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, 41 insertions, 0 deletions

diff --git a/drivers/net/phy/phylib.h b/drivers/net/phy/phylib.h
new file mode 100644
index 000000000..c6e26ac6b
--- /dev/null
+++ b/drivers/net/phy/phylib.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * phylib header
+ */
+
+#ifndef __PHYLIB_H
+#define __PHYLIB_H
+
+struct device_node;
+struct phy_device;
+struct mii_bus;
+
+struct device_node *phy_package_get_node(struct phy_device *phydev);
+void *phy_package_get_priv(struct phy_device *phydev);
+void phy_package_lock(struct phy_device *phydev);
+void phy_package_unlock(struct phy_device *phydev);
+int __phy_package_read(struct phy_device *phydev, unsigned int addr_offset,
+		       u32 regnum);
+int __phy_package_write(struct phy_device *phydev, unsigned int addr_offset,
+			u32 regnum, u16 val);
+int __phy_package_read_mmd(struct phy_device *phydev,
+			   unsigned int addr_offset, int devad,
+			   u32 regnum);
+int __phy_package_write_mmd(struct phy_device *phydev,
+			    unsigned int addr_offset, int devad,
+			    u32 regnum, u16 val);
+bool phy_package_init_once(struct phy_device *phydev);
+bool phy_package_probe_once(struct phy_device *phydev);
+int phy_package_join(struct phy_device *phydev, int base_addr, size_t priv_size);
+int of_phy_package_join(struct phy_device *phydev, size_t priv_size);
+void phy_package_leave(struct phy_device *phydev);
+int devm_phy_package_join(struct device *dev, struct phy_device *phydev,
+			  int base_addr, size_t priv_size);
+int devm_of_phy_package_join(struct device *dev, struct phy_device *phydev,
+			     size_t priv_size);
+int mmd_phy_read(struct mii_bus *bus, int phy_addr, bool is_c45,
+		 int devad, u32 regnum);
+int mmd_phy_write(struct mii_bus *bus, int phy_addr, bool is_c45,
+		  int devad, u32 regnum, u16 val);
+
+#endif /* __PHYLIB_H */