ftrace: Synchronize the initialization of ftrace_opsgrafted

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 <rostedt@goodmis.org>

1 files changed, 186 insertions, 0 deletions

diff --git a/net/batman-adv/distributed-arp-table.h b/net/batman-adv/distributed-arp-table.h
new file mode 100644
index 000000000..e7b75e82e
--- /dev/null
+++ b/net/batman-adv/distributed-arp-table.h
@@ -0,0 +1,186 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) B.A.T.M.A.N. contributors:
+ *
+ * Antonio Quartulli
+ */
+
+#ifndef _NET_BATMAN_ADV_DISTRIBUTED_ARP_TABLE_H_
+#define _NET_BATMAN_ADV_DISTRIBUTED_ARP_TABLE_H_
+
+#include "main.h"
+
+#include <linux/compiler.h>
+#include <linux/netdevice.h>
+#include <linux/netlink.h>
+#include <linux/skbuff.h>
+#include <linux/types.h>
+#include <uapi/linux/batadv_packet.h>
+
+#include "originator.h"
+
+#ifdef CONFIG_BATMAN_ADV_DAT
+
+/* BATADV_DAT_ADDR_MAX - maximum address value in the DHT space */
+#define BATADV_DAT_ADDR_MAX ((batadv_dat_addr_t)~(batadv_dat_addr_t)0)
+
+void batadv_dat_status_update(struct net_device *net_dev);
+bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
+					   struct sk_buff *skb);
+bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv,
+					   struct sk_buff *skb, int hdr_size);
+void batadv_dat_snoop_outgoing_arp_reply(struct batadv_priv *bat_priv,
+					 struct sk_buff *skb);
+bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv,
+					 struct sk_buff *skb, int hdr_size);
+void batadv_dat_snoop_outgoing_dhcp_ack(struct batadv_priv *bat_priv,
+					struct sk_buff *skb,
+					__be16 proto,
+					unsigned short vid);
+void batadv_dat_snoop_incoming_dhcp_ack(struct batadv_priv *bat_priv,
+					struct sk_buff *skb, int hdr_size);
+bool batadv_dat_drop_broadcast_packet(struct batadv_priv *bat_priv,
+				      struct batadv_forw_packet *forw_packet);
+
+/**
+ * batadv_dat_init_orig_node_addr() - assign a DAT address to the orig_node
+ * @orig_node: the node to assign the DAT address to
+ */
+static inline void
+batadv_dat_init_orig_node_addr(struct batadv_orig_node *orig_node)
+{
+	u32 addr;
+
+	addr = batadv_choose_orig(orig_node->orig, BATADV_DAT_ADDR_MAX);
+	orig_node->dat_addr = (batadv_dat_addr_t)addr;
+}
+
+/**
+ * batadv_dat_init_own_addr() - assign a DAT address to the node itself
+ * @bat_priv: the bat priv with all the mesh interface information
+ * @primary_if: a pointer to the primary interface
+ */
+static inline void
+batadv_dat_init_own_addr(struct batadv_priv *bat_priv,
+			 struct batadv_hard_iface *primary_if)
+{
+	u32 addr;
+
+	addr = batadv_choose_orig(primary_if->net_dev->dev_addr,
+				  BATADV_DAT_ADDR_MAX);
+
+	bat_priv->dat.addr = (batadv_dat_addr_t)addr;
+}
+
+int batadv_dat_init(struct batadv_priv *bat_priv);
+void batadv_dat_free(struct batadv_priv *bat_priv);
+int batadv_dat_cache_dump(struct sk_buff *msg, struct netlink_callback *cb);
+
+/**
+ * batadv_dat_inc_counter() - increment the correct DAT packet counter
+ * @bat_priv: the bat priv with all the mesh interface information
+ * @subtype: the 4addr subtype of the packet to be counted
+ *
+ * Updates the ethtool statistics for the received packet if it is a DAT subtype
+ */
+static inline void batadv_dat_inc_counter(struct batadv_priv *bat_priv,
+					  u8 subtype)
+{
+	switch (subtype) {
+	case BATADV_P_DAT_DHT_GET:
+		batadv_inc_counter(bat_priv,
+				   BATADV_CNT_DAT_GET_RX);
+		break;
+	case BATADV_P_DAT_DHT_PUT:
+		batadv_inc_counter(bat_priv,
+				   BATADV_CNT_DAT_PUT_RX);
+		break;
+	}
+}
+
+#else
+
+static inline void batadv_dat_status_update(struct net_device *net_dev)
+{
+}
+
+static inline bool
+batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
+				      struct sk_buff *skb)
+{
+	return false;
+}
+
+static inline bool
+batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv,
+				      struct sk_buff *skb, int hdr_size)
+{
+	return false;
+}
+
+static inline bool
+batadv_dat_snoop_outgoing_arp_reply(struct batadv_priv *bat_priv,
+				    struct sk_buff *skb)
+{
+	return false;
+}
+
+static inline bool
+batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv,
+				    struct sk_buff *skb, int hdr_size)
+{
+	return false;
+}
+
+static inline void
+batadv_dat_snoop_outgoing_dhcp_ack(struct batadv_priv *bat_priv,
+				   struct sk_buff *skb, __be16 proto,
+				   unsigned short vid)
+{
+}
+
+static inline void
+batadv_dat_snoop_incoming_dhcp_ack(struct batadv_priv *bat_priv,
+				   struct sk_buff *skb, int hdr_size)
+{
+}
+
+static inline bool
+batadv_dat_drop_broadcast_packet(struct batadv_priv *bat_priv,
+				 struct batadv_forw_packet *forw_packet)
+{
+	return false;
+}
+
+static inline void
+batadv_dat_init_orig_node_addr(struct batadv_orig_node *orig_node)
+{
+}
+
+static inline void batadv_dat_init_own_addr(struct batadv_priv *bat_priv,
+					    struct batadv_hard_iface *iface)
+{
+}
+
+static inline int batadv_dat_init(struct batadv_priv *bat_priv)
+{
+	return 0;
+}
+
+static inline void batadv_dat_free(struct batadv_priv *bat_priv)
+{
+}
+
+static inline int
+batadv_dat_cache_dump(struct sk_buff *msg, struct netlink_callback *cb)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void batadv_dat_inc_counter(struct batadv_priv *bat_priv,
+					  u8 subtype)
+{
+}
+
+#endif /* CONFIG_BATMAN_ADV_DAT */
+
+#endif /* _NET_BATMAN_ADV_DISTRIBUTED_ARP_TABLE_H_ */