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, 32 insertions, 0 deletions

diff --git a/drivers/net/phy/phylib-internal.h b/drivers/net/phy/phylib-internal.h
new file mode 100644
index 000000000..664ed7faa
--- /dev/null
+++ b/drivers/net/phy/phylib-internal.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * phylib-internal header
+ */
+
+#ifndef __PHYLIB_INTERNAL_H
+#define __PHYLIB_INTERNAL_H
+
+struct mdio_device;
+struct phy_device;
+
+extern const struct bus_type mdio_bus_type;
+extern const struct class mdio_bus_class;
+
+/*
+ * phy_supported_speeds - return all speeds currently supported by a PHY device
+ */
+unsigned int phy_supported_speeds(struct phy_device *phy,
+				  unsigned int *speeds,
+				  unsigned int size);
+void of_set_phy_supported(struct phy_device *phydev);
+void of_set_phy_eee_broken(struct phy_device *phydev);
+void of_set_phy_timing_role(struct phy_device *phydev);
+int phy_speed_down_core(struct phy_device *phydev);
+void phy_check_downshift(struct phy_device *phydev);
+
+int mdiobus_register_device(struct mdio_device *mdiodev);
+int mdiobus_unregister_device(struct mdio_device *mdiodev);
+
+int genphy_c45_read_eee_adv(struct phy_device *phydev, unsigned long *adv);
+
+#endif /* __PHYLIB_INTERNAL_H */