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, 45 insertions, 0 deletions

diff --git a/drivers/net/phy/sfp.h b/drivers/net/phy/sfp.h
new file mode 100644
index 000000000..19fe29d84
--- /dev/null
+++ b/drivers/net/phy/sfp.h
@@ -0,0 +1,45 @@
+#ifndef SFP_H
+#define SFP_H
+
+#include <linux/ethtool.h>
+#include <linux/sfp.h>
+
+struct sfp;
+
+struct sfp_quirk {
+	const char *vendor;
+	const char *part;
+	void (*support)(const struct sfp_eeprom_id *id,
+			struct sfp_module_caps *caps);
+	void (*fixup)(struct sfp *sfp);
+	bool part_prefix_match;
+};
+
+struct sfp_socket_ops {
+	void (*attach)(struct sfp *sfp);
+	void (*detach)(struct sfp *sfp);
+	void (*start)(struct sfp *sfp);
+	void (*stop)(struct sfp *sfp);
+	void (*set_signal_rate)(struct sfp *sfp, unsigned int rate_kbd);
+	int (*module_info)(struct sfp *sfp, struct ethtool_modinfo *modinfo);
+	int (*module_eeprom)(struct sfp *sfp, struct ethtool_eeprom *ee,
+			     u8 *data);
+	int (*module_eeprom_by_page)(struct sfp *sfp,
+				     const struct ethtool_module_eeprom *page,
+				     struct netlink_ext_ack *extack);
+};
+
+int sfp_add_phy(struct sfp_bus *bus, struct phy_device *phydev);
+void sfp_remove_phy(struct sfp_bus *bus);
+void sfp_link_up(struct sfp_bus *bus);
+void sfp_link_down(struct sfp_bus *bus);
+int sfp_module_insert(struct sfp_bus *bus, const struct sfp_eeprom_id *id,
+		      const struct sfp_quirk *quirk);
+void sfp_module_remove(struct sfp_bus *bus);
+int sfp_module_start(struct sfp_bus *bus);
+void sfp_module_stop(struct sfp_bus *bus);
+struct sfp_bus *sfp_register_socket(struct device *dev, struct sfp *sfp,
+				    const struct sfp_socket_ops *ops);
+void sfp_unregister_socket(struct sfp_bus *bus);
+
+#endif