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, 189 insertions, 0 deletions

diff --git a/arch/m68k/68000/ints.c b/arch/m68k/68000/ints.c
new file mode 100644
index 000000000..2ba9926e9
--- /dev/null
+++ b/arch/m68k/68000/ints.c
@@ -0,0 +1,189 @@
+/*
+ * ints.c - Generic interrupt controller support
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive
+ * for more details.
+ *
+ * Copyright 1996 Roman Zippel
+ * Copyright 1999 D. Jeff Dionne <jeff@rt-control.com>
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/cpu.h>
+#include <asm/traps.h>
+#include <asm/io.h>
+#include <asm/machdep.h>
+
+#if defined(CONFIG_M68EZ328)
+#include <asm/MC68EZ328.h>
+#elif defined(CONFIG_M68VZ328)
+#include <asm/MC68VZ328.h>
+#else
+#include <asm/MC68328.h>
+#endif
+
+#include "ints.h"
+
+/* assembler routines */
+asmlinkage void system_call(void);
+asmlinkage void buserr(void);
+asmlinkage void trap(void);
+asmlinkage void trap3(void);
+asmlinkage void trap4(void);
+asmlinkage void trap5(void);
+asmlinkage void trap6(void);
+asmlinkage void trap7(void);
+asmlinkage void trap8(void);
+asmlinkage void trap9(void);
+asmlinkage void trap10(void);
+asmlinkage void trap11(void);
+asmlinkage void trap12(void);
+asmlinkage void trap13(void);
+asmlinkage void trap14(void);
+asmlinkage void trap15(void);
+asmlinkage void trap33(void);
+asmlinkage void trap34(void);
+asmlinkage void trap35(void);
+asmlinkage void trap36(void);
+asmlinkage void trap37(void);
+asmlinkage void trap38(void);
+asmlinkage void trap39(void);
+asmlinkage void trap40(void);
+asmlinkage void trap41(void);
+asmlinkage void trap42(void);
+asmlinkage void trap43(void);
+asmlinkage void trap44(void);
+asmlinkage void trap45(void);
+asmlinkage void trap46(void);
+asmlinkage void trap47(void);
+asmlinkage irqreturn_t bad_interrupt(int, void *);
+asmlinkage irqreturn_t inthandler(void);
+asmlinkage irqreturn_t inthandler1(void);
+asmlinkage irqreturn_t inthandler2(void);
+asmlinkage irqreturn_t inthandler3(void);
+asmlinkage irqreturn_t inthandler4(void);
+asmlinkage irqreturn_t inthandler5(void);
+asmlinkage irqreturn_t inthandler6(void);
+asmlinkage irqreturn_t inthandler7(void);
+
+/* The 68k family did not have a good way to determine the source
+ * of interrupts until later in the family.  The EC000 core does
+ * not provide the vector number on the stack, we vector everything
+ * into one vector and look in the blasted mask register...
+ * This code is designed to be fast, almost constant time, not clean!
+ */
+asmlinkage void process_int(int vec, struct pt_regs *fp)
+{
+	int irq;
+	int mask;
+
+	unsigned long pend = ISR;
+
+	while (pend) {
+		if (pend & 0x0000ffff) {
+			if (pend & 0x000000ff) {
+				if (pend & 0x0000000f) {
+					mask = 0x00000001;
+					irq = 0;
+				} else {
+					mask = 0x00000010;
+					irq = 4;
+				}
+			} else {
+				if (pend & 0x00000f00) {
+					mask = 0x00000100;
+					irq = 8;
+				} else {
+					mask = 0x00001000;
+					irq = 12;
+				}
+			}
+		} else {
+			if (pend & 0x00ff0000) {
+				if (pend & 0x000f0000) {
+					mask = 0x00010000;
+					irq = 16;
+				} else {
+					mask = 0x00100000;
+					irq = 20;
+				}
+			} else {
+				if (pend & 0x0f000000) {
+					mask = 0x01000000;
+					irq = 24;
+				} else {
+					mask = 0x10000000;
+					irq = 28;
+				}
+			}
+		}
+
+		while (! (mask & pend)) {
+			mask <<=1;
+			irq++;
+		}
+
+		do_IRQ(irq, fp);
+		pend &= ~mask;
+	}
+}
+
+static void intc_irq_unmask(struct irq_data *d)
+{
+	IMR &= ~(1 << d->irq);
+}
+
+static void intc_irq_mask(struct irq_data *d)
+{
+	IMR |= (1 << d->irq);
+}
+
+static struct irq_chip intc_irq_chip = {
+	.name		= "M68K-INTC",
+	.irq_mask	= intc_irq_mask,
+	.irq_unmask	= intc_irq_unmask,
+};
+
+/*
+ * This function should be called during kernel startup to initialize
+ * the machine vector table.
+ */
+void __init trap_init(void)
+{
+	int i;
+
+	/* set up the vectors */
+	for (i = 72; i < 256; ++i)
+		_ramvec[i] = (e_vector) bad_interrupt;
+
+	_ramvec[32] = system_call;
+
+	_ramvec[65] = (e_vector) inthandler1;
+	_ramvec[66] = (e_vector) inthandler2;
+	_ramvec[67] = (e_vector) inthandler3;
+	_ramvec[68] = (e_vector) inthandler4;
+	_ramvec[69] = (e_vector) inthandler5;
+	_ramvec[70] = (e_vector) inthandler6;
+	_ramvec[71] = (e_vector) inthandler7;
+}
+
+void __init init_IRQ(void)
+{
+	int i;
+
+	IVR = 0x40; /* Set DragonBall IVR (interrupt base) to 64 */
+
+	/* turn off all interrupts */
+	IMR = ~0;
+
+	for (i = 0; (i < NR_IRQS); i++) {
+		irq_set_chip(i, &intc_irq_chip);
+		irq_set_handler(i, handle_level_irq);
+	}
+}
+