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, 102 insertions, 0 deletions

diff --git a/drivers/net/phy/et1011c.c b/drivers/net/phy/et1011c.c
new file mode 100644
index 000000000..6cd8d7758
--- /dev/null
+++ b/drivers/net/phy/et1011c.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * drivers/net/phy/et1011c.c
+ *
+ * Driver for LSI ET1011C PHYs
+ *
+ * Author: Chaithrika U S
+ *
+ * Copyright (c) 2008 Texas Instruments
+ */
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/unistd.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/mii.h>
+#include <linux/ethtool.h>
+#include <linux/phy.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <asm/irq.h>
+
+#define ET1011C_STATUS_REG	(0x1A)
+#define ET1011C_CONFIG_REG	(0x16)
+#define ET1011C_SPEED_MASK		(0x0300)
+#define ET1011C_GIGABIT_SPEED		(0x0200)
+#define ET1011C_TX_FIFO_MASK		(0x3000)
+#define ET1011C_TX_FIFO_DEPTH_8		(0x0000)
+#define ET1011C_TX_FIFO_DEPTH_16	(0x1000)
+#define ET1011C_INTERFACE_MASK		(0x0007)
+#define ET1011C_GMII_INTERFACE		(0x0002)
+#define ET1011C_SYS_CLK_EN		(0x01 << 4)
+
+
+MODULE_DESCRIPTION("LSI ET1011C PHY driver");
+MODULE_AUTHOR("Chaithrika U S");
+MODULE_LICENSE("GPL");
+
+static int et1011c_config_aneg(struct phy_device *phydev)
+{
+	int ctl = phy_read(phydev, MII_BMCR);
+
+	if (ctl < 0)
+		return ctl;
+	ctl &= ~(BMCR_FULLDPLX | BMCR_SPEED100 | BMCR_SPEED1000 |
+		 BMCR_ANENABLE);
+	/* First clear the PHY */
+	phy_write(phydev, MII_BMCR, ctl | BMCR_RESET);
+
+	return genphy_config_aneg(phydev);
+}
+
+static int et1011c_read_status(struct phy_device *phydev)
+{
+	static int speed;
+	int ret;
+	u32 val;
+
+	ret = genphy_read_status(phydev);
+
+	if (speed != phydev->speed) {
+		speed = phydev->speed;
+		val = phy_read(phydev, ET1011C_STATUS_REG);
+		if ((val & ET1011C_SPEED_MASK) ==
+					ET1011C_GIGABIT_SPEED) {
+			val = phy_read(phydev, ET1011C_CONFIG_REG);
+			val &= ~ET1011C_TX_FIFO_MASK;
+			phy_write(phydev, ET1011C_CONFIG_REG, val |
+					  ET1011C_GMII_INTERFACE |
+					  ET1011C_SYS_CLK_EN |
+					  ET1011C_TX_FIFO_DEPTH_16);
+
+		}
+	}
+	return ret;
+}
+
+static struct phy_driver et1011c_driver[] = { {
+	.phy_id		= 0x0282f014,
+	.name		= "ET1011C",
+	.phy_id_mask	= 0xfffffff0,
+	/* PHY_GBIT_FEATURES */
+	.config_aneg	= et1011c_config_aneg,
+	.read_status	= et1011c_read_status,
+} };
+
+module_phy_driver(et1011c_driver);
+
+static const struct mdio_device_id __maybe_unused et1011c_tbl[] = {
+	{ 0x0282f014, 0xfffffff0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(mdio, et1011c_tbl);