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, 133 insertions, 0 deletions

diff --git a/drivers/parisc/asp.c b/drivers/parisc/asp.c
new file mode 100644
index 000000000..32af8f095
--- /dev/null
+++ b/drivers/parisc/asp.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	ASP Device Driver
+ *
+ *	(c) Copyright 2000 The Puffin Group Inc.
+ *
+ *	(c) 2000-2023 by Helge Deller <deller@gmx.de>
+ */
+
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <asm/io.h>
+#include <asm/led.h>
+
+#include "gsc.h"
+
+#define ASP_GSC_IRQ	3		/* hardcoded interrupt for GSC */
+
+#define ASP_VER_OFFSET 	0x20		/* offset of ASP version */
+
+#define ASP_LED_ADDR	0xf0800020
+
+#define VIPER_INT_WORD  0xFFFBF088      /* addr of viper interrupt word */
+
+static struct gsc_asic asp;
+
+static void asp_choose_irq(struct parisc_device *dev, void *ctrl)
+{
+	int irq;
+
+	switch (dev->id.sversion) {
+	case 0x71:	irq =  9; break; /* SCSI */
+	case 0x72:	irq =  8; break; /* LAN */
+	case 0x73:	irq =  1; break; /* HIL */
+	case 0x74:	irq =  7; break; /* Centronics */
+	case 0x75:	irq = (dev->hw_path == 4) ? 5 : 6; break; /* RS232 */
+	case 0x76:	irq = 10; break; /* EISA BA */
+	case 0x77:	irq = 11; break; /* Graphics1 */
+	case 0x7a:	irq = 13; break; /* Audio (Bushmaster) */
+	case 0x7b:	irq = 13; break; /* Audio (Scorpio) */
+	case 0x7c:	irq =  3; break; /* FW SCSI */
+	case 0x7d:	irq =  4; break; /* FDDI */
+	case 0x7f:	irq = 13; break; /* Audio (Outfield) */
+	default:	return;		 /* Unknown */
+	}
+
+	gsc_asic_assign_irq(ctrl, irq, &dev->irq);
+
+	switch (dev->id.sversion) {
+	case 0x73:	irq =  2; break; /* i8042 High-priority */
+	case 0x76:	irq =  0; break; /* EISA BA */
+	default:	return;		 /* Other */
+	}
+
+	gsc_asic_assign_irq(ctrl, irq, &dev->aux_irq);
+}
+
+/* There are two register ranges we're interested in.  Interrupt /
+ * Status / LED are at 0xf080xxxx and Asp special registers are at
+ * 0xf082fxxx.  PDC only tells us that Asp is at 0xf082f000, so for
+ * the purposes of interrupt handling, we have to tell other bits of
+ * the kernel to look at the other registers.
+ */
+#define ASP_INTERRUPT_ADDR 0xf0800000
+
+static int __init asp_init_chip(struct parisc_device *dev)
+{
+	struct gsc_irq gsc_irq;
+	int ret;
+
+	asp.version = gsc_readb(dev->hpa.start + ASP_VER_OFFSET) & 0xf;
+	asp.name = (asp.version == 1) ? "Asp" : "Cutoff";
+	asp.hpa = ASP_INTERRUPT_ADDR;
+
+	printk(KERN_INFO "%s version %d at 0x%lx found.\n", 
+		asp.name, asp.version, (unsigned long)dev->hpa.start);
+
+	/* the IRQ ASP should use */
+	ret = -EBUSY;
+	dev->irq = gsc_claim_irq(&gsc_irq, ASP_GSC_IRQ);
+	if (dev->irq < 0) {
+		printk(KERN_ERR "%s(): cannot get GSC irq\n", __func__);
+		goto out;
+	}
+
+	asp.eim = ((u32) gsc_irq.txn_addr) | gsc_irq.txn_data;
+
+	ret = request_irq(gsc_irq.irq, gsc_asic_intr, 0, "asp", &asp);
+	if (ret < 0)
+		goto out;
+
+	/* Program VIPER to interrupt on the ASP irq */
+	gsc_writel((1 << (31 - ASP_GSC_IRQ)),VIPER_INT_WORD);
+
+	/* Done init'ing, register this driver */
+	ret = gsc_common_setup(dev, &asp);
+	if (ret)
+		goto out;
+
+	gsc_fixup_irqs(dev, &asp, asp_choose_irq);
+	/* Mongoose is a sibling of Asp, not a child... */
+	gsc_fixup_irqs(parisc_parent(dev), &asp, asp_choose_irq);
+
+	/* initialize the chassis LEDs */ 
+#ifdef CONFIG_CHASSIS_LCD_LED	
+	register_led_driver(DISPLAY_MODEL_OLD_ASP, LED_CMD_REG_NONE, 
+		    ASP_LED_ADDR);
+#endif
+
+ out:
+	return ret;
+}
+
+static const struct parisc_device_id asp_tbl[] __initconst = {
+	{ HPHW_BA, HVERSION_REV_ANY_ID, HVERSION_ANY_ID, 0x00070 },
+	{ 0, }
+};
+MODULE_DEVICE_TABLE(parisc, asp_tbl);
+
+static struct parisc_driver asp_driver __refdata = {
+	.name =		"asp",
+	.id_table =	asp_tbl,
+	.probe =	asp_init_chip,
+};
+
+static int __init asp_init(void)
+{
+	return register_parisc_driver(&asp_driver);
+}
+arch_initcall(asp_init);