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, 87 insertions, 0 deletions

diff --git a/arch/m68k/coldfire/firebee.c b/arch/m68k/coldfire/firebee.c
new file mode 100644
index 000000000..3b9d4fc6f
--- /dev/null
+++ b/arch/m68k/coldfire/firebee.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0
+/***************************************************************************/
+
+/*
+ *	firebee.c -- extra startup code support for the FireBee boards
+ *
+ *	Copyright (C) 2011, Greg Ungerer (gerg@snapgear.com)
+ */
+
+/***************************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/physmap.h>
+#include <asm/coldfire.h>
+#include <asm/mcfsim.h>
+
+/***************************************************************************/
+
+/*
+ *	8MB of NOR flash fitted to the FireBee board.
+ */
+#define	FLASH_PHYS_ADDR		0xe0000000	/* Physical address of flash */
+#define	FLASH_PHYS_SIZE		0x00800000	/* Size of flash */
+
+#define	PART_BOOT_START		0x00000000	/* Start at bottom of flash */
+#define	PART_BOOT_SIZE		0x00040000	/* 256k in size */
+#define	PART_IMAGE_START	0x00040000	/* Start after boot loader */
+#define	PART_IMAGE_SIZE		0x006c0000	/* Most of flash */
+#define	PART_FPGA_START		0x00700000	/* Start at offset 7MB */
+#define	PART_FPGA_SIZE		0x00100000	/* 1MB in size */
+
+static struct mtd_partition firebee_flash_parts[] = {
+	{
+		.name	= "dBUG",
+		.offset	= PART_BOOT_START,
+		.size	= PART_BOOT_SIZE,
+	},
+	{
+		.name	= "FPGA",
+		.offset	= PART_FPGA_START,
+		.size	= PART_FPGA_SIZE,
+	},
+	{
+		.name	= "image",
+		.offset	= PART_IMAGE_START,
+		.size	= PART_IMAGE_SIZE,
+	},
+};
+
+static struct physmap_flash_data firebee_flash_data = {
+	.width		= 2,
+	.nr_parts	= ARRAY_SIZE(firebee_flash_parts),
+	.parts		= firebee_flash_parts,
+};
+
+static struct resource firebee_flash_resource = {
+	.start		= FLASH_PHYS_ADDR,
+	.end		= FLASH_PHYS_ADDR + FLASH_PHYS_SIZE,
+	.flags		= IORESOURCE_MEM,
+};
+
+static struct platform_device firebee_flash = {
+	.name		= "physmap-flash",
+	.id		= 0,
+	.dev		= {
+		.platform_data = &firebee_flash_data,
+	},
+	.num_resources	= 1,
+	.resource	= &firebee_flash_resource,
+};
+
+/***************************************************************************/
+
+static int __init init_firebee(void)
+{
+	platform_device_register(&firebee_flash);
+	return 0;
+}
+
+arch_initcall(init_firebee);
+
+/***************************************************************************/