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, 149 insertions, 0 deletions

diff --git a/net/batman-adv/hard-interface.h b/net/batman-adv/hard-interface.h
new file mode 100644
index 000000000..935f47ca9
--- /dev/null
+++ b/net/batman-adv/hard-interface.h
@@ -0,0 +1,149 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) B.A.T.M.A.N. contributors:
+ *
+ * Marek Lindner, Simon Wunderlich
+ */
+
+#ifndef _NET_BATMAN_ADV_HARD_INTERFACE_H_
+#define _NET_BATMAN_ADV_HARD_INTERFACE_H_
+
+#include "main.h"
+
+#include <linux/compiler.h>
+#include <linux/init.h>
+#include <linux/kref.h>
+#include <linux/netdevice.h>
+#include <linux/rcupdate.h>
+#include <linux/stddef.h>
+#include <linux/types.h>
+
+/**
+ * enum batadv_hard_if_state - State of a hard interface
+ */
+enum batadv_hard_if_state {
+	/**
+	 * @BATADV_IF_TO_BE_REMOVED: interface will be removed from mesh
+	 * interface
+	 */
+	BATADV_IF_TO_BE_REMOVED,
+
+	/** @BATADV_IF_INACTIVE: interface is deactivated */
+	BATADV_IF_INACTIVE,
+
+	/** @BATADV_IF_ACTIVE: interface is used */
+	BATADV_IF_ACTIVE,
+
+	/** @BATADV_IF_TO_BE_ACTIVATED: interface is getting activated */
+	BATADV_IF_TO_BE_ACTIVATED,
+};
+
+/**
+ * enum batadv_hard_if_bcast - broadcast avoidance options
+ */
+enum batadv_hard_if_bcast {
+	/** @BATADV_HARDIF_BCAST_OK: Do broadcast on according hard interface */
+	BATADV_HARDIF_BCAST_OK = 0,
+
+	/**
+	 * @BATADV_HARDIF_BCAST_NORECIPIENT: Broadcast not needed, there is no
+	 *  recipient
+	 */
+	BATADV_HARDIF_BCAST_NORECIPIENT,
+
+	/**
+	 * @BATADV_HARDIF_BCAST_DUPFWD: There is just the neighbor we got it
+	 *  from
+	 */
+	BATADV_HARDIF_BCAST_DUPFWD,
+
+	/** @BATADV_HARDIF_BCAST_DUPORIG: There is just the originator */
+	BATADV_HARDIF_BCAST_DUPORIG,
+};
+
+extern struct notifier_block batadv_hard_if_notifier;
+
+struct net_device *__batadv_get_real_netdev(struct net_device *net_device);
+struct net_device *batadv_get_real_netdev(struct net_device *net_device);
+u32 batadv_netdev_get_wifi_flags(struct net_device *net_dev);
+u32 batadv_hardif_get_wifi_flags(struct batadv_hard_iface *hard_iface);
+bool batadv_is_wifi_hardif(struct batadv_hard_iface *hard_iface);
+struct batadv_hard_iface*
+batadv_hardif_get_by_netdev(struct net_device *net_dev);
+int batadv_hardif_enable_interface(struct net_device *net_dev,
+				   struct net_device *mesh_iface);
+void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface);
+int batadv_hardif_min_mtu(struct net_device *mesh_iface);
+void batadv_update_min_mtu(struct net_device *mesh_iface);
+void batadv_hardif_release(struct kref *ref);
+int batadv_hardif_no_broadcast(struct batadv_hard_iface *if_outgoing,
+			       u8 *orig_addr, u8 *orig_neigh);
+int __init batadv_wifi_net_devices_init(void);
+void batadv_wifi_net_devices_deinit(void);
+
+/**
+ * batadv_hardif_put() - decrement the hard interface refcounter and possibly
+ *  release it
+ * @hard_iface: the hard interface to free
+ */
+static inline void batadv_hardif_put(struct batadv_hard_iface *hard_iface)
+{
+	if (!hard_iface)
+		return;
+
+	kref_put(&hard_iface->refcount, batadv_hardif_release);
+}
+
+/**
+ * batadv_primary_if_get_selected() - Get reference to primary interface
+ * @bat_priv: the bat priv with all the mesh interface information
+ *
+ * Return: primary interface (with increased refcnt), otherwise NULL
+ */
+static inline struct batadv_hard_iface *
+batadv_primary_if_get_selected(struct batadv_priv *bat_priv)
+{
+	struct batadv_hard_iface *hard_iface;
+
+	rcu_read_lock();
+	hard_iface = rcu_dereference(bat_priv->primary_if);
+	if (!hard_iface)
+		goto out;
+
+	if (!kref_get_unless_zero(&hard_iface->refcount))
+		hard_iface = NULL;
+
+out:
+	rcu_read_unlock();
+	return hard_iface;
+}
+
+/**
+ * batadv_is_cfg80211() - check if the given hardif is a cfg80211
+ *  wifi interface
+ * @wifi_flags: extracted batadv_hard_iface_wifi_flags of a net_device
+ *
+ * Return: true if the net device is a cfg80211 wireless device, false
+ *  otherwise.
+ */
+static inline bool batadv_is_cfg80211(u32 wifi_flags)
+{
+	u32 allowed_flags = 0;
+
+	allowed_flags |= BATADV_HARDIF_WIFI_CFG80211_DIRECT;
+	allowed_flags |= BATADV_HARDIF_WIFI_CFG80211_INDIRECT;
+
+	return !!(wifi_flags & allowed_flags);
+}
+
+/**
+ * batadv_is_wifi() - check if flags belong to wifi interface
+ * @wifi_flags: extracted batadv_hard_iface_wifi_flags of a net_device
+ *
+ * Return: true if the net device is a 802.11 wireless device, false otherwise.
+ */
+static inline bool batadv_is_wifi(u32 wifi_flags)
+{
+	return wifi_flags != 0;
+}
+
+#endif /* _NET_BATMAN_ADV_HARD_INTERFACE_H_ */