if (head) { list_move_tail(&dev->unreg_list, head); } else { - rollback_registered(dev); + LIST_HEAD(single); + + list_add(&dev->unreg_list, &single); + rollback_registered_many(&single); + list_del(&single); } } EXPORT_SYMBOL(unregister_netdevice_queue); From bcfe2f1a3818d9dca945b6aca4ae741cb1f75329 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 19 Jan 2021 12:25:20 -0800 Subject: [PATCH 3/4] net: move rollback_registered_many() Move rollback_registered_many() and add a temporary forward declaration to make merging the code into unregister_netdevice_many() easier to review. No functional changes. Reviewed-by: Edwin Peer Signed-off-by: Jakub Kicinski --- net/core/dev.c | 188 +++++++++++++++++++++++++------------------------ 1 file changed, 95 insertions(+), 93 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 9a147142c477a..1fb99ae8cc22e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9459,99 +9459,6 @@ static void net_set_todo(struct net_device *dev) dev_net(dev)->dev_unreg_count++; } -static void rollback_registered_many(struct list_head *head) -{ - struct net_device *dev, *tmp; - LIST_HEAD(close_head); - - BUG_ON(dev_boot_phase); - ASSERT_RTNL(); - - list_for_each_entry_safe(dev, tmp, head, unreg_list) { - /* Some devices call without registering - * for initialization unwind. Remove those - * devices and proceed with the remaining. - */ - if (dev->reg_state == NETREG_UNINITIALIZED) { - pr_debug("unregister_netdevice: device %s/%p never was registered\n", - dev->name, dev); - - WARN_ON(1); - list_del(&dev->unreg_list); - continue; - } - dev->dismantle = true; - BUG_ON(dev->reg_state != NETREG_REGISTERED); - } - - /* If device is running, close it first. */ - list_for_each_entry(dev, head, unreg_list) - list_add_tail(&dev->close_list, &close_head); - dev_close_many(&close_head, true); - - list_for_each_entry(dev, head, unreg_list) { - /* And unlink it from device chain. */ - unlist_netdevice(dev); - - dev->reg_state = NETREG_UNREGISTERING; - } - flush_all_backlogs(); - - synchronize_net(); - - list_for_each_entry(dev, head, unreg_list) { - struct sk_buff *skb = NULL; - - /* Shutdown queueing discipline. */ - dev_shutdown(dev); - - dev_xdp_uninstall(dev); - - /* Notify protocols, that we are about to destroy - * this device. They should clean all the things. - */ - call_netdevice_notifiers(NETDEV_UNREGISTER, dev); - - if (!dev->rtnl_link_ops || - dev->rtnl_link_state == RTNL_LINK_INITIALIZED) - skb = rtmsg_ifinfo_build_skb(RTM_DELLINK, dev, ~0U, 0, - GFP_KERNEL, NULL, 0); - - /* - * Flush the unicast and multicast chains - */ - dev_uc_flush(dev); - dev_mc_flush(dev); - - netdev_name_node_alt_flush(dev); - netdev_name_node_free(dev->name_node); - - if (dev->netdev_ops->ndo_uninit) - dev->netdev_ops->ndo_uninit(dev); - - if (skb) - rtmsg_ifinfo_send(skb, dev, GFP_KERNEL); - - /* Notifier chain MUST detach us all upper devices. */ - WARN_ON(netdev_has_any_upper_dev(dev)); - WARN_ON(netdev_has_any_lower_dev(dev)); - - /* Remove entries from kobject tree */ - netdev_unregister_kobject(dev); -#ifdef CONFIG_XPS - /* Remove XPS queueing entries */ - netif_reset_xps_queues_gt(dev, 0); -#endif - } - - synchronize_net(); - - list_for_each_entry(dev, head, unreg_list) { - dev_put(dev); - net_set_todo(dev); - } -} - static netdev_features_t netdev_sync_upper_features(struct net_device *lower, struct net_device *upper, netdev_features_t features) { @@ -10703,6 +10610,8 @@ void synchronize_net(void) } EXPORT_SYMBOL(synchronize_net); +static void rollback_registered_many(struct list_head *head); + /** * unregister_netdevice_queue - remove device from the kernel * @dev: device @@ -10748,6 +10657,99 @@ void unregister_netdevice_many(struct list_head *head) } EXPORT_SYMBOL(unregister_netdevice_many); +static void rollback_registered_many(struct list_head *head) +{ + struct net_device *dev, *tmp; + LIST_HEAD(close_head); + + BUG_ON(dev_boot_phase); + ASSERT_RTNL(); + + list_for_each_entry_safe(dev, tmp, head, unreg_list) { + /* Some devices call without registering + * for initialization unwind. Remove those + * devices and proceed with the remaining. + */ + if (dev->reg_state == NETREG_UNINITIALIZED) { + pr_debug("unregister_netdevice: device %s/%p never was registered\n", + dev->name, dev); + + WARN_ON(1); + list_del(&dev->unreg_list); + continue; + } + dev->dismantle = true; + BUG_ON(dev->reg_state != NETREG_REGISTERED); + } + + /* If device is running, close it first. */ + list_for_each_entry(dev, head, unreg_list) + list_add_tail(&dev->close_list, &close_head); + dev_close_many(&close_head, true); + + list_for_each_entry(dev, head, unreg_list) { + /* And unlink it from device chain. */ + unlist_netdevice(dev); + + dev->reg_state = NETREG_UNREGISTERING; + } + flush_all_backlogs(); + + synchronize_net(); + + list_for_each_entry(dev, head, unreg_list) { + struct sk_buff *skb = NULL; + + /* Shutdown queueing discipline. */ + dev_shutdown(dev); + + dev_xdp_uninstall(dev); + + /* Notify protocols, that we are about to destroy + * this device. They should clean all the things. + */ + call_netdevice_notifiers(NETDEV_UNREGISTER, dev); + + if (!dev->rtnl_link_ops || + dev->rtnl_link_state == RTNL_LINK_INITIALIZED) + skb = rtmsg_ifinfo_build_skb(RTM_DELLINK, dev, ~0U, 0, + GFP_KERNEL, NULL, 0); + + /* + * Flush the unicast and multicast chains + */ + dev_uc_flush(dev); + dev_mc_flush(dev); + + netdev_name_node_alt_flush(dev); + netdev_name_node_free(dev->name_node); + + if (dev->netdev_ops->ndo_uninit) + dev->netdev_ops->ndo_uninit(dev); + + if (skb) + rtmsg_ifinfo_send(skb, dev, GFP_KERNEL); + + /* Notifier chain MUST detach us all upper devices. */ + WARN_ON(netdev_has_any_upper_dev(dev)); + WARN_ON(netdev_has_any_lower_dev(dev)); + + /* Remove entries from kobject tree */ + netdev_unregister_kobject(dev); +#ifdef CONFIG_XPS + /* Remove XPS queueing entries */ + netif_reset_xps_queues_gt(dev, 0); +#endif + } + + synchronize_net(); + + list_for_each_entry(dev, head, unreg_list) { + dev_put(dev); + net_set_todo(dev); + } +} + /** * unregister_netdev - remove device from the kernel * @dev: device From 0cbe1e57a7b93517100b0eb63d8e445cfbeb630c Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 19 Jan 2021 12:25:21 -0800 Subject: [PATCH 4/4] net: inline rollback_registered_many() Similar to the change for rollback_registered() - rollback_registered_many() was a part of unregister_netdevice_many() minus the net_set_todo(), which is no longer needed. Functionally this patch moves the list_empty() check back after: BUG_ON(dev_boot_phase); ASSERT_RTNL(); but I can't find any reason why that would be an issue. Reviewed-by: Edwin Peer Signed-off-by: Jakub Kicinski --- net/core/dev.c | 22 ++++++++-------------- 1 file changed, 8 insertions(+), 14 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 1fb99ae8cc22e..00f970ba0248a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5709,7 +5709,7 @@ static void flush_all_backlogs(void) } /* we can have in flight packet[s] on the cpus we are not flushing, - * synchronize_net() in rollback_registered_many() will take care of + * synchronize_net() in unregister_netdevice_many() will take care of * them */ for_each_cpu(cpu, &flush_cpus) @@ -10610,8 +10610,6 @@ void synchronize_net(void) } EXPORT_SYMBOL(synchronize_net); -static void rollback_registered_many(struct list_head *head); - /** * unregister_netdevice_queue - remove device from the kernel * @dev: device @@ -10635,8 +10633,7 @@ void unregister_netdevice_queue(struct net_device *dev, struct list_head *head) LIST_HEAD(single); list_add(&dev->unreg_list, &single); - rollback_registered_many(&single); - list_del(&single); + unregister_netdevice_many(&single); } } EXPORT_SYMBOL(unregister_netdevice_queue); @@ -10649,15 +10646,6 @@ EXPORT_SYMBOL(unregister_netdevice_queue); * we force a list_del() to make sure stack wont be corrupted later. */ void unregister_netdevice_many(struct list_head *head) -{ - if (!list_empty(head)) { - rollback_registered_many(head); - list_del(head); - } -} -EXPORT_SYMBOL(unregister_netdevice_many); - -static void rollback_registered_many(struct list_head *head) { struct net_device *dev, *tmp; LIST_HEAD(close_head); @@ -10665,6 +10653,9 @@ static void rollback_registered_many(struct list_head *head) BUG_ON(dev_boot_phase); ASSERT_RTNL(); + if (list_empty(head)) + return; + list_for_each_entry_safe(dev, tmp, head, unreg_list) { /* Some devices call without registering * for initialization unwind. Remove those @@ -10748,7 +10739,10 @@ static void rollback_registered_many(struct list_head *head) dev_put(dev); net_set_todo(dev); } + + list_del(head); } +EXPORT_SYMBOL(unregister_netdevice_many); /** * unregister_netdev - remove device from the kernel