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 --- include/net/arp.h | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 include/net/arp.h (limited to 'include/net/arp.h') diff --git a/include/net/arp.h b/include/net/arp.h new file mode 100644 index 000000000..e8747e071 --- /dev/null +++ b/include/net/arp.h @@ -0,0 +1,77 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* linux/net/inet/arp.h */ +#ifndef _ARP_H +#define _ARP_H + +#include +#include +#include + + +extern struct neigh_table arp_tbl; + +static inline u32 arp_hashfn(const void *pkey, const struct net_device *dev, u32 *hash_rnd) +{ + u32 key = *(const u32 *)pkey; + u32 val = key ^ hash32_ptr(dev); + + return val * hash_rnd[0]; +} + +#ifdef CONFIG_INET +static inline struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key) +{ + if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) + key = INADDR_ANY; + + return ___neigh_lookup_noref(&arp_tbl, neigh_key_eq32, arp_hashfn, &key, dev); +} +#else +static inline +struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key) +{ + return NULL; +} +#endif + +static inline struct neighbour *__ipv4_neigh_lookup(struct net_device *dev, u32 key) +{ + struct neighbour *n; + + rcu_read_lock(); + n = __ipv4_neigh_lookup_noref(dev, key); + if (n && !refcount_inc_not_zero(&n->refcnt)) + n = NULL; + rcu_read_unlock(); + + return n; +} + +static inline void __ipv4_confirm_neigh(struct net_device *dev, u32 key) +{ + struct neighbour *n; + + rcu_read_lock(); + n = __ipv4_neigh_lookup_noref(dev, key); + neigh_confirm(n); + rcu_read_unlock(); +} + +void arp_init(void); +int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg); +void arp_send(int type, int ptype, __be32 dest_ip, + struct net_device *dev, __be32 src_ip, + const unsigned char *dest_hw, + const unsigned char *src_hw, const unsigned char *th); +int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir); +void arp_ifdown(struct net_device *dev); +int arp_invalidate(struct net_device *dev, __be32 ip, bool force); + +struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, + struct net_device *dev, __be32 src_ip, + const unsigned char *dest_hw, + const unsigned char *src_hw, + const unsigned char *target_hw); +void arp_xmit(struct sk_buff *skb); + +#endif /* _ARP_H */ -- cgit v1.3.1