From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- net/ipv4/tunnel4.c | 298 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 298 insertions(+) create mode 100644 net/ipv4/tunnel4.c (limited to 'net/ipv4/tunnel4.c') diff --git a/net/ipv4/tunnel4.c b/net/ipv4/tunnel4.c new file mode 100644 index 000000000..4c1f836aa --- /dev/null +++ b/net/ipv4/tunnel4.c @@ -0,0 +1,298 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* tunnel4.c: Generic IP tunnel transformer. + * + * Copyright (C) 2003 David S. Miller (davem@redhat.com) + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static struct xfrm_tunnel __rcu *tunnel4_handlers __read_mostly; +static struct xfrm_tunnel __rcu *tunnel64_handlers __read_mostly; +static struct xfrm_tunnel __rcu *tunnelmpls4_handlers __read_mostly; +static DEFINE_MUTEX(tunnel4_mutex); + +static inline struct xfrm_tunnel __rcu **fam_handlers(unsigned short family) +{ + return (family == AF_INET) ? &tunnel4_handlers : + (family == AF_INET6) ? &tunnel64_handlers : + &tunnelmpls4_handlers; +} + +int xfrm4_tunnel_register(struct xfrm_tunnel *handler, unsigned short family) +{ + struct xfrm_tunnel __rcu **pprev; + struct xfrm_tunnel *t; + + int ret = -EEXIST; + int priority = handler->priority; + + mutex_lock(&tunnel4_mutex); + + for (pprev = fam_handlers(family); + (t = rcu_dereference_protected(*pprev, + lockdep_is_held(&tunnel4_mutex))) != NULL; + pprev = &t->next) { + if (t->priority > priority) + break; + if (t->priority == priority) + goto err; + } + + handler->next = *pprev; + rcu_assign_pointer(*pprev, handler); + + ret = 0; + +err: + mutex_unlock(&tunnel4_mutex); + + return ret; +} +EXPORT_SYMBOL(xfrm4_tunnel_register); + +int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler, unsigned short family) +{ + struct xfrm_tunnel __rcu **pprev; + struct xfrm_tunnel *t; + int ret = -ENOENT; + + mutex_lock(&tunnel4_mutex); + + for (pprev = fam_handlers(family); + (t = rcu_dereference_protected(*pprev, + lockdep_is_held(&tunnel4_mutex))) != NULL; + pprev = &t->next) { + if (t == handler) { + *pprev = handler->next; + ret = 0; + break; + } + } + + mutex_unlock(&tunnel4_mutex); + + synchronize_net(); + + return ret; +} +EXPORT_SYMBOL(xfrm4_tunnel_deregister); + +#define for_each_tunnel_rcu(head, handler) \ + for (handler = rcu_dereference(head); \ + handler != NULL; \ + handler = rcu_dereference(handler->next)) \ + +static int tunnel4_rcv(struct sk_buff *skb) +{ + struct xfrm_tunnel *handler; + + if (!pskb_may_pull(skb, sizeof(struct iphdr))) + goto drop; + + for_each_tunnel_rcu(tunnel4_handlers, handler) + if (!handler->handler(skb)) + return 0; + + icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0); + +drop: + kfree_skb(skb); + return 0; +} + +#if IS_ENABLED(CONFIG_INET_XFRM_TUNNEL) +static int tunnel4_rcv_cb(struct sk_buff *skb, u8 proto, int err) +{ + struct xfrm_tunnel __rcu *head; + struct xfrm_tunnel *handler; + int ret; + + head = (proto == IPPROTO_IPIP) ? tunnel4_handlers : tunnel64_handlers; + + for_each_tunnel_rcu(head, handler) { + if (handler->cb_handler) { + ret = handler->cb_handler(skb, err); + if (ret <= 0) + return ret; + } + } + + return 0; +} + +static const struct xfrm_input_afinfo tunnel4_input_afinfo = { + .family = AF_INET, + .is_ipip = true, + .callback = tunnel4_rcv_cb, +}; +#endif + +#if IS_ENABLED(CONFIG_IPV6) +static int tunnel64_rcv(struct sk_buff *skb) +{ + struct xfrm_tunnel *handler; + + if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) + goto drop; + + for_each_tunnel_rcu(tunnel64_handlers, handler) + if (!handler->handler(skb)) + return 0; + + icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0); + +drop: + kfree_skb(skb); + return 0; +} +#endif + +#if IS_ENABLED(CONFIG_MPLS) +static int tunnelmpls4_rcv(struct sk_buff *skb) +{ + struct xfrm_tunnel *handler; + + if (!pskb_may_pull(skb, sizeof(struct mpls_label))) + goto drop; + + for_each_tunnel_rcu(tunnelmpls4_handlers, handler) + if (!handler->handler(skb)) + return 0; + + icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0); + +drop: + kfree_skb(skb); + return 0; +} +#endif + +static int tunnel4_err(struct sk_buff *skb, u32 info) +{ + struct xfrm_tunnel *handler; + + for_each_tunnel_rcu(tunnel4_handlers, handler) + if (!handler->err_handler(skb, info)) + return 0; + + return -ENOENT; +} + +#if IS_ENABLED(CONFIG_IPV6) +static int tunnel64_err(struct sk_buff *skb, u32 info) +{ + struct xfrm_tunnel *handler; + + for_each_tunnel_rcu(tunnel64_handlers, handler) + if (!handler->err_handler(skb, info)) + return 0; + + return -ENOENT; +} +#endif + +#if IS_ENABLED(CONFIG_MPLS) +static int tunnelmpls4_err(struct sk_buff *skb, u32 info) +{ + struct xfrm_tunnel *handler; + + for_each_tunnel_rcu(tunnelmpls4_handlers, handler) + if (!handler->err_handler(skb, info)) + return 0; + + return -ENOENT; +} +#endif + +static const struct net_protocol tunnel4_protocol = { + .handler = tunnel4_rcv, + .err_handler = tunnel4_err, + .no_policy = 1, +}; + +#if IS_ENABLED(CONFIG_IPV6) +static const struct net_protocol tunnel64_protocol = { + .handler = tunnel64_rcv, + .err_handler = tunnel64_err, + .no_policy = 1, +}; +#endif + +#if IS_ENABLED(CONFIG_MPLS) +static const struct net_protocol tunnelmpls4_protocol = { + .handler = tunnelmpls4_rcv, + .err_handler = tunnelmpls4_err, + .no_policy = 1, +}; +#endif + +static int __init tunnel4_init(void) +{ + if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP)) + goto err; +#if IS_ENABLED(CONFIG_IPV6) + if (inet_add_protocol(&tunnel64_protocol, IPPROTO_IPV6)) { + inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP); + goto err; + } +#endif +#if IS_ENABLED(CONFIG_MPLS) + if (inet_add_protocol(&tunnelmpls4_protocol, IPPROTO_MPLS)) { + inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP); +#if IS_ENABLED(CONFIG_IPV6) + inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6); +#endif + goto err; + } +#endif +#if IS_ENABLED(CONFIG_INET_XFRM_TUNNEL) + if (xfrm_input_register_afinfo(&tunnel4_input_afinfo)) { + inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP); +#if IS_ENABLED(CONFIG_IPV6) + inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6); +#endif +#if IS_ENABLED(CONFIG_MPLS) + inet_del_protocol(&tunnelmpls4_protocol, IPPROTO_MPLS); +#endif + goto err; + } +#endif + return 0; + +err: + pr_err("%s: can't add protocol\n", __func__); + return -EAGAIN; +} + +static void __exit tunnel4_fini(void) +{ +#if IS_ENABLED(CONFIG_INET_XFRM_TUNNEL) + if (xfrm_input_unregister_afinfo(&tunnel4_input_afinfo)) + pr_err("tunnel4 close: can't remove input afinfo\n"); +#endif +#if IS_ENABLED(CONFIG_MPLS) + if (inet_del_protocol(&tunnelmpls4_protocol, IPPROTO_MPLS)) + pr_err("tunnelmpls4 close: can't remove protocol\n"); +#endif +#if IS_ENABLED(CONFIG_IPV6) + if (inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6)) + pr_err("tunnel64 close: can't remove protocol\n"); +#endif + if (inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP)) + pr_err("tunnel4 close: can't remove protocol\n"); +} + +module_init(tunnel4_init); +module_exit(tunnel4_fini); +MODULE_DESCRIPTION("IPv4 XFRM tunnel library"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1