From d2ccd0560d9648a98ae0c6534588144044cff0a0 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Tue, 1 Apr 2025 09:34:42 -0700 Subject: [PATCH 1/8] net: switch to netif_disable_lro in inetdev_init Cosmin reports the following deadlock: dump_stack_lvl+0x62/0x90 print_deadlock_bug+0x274/0x3b0 __lock_acquire+0x1229/0x2470 lock_acquire+0xb7/0x2b0 __mutex_lock+0xa6/0xd20 dev_disable_lro+0x20/0x80 inetdev_init+0x12f/0x1f0 inetdev_event+0x48b/0x870 notifier_call_chain+0x38/0xf0 netif_change_net_namespace+0x72e/0x9f0 do_setlink.isra.0+0xd5/0x1220 rtnl_newlink+0x7ea/0xb50 rtnetlink_rcv_msg+0x459/0x5e0 netlink_rcv_skb+0x54/0x100 netlink_unicast+0x193/0x270 netlink_sendmsg+0x204/0x450 Switch to netif_disable_lro which assumes the caller holds the instance lock. inetdev_init is called for blackhole device (which sw device and doesn't grab instance lock) and from REGISTER/UNREGISTER notifiers. We already hold the instance lock for REGISTER notifier during netns change and we'll soon hold the lock during other paths. Reviewed-by: Jakub Kicinski Reported-by: Cosmin Ratiu Fixes: ad7c7b2172c3 ("net: hold netdev instance lock during sysfs operations") Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20250401163452.622454-2-sdf@fomichev.me Signed-off-by: Jakub Kicinski --- net/ipv4/devinet.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index 754f60fb6e25..77e5705ac799 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -281,7 +281,7 @@ static struct in_device *inetdev_init(struct net_device *dev) if (!in_dev->arp_parms) goto out_kfree; if (IPV4_DEVCONF(in_dev->cnf, FORWARDING)) - dev_disable_lro(dev); + netif_disable_lro(dev); /* Reference in_dev->dev */ netdev_hold(dev, &in_dev->dev_tracker, GFP_KERNEL); /* Account for reference dev->ip_ptr (below) */ From 4c975fd700022c90e61a46326e3444e08317876e Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Tue, 1 Apr 2025 09:34:43 -0700 Subject: [PATCH 2/8] net: hold instance lock during NETDEV_REGISTER/UP Callers of inetdev_init can come from several places with inconsistent expectation about netdev instance lock. Grab instance lock during REGISTER (plus UP). Also solve the inconsistency with UNREGISTER where it was locked only during move netns path. WARNING: CPU: 10 PID: 1479 at ./include/net/netdev_lock.h:54 __netdev_update_features+0x65f/0xca0 __warn+0x81/0x180 __netdev_update_features+0x65f/0xca0 report_bug+0x156/0x180 handle_bug+0x4f/0x90 exc_invalid_op+0x13/0x60 asm_exc_invalid_op+0x16/0x20 __netdev_update_features+0x65f/0xca0 netif_disable_lro+0x30/0x1d0 inetdev_init+0x12f/0x1f0 inetdev_event+0x48b/0x870 notifier_call_chain+0x38/0xf0 register_netdevice+0x741/0x8b0 register_netdev+0x1f/0x40 mlx5e_probe+0x4e3/0x8e0 [mlx5_core] auxiliary_bus_probe+0x3f/0x90 really_probe+0xc3/0x3a0 __driver_probe_device+0x80/0x150 driver_probe_device+0x1f/0x90 __device_attach_driver+0x7d/0x100 bus_for_each_drv+0x80/0xd0 __device_attach+0xb4/0x1c0 bus_probe_device+0x91/0xa0 device_add+0x657/0x870 Reviewed-by: Jakub Kicinski Reported-by: Cosmin Ratiu Fixes: ad7c7b2172c3 ("net: hold netdev instance lock during sysfs operations") Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20250401163452.622454-3-sdf@fomichev.me Signed-off-by: Jakub Kicinski --- include/linux/netdevice.h | 2 +- net/core/dev.c | 12 +++++++++--- net/core/dev_api.c | 8 +------- net/core/rtnetlink.c | 8 ++++---- 4 files changed, 15 insertions(+), 15 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index fa79145518d1..cf3b6445817b 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -4192,7 +4192,7 @@ int dev_change_flags(struct net_device *dev, unsigned int flags, int netif_set_alias(struct net_device *dev, const char *alias, size_t len); int dev_set_alias(struct net_device *, const char *, size_t); int dev_get_alias(const struct net_device *, char *, size_t); -int netif_change_net_namespace(struct net_device *dev, struct net *net, +int __dev_change_net_namespace(struct net_device *dev, struct net *net, const char *pat, int new_ifindex, struct netlink_ext_ack *extack); int dev_change_net_namespace(struct net_device *dev, struct net *net, diff --git a/net/core/dev.c b/net/core/dev.c index 5d20ff226d5e..ce6612106e60 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1858,7 +1858,9 @@ static int call_netdevice_register_net_notifiers(struct notifier_block *nb, int err; for_each_netdev(net, dev) { + netdev_lock_ops(dev); err = call_netdevice_register_notifiers(nb, dev); + netdev_unlock_ops(dev); if (err) goto rollback; } @@ -11047,7 +11049,9 @@ int register_netdevice(struct net_device *dev) memcpy(dev->perm_addr, dev->dev_addr, dev->addr_len); /* Notify protocols, that a new device appeared. */ + netdev_lock_ops(dev); ret = call_netdevice_notifiers(NETDEV_REGISTER, dev); + netdev_unlock_ops(dev); ret = notifier_to_errno(ret); if (ret) { /* Expect explicit free_netdev() on failure */ @@ -12059,7 +12063,7 @@ void unregister_netdev(struct net_device *dev) } EXPORT_SYMBOL(unregister_netdev); -int netif_change_net_namespace(struct net_device *dev, struct net *net, +int __dev_change_net_namespace(struct net_device *dev, struct net *net, const char *pat, int new_ifindex, struct netlink_ext_ack *extack) { @@ -12144,11 +12148,12 @@ int netif_change_net_namespace(struct net_device *dev, struct net *net, * And now a mini version of register_netdevice unregister_netdevice. */ + netdev_lock_ops(dev); /* If device is running close it first. */ netif_close(dev); - /* And unlink it from device chain */ unlist_netdevice(dev); + netdev_unlock_ops(dev); synchronize_net(); @@ -12210,11 +12215,12 @@ int netif_change_net_namespace(struct net_device *dev, struct net *net, err = netdev_change_owner(dev, net_old, net); WARN_ON(err); + netdev_lock_ops(dev); /* Add the device back in the hashes */ list_netdevice(dev); - /* Notify protocols, that a new device appeared. */ call_netdevice_notifiers(NETDEV_REGISTER, dev); + netdev_unlock_ops(dev); /* * Prevent userspace races by waiting until the network diff --git a/net/core/dev_api.c b/net/core/dev_api.c index 8dbc60612100..90bafb0b1b8c 100644 --- a/net/core/dev_api.c +++ b/net/core/dev_api.c @@ -117,13 +117,7 @@ EXPORT_SYMBOL(dev_set_mac_address_user); int dev_change_net_namespace(struct net_device *dev, struct net *net, const char *pat) { - int ret; - - netdev_lock_ops(dev); - ret = netif_change_net_namespace(dev, net, pat, 0, NULL); - netdev_unlock_ops(dev); - - return ret; + return __dev_change_net_namespace(dev, net, pat, 0, NULL); } EXPORT_SYMBOL_GPL(dev_change_net_namespace); diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 334db17be37d..c23852835050 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3025,8 +3025,6 @@ static int do_setlink(const struct sk_buff *skb, struct net_device *dev, char ifname[IFNAMSIZ]; int err; - netdev_lock_ops(dev); - err = validate_linkmsg(dev, tb, extack); if (err < 0) goto errout; @@ -3042,14 +3040,16 @@ static int do_setlink(const struct sk_buff *skb, struct net_device *dev, new_ifindex = nla_get_s32_default(tb[IFLA_NEW_IFINDEX], 0); - err = netif_change_net_namespace(dev, tgt_net, pat, + err = __dev_change_net_namespace(dev, tgt_net, pat, new_ifindex, extack); if (err) - goto errout; + return err; status |= DO_SETLINK_MODIFIED; } + netdev_lock_ops(dev); + if (tb[IFLA_MAP]) { struct rtnl_link_ifmap *u_map; struct ifmap k_map; From 8965c160b8f7333df895321c8aa6bad4a7175f2b Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Tue, 1 Apr 2025 09:34:44 -0700 Subject: [PATCH 3/8] net: use netif_disable_lro in ipv6_add_dev ipv6_add_dev might call dev_disable_lro which unconditionally grabs instance lock, so it will deadlock during NETDEV_REGISTER. Switch to netif_disable_lro. Make sure all callers hold the instance lock as well. Cc: Cosmin Ratiu Fixes: ad7c7b2172c3 ("net: hold netdev instance lock during sysfs operations") Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20250401163452.622454-4-sdf@fomichev.me Signed-off-by: Jakub Kicinski --- include/net/ip.h | 16 ++++++++-------- net/core/dev.c | 1 + net/ipv6/addrconf.c | 15 +++++++++++++-- 3 files changed, 22 insertions(+), 10 deletions(-) diff --git a/include/net/ip.h b/include/net/ip.h index 8a48ade24620..47ed6d23853d 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -667,14 +667,6 @@ static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, memcpy(buf, &naddr, sizeof(naddr)); } -#if IS_MODULE(CONFIG_IPV6) -#define EXPORT_IPV6_MOD(X) EXPORT_SYMBOL(X) -#define EXPORT_IPV6_MOD_GPL(X) EXPORT_SYMBOL_GPL(X) -#else -#define EXPORT_IPV6_MOD(X) -#define EXPORT_IPV6_MOD_GPL(X) -#endif - #if IS_ENABLED(CONFIG_IPV6) #include #endif @@ -694,6 +686,14 @@ static __inline__ void inet_reset_saddr(struct sock *sk) #endif +#if IS_MODULE(CONFIG_IPV6) +#define EXPORT_IPV6_MOD(X) EXPORT_SYMBOL(X) +#define EXPORT_IPV6_MOD_GPL(X) EXPORT_SYMBOL_GPL(X) +#else +#define EXPORT_IPV6_MOD(X) +#define EXPORT_IPV6_MOD_GPL(X) +#endif + static inline unsigned int ipv4_addr_hash(__be32 ip) { return (__force unsigned int) ip; diff --git a/net/core/dev.c b/net/core/dev.c index ce6612106e60..0608605cfc24 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1771,6 +1771,7 @@ void netif_disable_lro(struct net_device *dev) netdev_unlock_ops(lower_dev); } } +EXPORT_IPV6_MOD(netif_disable_lro); /** * dev_disable_gro_hw - disable HW Generic Receive Offload on a device diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 54a8ea004da2..c3b908fccbc1 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -80,6 +80,7 @@ #include #include #include +#include #include #include #include @@ -377,6 +378,7 @@ static struct inet6_dev *ipv6_add_dev(struct net_device *dev) int err = -ENOMEM; ASSERT_RTNL(); + netdev_ops_assert_locked(dev); if (dev->mtu < IPV6_MIN_MTU && dev != blackhole_netdev) return ERR_PTR(-EINVAL); @@ -402,7 +404,7 @@ static struct inet6_dev *ipv6_add_dev(struct net_device *dev) return ERR_PTR(err); } if (ndev->cnf.forwarding) - dev_disable_lro(dev); + netif_disable_lro(dev); /* We refer to the device */ netdev_hold(dev, &ndev->dev_tracker, GFP_KERNEL); @@ -3152,10 +3154,12 @@ int addrconf_add_ifaddr(struct net *net, void __user *arg) rtnl_net_lock(net); dev = __dev_get_by_index(net, ireq.ifr6_ifindex); + netdev_lock_ops(dev); if (dev) err = inet6_addr_add(net, dev, &cfg, 0, 0, NULL); else err = -ENODEV; + netdev_unlock_ops(dev); rtnl_net_unlock(net); return err; } @@ -5026,9 +5030,10 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, if (!dev) { NL_SET_ERR_MSG_MOD(extack, "Unable to find the interface"); err = -ENODEV; - goto unlock; + goto unlock_rtnl; } + netdev_lock_ops(dev); idev = ipv6_find_idev(dev); if (IS_ERR(idev)) { err = PTR_ERR(idev); @@ -5065,6 +5070,8 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, in6_ifa_put(ifa); unlock: + netdev_unlock_ops(dev); +unlock_rtnl: rtnl_net_unlock(net); return err; @@ -6516,7 +6523,9 @@ static int addrconf_sysctl_addr_gen_mode(const struct ctl_table *ctl, int write, if (idev->cnf.addr_gen_mode != new_val) { WRITE_ONCE(idev->cnf.addr_gen_mode, new_val); + netdev_lock_ops(idev->dev); addrconf_init_auto_addrs(idev->dev); + netdev_unlock_ops(idev->dev); } } else if (&net->ipv6.devconf_all->addr_gen_mode == ctl->data) { struct net_device *dev; @@ -6528,7 +6537,9 @@ static int addrconf_sysctl_addr_gen_mode(const struct ctl_table *ctl, int write, idev->cnf.addr_gen_mode != new_val) { WRITE_ONCE(idev->cnf.addr_gen_mode, new_val); + netdev_lock_ops(idev->dev); addrconf_init_auto_addrs(idev->dev); + netdev_unlock_ops(idev->dev); } } } From b912d599d3d83ff9a2db58c17b5c76429a206db5 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Tue, 1 Apr 2025 09:34:45 -0700 Subject: [PATCH 4/8] net: rename rtnl_net_debug to lock_debug And make it selected by CONFIG_DEBUG_NET. Don't rename any of the structs/functions. Next patch will use rtnl_net_debug_event in netdevsim. Reviewed-by: Jakub Kicinski Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20250401163452.622454-5-sdf@fomichev.me Signed-off-by: Jakub Kicinski --- net/core/Makefile | 2 +- net/core/{rtnl_net_debug.c => lock_debug.c} | 0 2 files changed, 1 insertion(+), 1 deletion(-) rename net/core/{rtnl_net_debug.c => lock_debug.c} (100%) diff --git a/net/core/Makefile b/net/core/Makefile index a10c3bd96798..b2a76ce33932 100644 --- a/net/core/Makefile +++ b/net/core/Makefile @@ -45,5 +45,5 @@ obj-$(CONFIG_BPF_SYSCALL) += bpf_sk_storage.o obj-$(CONFIG_OF) += of_net.o obj-$(CONFIG_NET_TEST) += net_test.o obj-$(CONFIG_NET_DEVMEM) += devmem.o -obj-$(CONFIG_DEBUG_NET_SMALL_RTNL) += rtnl_net_debug.o +obj-$(CONFIG_DEBUG_NET) += lock_debug.o obj-$(CONFIG_FAIL_SKB_REALLOC) += skb_fault_injection.o diff --git a/net/core/rtnl_net_debug.c b/net/core/lock_debug.c similarity index 100% rename from net/core/rtnl_net_debug.c rename to net/core/lock_debug.c From 1901066aab7654f4a225ac29354a564d891d0c1a Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Tue, 1 Apr 2025 09:34:46 -0700 Subject: [PATCH 5/8] netdevsim: add dummy device notifiers In order to exercise and verify notifiers' locking assumptions, register dummy notifiers (via register_netdevice_notifier_dev_net). Share notifier event handler that enforces the assumptions with lock_debug.c (rename and export rtnl_net_debug_event as netdev_debug_event). Add ops lock asserts to netdev_debug_event. Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20250401163452.622454-6-sdf@fomichev.me Signed-off-by: Jakub Kicinski --- drivers/net/netdevsim/netdev.c | 13 +++++++++++++ drivers/net/netdevsim/netdevsim.h | 3 +++ include/net/netdev_lock.h | 3 +++ net/core/lock_debug.c | 14 +++++++++----- 4 files changed, 28 insertions(+), 5 deletions(-) diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c index b67af4651185..ddda0c1e7a6d 100644 --- a/drivers/net/netdevsim/netdev.c +++ b/drivers/net/netdevsim/netdev.c @@ -939,6 +939,7 @@ static int nsim_init_netdevsim(struct netdevsim *ns) ns->netdev->netdev_ops = &nsim_netdev_ops; ns->netdev->stat_ops = &nsim_stat_ops; ns->netdev->queue_mgmt_ops = &nsim_queue_mgmt_ops; + netdev_lockdep_set_classes(ns->netdev); err = nsim_udp_tunnels_info_create(ns->nsim_dev, ns->netdev); if (err) @@ -960,6 +961,14 @@ static int nsim_init_netdevsim(struct netdevsim *ns) if (err) goto err_ipsec_teardown; rtnl_unlock(); + + if (IS_ENABLED(CONFIG_DEBUG_NET)) { + ns->nb.notifier_call = netdev_debug_event; + if (register_netdevice_notifier_dev_net(ns->netdev, &ns->nb, + &ns->nn)) + ns->nb.notifier_call = NULL; + } + return 0; err_ipsec_teardown: @@ -1043,6 +1052,10 @@ void nsim_destroy(struct netdevsim *ns) debugfs_remove(ns->qr_dfs); debugfs_remove(ns->pp_dfs); + if (ns->nb.notifier_call) + unregister_netdevice_notifier_dev_net(ns->netdev, &ns->nb, + &ns->nn); + rtnl_lock(); peer = rtnl_dereference(ns->peer); if (peer) diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h index 665020d18f29..d04401f0bdf7 100644 --- a/drivers/net/netdevsim/netdevsim.h +++ b/drivers/net/netdevsim/netdevsim.h @@ -144,6 +144,9 @@ struct netdevsim { struct nsim_ethtool ethtool; struct netdevsim __rcu *peer; + + struct notifier_block nb; + struct netdev_net_notifier nn; }; struct netdevsim * diff --git a/include/net/netdev_lock.h b/include/net/netdev_lock.h index 1c0c9a94cc22..c316b551df8d 100644 --- a/include/net/netdev_lock.h +++ b/include/net/netdev_lock.h @@ -98,4 +98,7 @@ static inline int netdev_lock_cmp_fn(const struct lockdep_map *a, &qdisc_xmit_lock_key); \ } +int netdev_debug_event(struct notifier_block *nb, unsigned long event, + void *ptr); + #endif diff --git a/net/core/lock_debug.c b/net/core/lock_debug.c index f3272b09c255..b7f22dc92a6f 100644 --- a/net/core/lock_debug.c +++ b/net/core/lock_debug.c @@ -6,10 +6,11 @@ #include #include #include +#include #include -static int rtnl_net_debug_event(struct notifier_block *nb, - unsigned long event, void *ptr) +int netdev_debug_event(struct notifier_block *nb, unsigned long event, + void *ptr) { struct net_device *dev = netdev_notifier_info_to_dev(ptr); struct net *net = dev_net(dev); @@ -17,11 +18,13 @@ static int rtnl_net_debug_event(struct notifier_block *nb, /* Keep enum and don't add default to trigger -Werror=switch */ switch (cmd) { + case NETDEV_REGISTER: case NETDEV_UP: + netdev_ops_assert_locked(dev); + fallthrough; case NETDEV_DOWN: case NETDEV_REBOOT: case NETDEV_CHANGE: - case NETDEV_REGISTER: case NETDEV_UNREGISTER: case NETDEV_CHANGEMTU: case NETDEV_CHANGEADDR: @@ -66,6 +69,7 @@ static int rtnl_net_debug_event(struct notifier_block *nb, return NOTIFY_DONE; } +EXPORT_SYMBOL_NS_GPL(netdev_debug_event, "NETDEV_INTERNAL"); static int rtnl_net_debug_net_id; @@ -74,7 +78,7 @@ static int __net_init rtnl_net_debug_net_init(struct net *net) struct notifier_block *nb; nb = net_generic(net, rtnl_net_debug_net_id); - nb->notifier_call = rtnl_net_debug_event; + nb->notifier_call = netdev_debug_event; return register_netdevice_notifier_net(net, nb); } @@ -95,7 +99,7 @@ static struct pernet_operations rtnl_net_debug_net_ops __net_initdata = { }; static struct notifier_block rtnl_net_debug_block = { - .notifier_call = rtnl_net_debug_event, + .notifier_call = netdev_debug_event, }; static int __init rtnl_net_debug_init(void) From dbfc99495d960134bfe1a4f13849fb0d5373b42c Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Tue, 1 Apr 2025 09:34:47 -0700 Subject: [PATCH 6/8] net: dummy: request ops lock Even though dummy device doesn't really need an instance lock, a lot of selftests use dummy so it's useful to have extra expose to the instance lock on NIPA. Request the instance/ops locking. Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20250401163452.622454-7-sdf@fomichev.me Signed-off-by: Jakub Kicinski --- drivers/net/dummy.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c index a4938c6a5ebb..d6bdad4baadd 100644 --- a/drivers/net/dummy.c +++ b/drivers/net/dummy.c @@ -105,6 +105,7 @@ static void dummy_setup(struct net_device *dev) dev->netdev_ops = &dummy_netdev_ops; dev->ethtool_ops = &dummy_ethtool_ops; dev->needs_free_netdev = true; + dev->request_ops_lock = true; /* Fill in device structure with ethernet-generic values. */ dev->flags |= IFF_NOARP; From ee705fa21fdc0c7da98309e5c3c8ab72b99ef087 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Tue, 1 Apr 2025 09:34:48 -0700 Subject: [PATCH 7/8] docs: net: document netdev notifier expectations We don't have a consistent state yet, but document where we think we are and where we wanna be. Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20250401163452.622454-8-sdf@fomichev.me Signed-off-by: Jakub Kicinski --- Documentation/networking/netdevices.rst | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/Documentation/networking/netdevices.rst b/Documentation/networking/netdevices.rst index ebb868f50ac2..6c2d8945f597 100644 --- a/Documentation/networking/netdevices.rst +++ b/Documentation/networking/netdevices.rst @@ -343,6 +343,29 @@ there are two sets of interfaces: ``dev_xxx`` and ``netif_xxx`` (e.g., acquiring the instance lock themselves, while the ``netif_xxx`` functions assume that the driver has already acquired the instance lock. +Notifiers and netdev instance lock +================================== + +For device drivers that implement shaping or queue management APIs, +some of the notifiers (``enum netdev_cmd``) are running under the netdev +instance lock. + +For devices with locked ops, currently only the following notifiers are +running under the lock: +* ``NETDEV_REGISTER`` +* ``NETDEV_UP`` + +The following notifiers are running without the lock: +* ``NETDEV_UNREGISTER`` + +There are no clear expectations for the remaining notifiers. Notifiers not on +the list may run with or without the instance lock, potentially even invoking +the same notifier type with and without the lock from different code paths. +The goal is to eventually ensure that all (or most, with a few documented +exceptions) notifiers run under the instance lock. Please extend this +documentation whenever you make explicit assumption about lock being held +from a notifier. + NETDEV_INTERNAL symbol namespace ================================ From 56c8a23f8a0f3c735f3b8f9d323927904090049b Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Tue, 1 Apr 2025 09:34:49 -0700 Subject: [PATCH 8/8] selftests: net: use netdevsim in netns test Netdevsim has extra register_netdevice_notifier_dev_net notifiers, use netdevim instead of dummy device to test them out. Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20250401163452.622454-9-sdf@fomichev.me Signed-off-by: Jakub Kicinski --- tools/testing/selftests/net/lib.sh | 25 +++++++++++++++++++++++ tools/testing/selftests/net/netns-name.sh | 13 ++++++++---- 2 files changed, 34 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/net/lib.sh b/tools/testing/selftests/net/lib.sh index 975be4fdbcdb..701905eeff66 100644 --- a/tools/testing/selftests/net/lib.sh +++ b/tools/testing/selftests/net/lib.sh @@ -222,6 +222,31 @@ setup_ns() NS_LIST+=("${ns_list[@]}") } +# Create netdevsim with given id and net namespace. +create_netdevsim() { + local id="$1" + local ns="$2" + + modprobe netdevsim &> /dev/null + udevadm settle + + echo "$id 1" | ip netns exec $ns tee /sys/bus/netdevsim/new_device >/dev/null + local dev=$(ip netns exec $ns ls /sys/bus/netdevsim/devices/netdevsim$id/net) + ip -netns $ns link set dev $dev name nsim$id + ip -netns $ns link set dev nsim$id up + + echo nsim$id +} + +# Remove netdevsim with given id. +cleanup_netdevsim() { + local id="$1" + + if [ -d "/sys/bus/netdevsim/devices/netdevsim$id/net" ]; then + echo "$id" > /sys/bus/netdevsim/del_device + fi +} + tc_rule_stats_get() { local dev=$1; shift diff --git a/tools/testing/selftests/net/netns-name.sh b/tools/testing/selftests/net/netns-name.sh index 0be1905d1f2f..38871bdef67f 100755 --- a/tools/testing/selftests/net/netns-name.sh +++ b/tools/testing/selftests/net/netns-name.sh @@ -7,10 +7,12 @@ set -o pipefail DEV=dummy-dev0 DEV2=dummy-dev1 ALT_NAME=some-alt-name +NSIM_ADDR=2025 RET_CODE=0 cleanup() { + cleanup_netdevsim $NSIM_ADDR cleanup_ns $NS $test_ns } @@ -25,12 +27,15 @@ setup_ns NS test_ns # # Test basic move without a rename +# Use netdevsim because it has extra asserts for notifiers. # -ip -netns $NS link add name $DEV type dummy || fail -ip -netns $NS link set dev $DEV netns $test_ns || + +nsim=$(create_netdevsim $NSIM_ADDR $NS) +ip -netns $NS link set dev $nsim netns $test_ns || fail "Can't perform a netns move" -ip -netns $test_ns link show dev $DEV >> /dev/null || fail "Device not found after move" -ip -netns $test_ns link del $DEV || fail +ip -netns $test_ns link show dev $nsim >> /dev/null || + fail "Device not found after move" +cleanup_netdevsim $NSIM_ADDR # # Test move with a conflict