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, 154 insertions, 0 deletions

diff --git a/arch/m68k/coldfire/nettel.c b/arch/m68k/coldfire/nettel.c
new file mode 100644
index 000000000..e304571e0
--- /dev/null
+++ b/arch/m68k/coldfire/nettel.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+/***************************************************************************/
+
+/*
+ *	nettel.c -- startup code support for the NETtel boards
+ *
+ *	Copyright (C) 2009, Greg Ungerer (gerg@snapgear.com)
+ */
+
+/***************************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/param.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <asm/coldfire.h>
+#include <asm/mcfsim.h>
+#include <asm/nettel.h>
+
+/***************************************************************************/
+
+/*
+ * Define the IO and interrupt resources of the 2 SMC9196 interfaces.
+ */
+#define	NETTEL_SMC0_ADDR	0x30600300
+#define	NETTEL_SMC0_IRQ		29
+
+#define	NETTEL_SMC1_ADDR	0x30600000
+#define	NETTEL_SMC1_IRQ		27
+
+/*
+ * We need some access into the SMC9196 registers. Define those registers
+ * we will need here (including the smc91x.h doesn't seem to give us these
+ * in a simple form).
+ */
+#define	SMC91xx_BANKSELECT	14
+#define	SMC91xx_BASEADDR	2
+#define	SMC91xx_BASEMAC		4
+
+/***************************************************************************/
+
+static struct resource nettel_smc91x_0_resources[] = {
+	{
+		.start		= NETTEL_SMC0_ADDR,
+		.end		= NETTEL_SMC0_ADDR + 0x20,
+		.flags		= IORESOURCE_MEM,
+	},
+	{
+		.start		= NETTEL_SMC0_IRQ,
+		.end		= NETTEL_SMC0_IRQ,
+		.flags		= IORESOURCE_IRQ,
+	},
+};
+
+static struct resource nettel_smc91x_1_resources[] = {
+	{
+		.start		= NETTEL_SMC1_ADDR,
+		.end		= NETTEL_SMC1_ADDR + 0x20,
+		.flags		= IORESOURCE_MEM,
+	},
+	{
+		.start		= NETTEL_SMC1_IRQ,
+		.end		= NETTEL_SMC1_IRQ,
+		.flags		= IORESOURCE_IRQ,
+	},
+};
+
+static struct platform_device nettel_smc91x[] = {
+	{
+		.name			= "smc91x",
+		.id			= 0,
+		.num_resources		= ARRAY_SIZE(nettel_smc91x_0_resources),
+		.resource		= nettel_smc91x_0_resources,
+	},
+	{
+		.name			= "smc91x",
+		.id			= 1,
+		.num_resources		= ARRAY_SIZE(nettel_smc91x_1_resources),
+		.resource		= nettel_smc91x_1_resources,
+	},
+};
+
+static struct platform_device *nettel_devices[] __initdata = {
+	&nettel_smc91x[0],
+	&nettel_smc91x[1],
+};
+
+/***************************************************************************/
+
+static u8 nettel_macdefault[] __initdata = {
+	0x00, 0xd0, 0xcf, 0x00, 0x00, 0x01,
+};
+
+/*
+ * Set flash contained MAC address into SMC9196 core. Make sure the flash
+ * MAC address is sane, and not an empty flash. If no good use the Moreton
+ * Bay default MAC address instead.
+ */
+
+static void __init nettel_smc91x_setmac(unsigned int ioaddr, unsigned int flashaddr)
+{
+	u16 *macp;
+
+	macp = (u16 *) flashaddr;
+	if ((macp[0] == 0xffff) && (macp[1] == 0xffff) && (macp[2] == 0xffff))
+		macp = (u16 *) &nettel_macdefault[0];
+
+	mcf_write16(1, NETTEL_SMC0_ADDR + SMC91xx_BANKSELECT);
+	mcf_write16(macp[0], ioaddr + SMC91xx_BASEMAC);
+	mcf_write16(macp[1], ioaddr + SMC91xx_BASEMAC + 2);
+	mcf_write16(macp[2], ioaddr + SMC91xx_BASEMAC + 4);
+}
+
+/***************************************************************************/
+
+/*
+ * Re-map the address space of at least one of the SMC ethernet
+ * parts. Both parts power up decoding the same address, so we
+ * need to move one of them first, before doing anything else.
+ */
+
+static void __init nettel_smc91x_init(void)
+{
+	mcf_write16(0x00ec, MCFSIM_PADDR);
+	mcf_setppdata(0, 0x0080);
+	mcf_write16(1, NETTEL_SMC0_ADDR + SMC91xx_BANKSELECT);
+	mcf_write16(0x0067, NETTEL_SMC0_ADDR + SMC91xx_BASEADDR);
+	mcf_setppdata(0x0080, 0);
+
+	/* Set correct chip select timing for SMC9196 accesses */
+	mcf_write16(0x1180, MCFSIM_CSCR3);
+
+	/* Set the SMC interrupts to be auto-vectored */
+	mcf_autovector(NETTEL_SMC0_IRQ);
+	mcf_autovector(NETTEL_SMC1_IRQ);
+
+	/* Set MAC addresses from flash for both interfaces */
+	nettel_smc91x_setmac(NETTEL_SMC0_ADDR, 0xf0006000);
+	nettel_smc91x_setmac(NETTEL_SMC1_ADDR, 0xf0006006);
+}
+
+/***************************************************************************/
+
+static int __init init_nettel(void)
+{
+	nettel_smc91x_init();
+	platform_add_devices(nettel_devices, ARRAY_SIZE(nettel_devices));
+	return 0;
+}
+
+arch_initcall(init_nettel);
+
+/***************************************************************************/