diff options
| -rw-r--r-- | include/linux/rtnetlink.h | 69 | ||||
| -rw-r--r-- | include/net/net_namespace.h | 4 | ||||
| -rw-r--r-- | net/Kconfig.debug | 15 | ||||
| -rw-r--r-- | net/core/Makefile | 1 | ||||
| -rw-r--r-- | net/core/net_namespace.c | 6 | ||||
| -rw-r--r-- | net/core/rtnetlink.c | 70 | ||||
| -rw-r--r-- | net/core/rtnl_net_debug.c | 131 |
7 files changed, 289 insertions, 7 deletions
diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h index a7da7dfc06a2..8468a4ce8510 100644 --- a/include/linux/rtnetlink.h +++ b/include/linux/rtnetlink.h @@ -7,7 +7,6 @@ #include <linux/netdevice.h> #include <linux/wait.h> #include <linux/refcount.h> -#include <linux/cleanup.h> #include <uapi/linux/rtnetlink.h> extern int rtnetlink_send(struct sk_buff *skb, struct net *net, u32 pid, u32 group, int echo); @@ -47,13 +46,15 @@ extern int rtnl_is_locked(void); extern int rtnl_lock_killable(void); extern bool refcount_dec_and_rtnl_lock(refcount_t *r); -DEFINE_LOCK_GUARD_0(rtnl, rtnl_lock(), rtnl_unlock()) - extern wait_queue_head_t netdev_unregistering_wq; extern atomic_t dev_unreg_count; extern struct rw_semaphore pernet_ops_rwsem; extern struct rw_semaphore net_rwsem; +#define ASSERT_RTNL() \ + WARN_ONCE(!rtnl_is_locked(), \ + "RTNL: assertion failed at %s (%d)\n", __FILE__, __LINE__) + #ifdef CONFIG_PROVE_LOCKING extern bool lockdep_rtnl_is_held(void); #else @@ -95,6 +96,64 @@ static inline bool lockdep_rtnl_is_held(void) #define rcu_replace_pointer_rtnl(rp, p) \ rcu_replace_pointer(rp, p, lockdep_rtnl_is_held()) +#ifdef CONFIG_DEBUG_NET_SMALL_RTNL +void __rtnl_net_lock(struct net *net); +void __rtnl_net_unlock(struct net *net); +void rtnl_net_lock(struct net *net); +void rtnl_net_unlock(struct net *net); +int rtnl_net_lock_cmp_fn(const struct lockdep_map *a, const struct lockdep_map *b); + +bool rtnl_net_is_locked(struct net *net); + +#define ASSERT_RTNL_NET(net) \ + WARN_ONCE(!rtnl_net_is_locked(net), \ + "RTNL_NET: assertion failed at %s (%d)\n", \ + __FILE__, __LINE__) + +bool lockdep_rtnl_net_is_held(struct net *net); + +#define rcu_dereference_rtnl_net(net, p) \ + rcu_dereference_check(p, lockdep_rtnl_net_is_held(net)) +#define rtnl_net_dereference(net, p) \ + rcu_dereference_protected(p, lockdep_rtnl_net_is_held(net)) +#define rcu_replace_pointer_rtnl_net(net, rp, p) \ + rcu_replace_pointer(rp, p, lockdep_rtnl_net_is_held(net)) +#else +static inline void __rtnl_net_lock(struct net *net) {} +static inline void __rtnl_net_unlock(struct net *net) {} + +static inline void rtnl_net_lock(struct net *net) +{ + rtnl_lock(); +} + +static inline void rtnl_net_unlock(struct net *net) +{ + rtnl_unlock(); +} + +static inline void ASSERT_RTNL_NET(struct net *net) +{ + ASSERT_RTNL(); +} + +static inline void *rcu_dereference_rtnl_net(struct net *net, void *p) +{ + return rcu_dereference_rtnl(p); +} + +static inline void *rtnl_net_dereference(struct net *net, void *p) +{ + return rtnl_dereference(p); +} + +static inline void *rcu_replace_pointer_rtnl_net(struct net *net, + void *rp, void *p) +{ + return rcu_replace_pointer_rtnl(rp, p); +} +#endif + static inline struct netdev_queue *dev_ingress_queue(struct net_device *dev) { return rtnl_dereference(dev->ingress_queue); @@ -122,10 +181,6 @@ void rtnetlink_init(void); void __rtnl_unlock(void); void rtnl_kfree_skbs(struct sk_buff *head, struct sk_buff *tail); -#define ASSERT_RTNL() \ - WARN_ONCE(!rtnl_is_locked(), \ - "RTNL: assertion failed at %s (%d)\n", __FILE__, __LINE__) - extern int ndo_dflt_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb, struct net_device *dev, diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index e67b483cc8bb..873c0f9fdac6 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -188,6 +188,10 @@ struct net { #if IS_ENABLED(CONFIG_SMC) struct netns_smc smc; #endif +#ifdef CONFIG_DEBUG_NET_SMALL_RTNL + /* Move to a better place when the config guard is removed. */ + struct mutex rtnl_mutex; +#endif } __randomize_layout; #include <linux/seq_file_net.h> diff --git a/net/Kconfig.debug b/net/Kconfig.debug index 5e3fffe707dd..277fab8c4d77 100644 --- a/net/Kconfig.debug +++ b/net/Kconfig.debug @@ -24,3 +24,18 @@ config DEBUG_NET help Enable extra sanity checks in networking. This is mostly used by fuzzers, but is safe to select. + +config DEBUG_NET_SMALL_RTNL + bool "Add extra per-netns mutex inside RTNL" + depends on DEBUG_KERNEL && NET && LOCK_DEBUGGING_SUPPORT + select PROVE_LOCKING + default n + help + rtnl_lock() is being replaced with rtnl_net_lock() that + acquires the global RTNL and a small per-netns RTNL mutex. + + During the conversion, rtnl_net_lock() just adds an extra + mutex in every RTNL scope and slows down the operations. + + Once the conversion completes, rtnl_lock() will be removed + and rtnetlink will gain per-netns scalability. diff --git a/net/core/Makefile b/net/core/Makefile index c3ebbaf9c81e..5a72a87ee0f1 100644 --- a/net/core/Makefile +++ b/net/core/Makefile @@ -45,3 +45,4 @@ 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 diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index e39479f1c9a4..105e3cd26763 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -334,6 +334,12 @@ static __net_init void preinit_net(struct net *net, struct user_namespace *user_ idr_init(&net->netns_ids); spin_lock_init(&net->nsid_lock); mutex_init(&net->ipv4.ra_mutex); + +#ifdef CONFIG_DEBUG_NET_SMALL_RTNL + mutex_init(&net->rtnl_mutex); + lock_set_cmp_fn(&net->rtnl_mutex, rtnl_net_lock_cmp_fn, NULL); +#endif + preinit_net_sysctl(net); } diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 682d8d3127db..6d68247aea70 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -179,6 +179,76 @@ bool lockdep_rtnl_is_held(void) EXPORT_SYMBOL(lockdep_rtnl_is_held); #endif /* #ifdef CONFIG_PROVE_LOCKING */ +#ifdef CONFIG_DEBUG_NET_SMALL_RTNL +void __rtnl_net_lock(struct net *net) +{ + ASSERT_RTNL(); + + mutex_lock(&net->rtnl_mutex); +} +EXPORT_SYMBOL(__rtnl_net_lock); + +void __rtnl_net_unlock(struct net *net) +{ + ASSERT_RTNL(); + + mutex_unlock(&net->rtnl_mutex); +} +EXPORT_SYMBOL(__rtnl_net_unlock); + +void rtnl_net_lock(struct net *net) +{ + rtnl_lock(); + __rtnl_net_lock(net); +} +EXPORT_SYMBOL(rtnl_net_lock); + +void rtnl_net_unlock(struct net *net) +{ + __rtnl_net_unlock(net); + rtnl_unlock(); +} +EXPORT_SYMBOL(rtnl_net_unlock); + +static int rtnl_net_cmp_locks(const struct net *net_a, const struct net *net_b) +{ + if (net_eq(net_a, net_b)) + return 0; + + /* always init_net first */ + if (net_eq(net_a, &init_net)) + return -1; + + if (net_eq(net_b, &init_net)) + return 1; + + /* otherwise lock in ascending order */ + return net_a < net_b ? -1 : 1; +} + +int rtnl_net_lock_cmp_fn(const struct lockdep_map *a, const struct lockdep_map *b) +{ + const struct net *net_a, *net_b; + + net_a = container_of(a, struct net, rtnl_mutex.dep_map); + net_b = container_of(b, struct net, rtnl_mutex.dep_map); + + return rtnl_net_cmp_locks(net_a, net_b); +} + +bool rtnl_net_is_locked(struct net *net) +{ + return rtnl_is_locked() && mutex_is_locked(&net->rtnl_mutex); +} +EXPORT_SYMBOL(rtnl_net_is_locked); + +bool lockdep_rtnl_net_is_held(struct net *net) +{ + return lockdep_rtnl_is_held() && lockdep_is_held(&net->rtnl_mutex); +} +EXPORT_SYMBOL(lockdep_rtnl_net_is_held); +#endif + static struct rtnl_link __rcu *__rcu *rtnl_msg_handlers[RTNL_FAMILY_MAX + 1]; static inline int rtm_msgindex(int msgtype) diff --git a/net/core/rtnl_net_debug.c b/net/core/rtnl_net_debug.c new file mode 100644 index 000000000000..e90a32242e22 --- /dev/null +++ b/net/core/rtnl_net_debug.c @@ -0,0 +1,131 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Copyright Amazon.com Inc. or its affiliates. */ + +#include <linux/init.h> +#include <linux/netdevice.h> +#include <linux/notifier.h> +#include <linux/rtnetlink.h> +#include <net/net_namespace.h> +#include <net/netns/generic.h> + +static int rtnl_net_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); + enum netdev_cmd cmd = event; + + /* Keep enum and don't add default to trigger -Werror=switch */ + switch (cmd) { + case NETDEV_UP: + case NETDEV_DOWN: + case NETDEV_REBOOT: + case NETDEV_CHANGE: + case NETDEV_REGISTER: + case NETDEV_UNREGISTER: + case NETDEV_CHANGEMTU: + case NETDEV_CHANGEADDR: + case NETDEV_PRE_CHANGEADDR: + case NETDEV_GOING_DOWN: + case NETDEV_CHANGENAME: + case NETDEV_FEAT_CHANGE: + case NETDEV_BONDING_FAILOVER: + case NETDEV_PRE_UP: + case NETDEV_PRE_TYPE_CHANGE: + case NETDEV_POST_TYPE_CHANGE: + case NETDEV_POST_INIT: + case NETDEV_PRE_UNINIT: + case NETDEV_RELEASE: + case NETDEV_NOTIFY_PEERS: + case NETDEV_JOIN: + case NETDEV_CHANGEUPPER: + case NETDEV_RESEND_IGMP: + case NETDEV_PRECHANGEMTU: + case NETDEV_CHANGEINFODATA: + case NETDEV_BONDING_INFO: + case NETDEV_PRECHANGEUPPER: + case NETDEV_CHANGELOWERSTATE: + case NETDEV_UDP_TUNNEL_PUSH_INFO: + case NETDEV_UDP_TUNNEL_DROP_INFO: + case NETDEV_CHANGE_TX_QUEUE_LEN: + case NETDEV_CVLAN_FILTER_PUSH_INFO: + case NETDEV_CVLAN_FILTER_DROP_INFO: + case NETDEV_SVLAN_FILTER_PUSH_INFO: + case NETDEV_SVLAN_FILTER_DROP_INFO: + case NETDEV_OFFLOAD_XSTATS_ENABLE: + case NETDEV_OFFLOAD_XSTATS_DISABLE: + case NETDEV_OFFLOAD_XSTATS_REPORT_USED: + case NETDEV_OFFLOAD_XSTATS_REPORT_DELTA: + case NETDEV_XDP_FEAT_CHANGE: + ASSERT_RTNL(); + break; + + /* Once an event fully supports RTNL_NET, move it here + * and remove "if (0)" below. + * + * case NETDEV_XXX: + * ASSERT_RTNL_NET(net); + * break; + */ + } + + /* Just to avoid unused-variable error for dev and net. */ + if (0) + ASSERT_RTNL_NET(net); + + return NOTIFY_DONE; +} + +static int rtnl_net_debug_net_id; + +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; + + return register_netdevice_notifier_net(net, nb); +} + +static void __net_exit rtnl_net_debug_net_exit(struct net *net) +{ + struct notifier_block *nb; + + nb = net_generic(net, rtnl_net_debug_net_id); + unregister_netdevice_notifier_net(net, nb); +} + +static struct pernet_operations rtnl_net_debug_net_ops __net_initdata = { + .init = rtnl_net_debug_net_init, + .exit = rtnl_net_debug_net_exit, + .id = &rtnl_net_debug_net_id, + .size = sizeof(struct notifier_block), +}; + +static struct notifier_block rtnl_net_debug_block = { + .notifier_call = rtnl_net_debug_event, +}; + +static int __init rtnl_net_debug_init(void) +{ + int ret; + + ret = register_pernet_device(&rtnl_net_debug_net_ops); + if (ret) + return ret; + + ret = register_netdevice_notifier(&rtnl_net_debug_block); + if (ret) + unregister_pernet_subsys(&rtnl_net_debug_net_ops); + + return ret; +} + +static void __exit rtnl_net_debug_exit(void) +{ + unregister_netdevice_notifier(&rtnl_net_debug_block); + unregister_pernet_device(&rtnl_net_debug_net_ops); +} + +subsys_initcall(rtnl_net_debug_init); |