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, 242 insertions, 0 deletions

diff --git a/drivers/scsi/sim710.c b/drivers/scsi/sim710.c
new file mode 100644
index 000000000..408f37003
--- /dev/null
+++ b/drivers/scsi/sim710.c
@@ -0,0 +1,242 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * sim710.c - Copyright (C) 1999 Richard Hirst <richard@sleepie.demon.co.uk>
+ *
+ *----------------------------------------------------------------------------
+ *----------------------------------------------------------------------------
+ *
+ * MCA card detection code by Trent McNair. (now deleted)
+ * Fixes to not explicitly nul bss data from Xavier Bestel.
+ * Some multiboard fixes from Rolf Eike Beer.
+ * Auto probing of EISA config space from Trevor Hemsley.
+ *
+ * Rewritten to use 53c700.c by James.Bottomley@SteelEye.com
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include <linux/blkdev.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/eisa.h>
+#include <linux/interrupt.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_transport.h>
+#include <scsi/scsi_transport_spi.h>
+
+#include "53c700.h"
+
+
+/* Must be enough for EISA */
+#define MAX_SLOTS 8
+static __u8 __initdata id_array[MAX_SLOTS] = { [0 ... MAX_SLOTS-1] = 7 };
+
+static char *sim710;		/* command line passed by insmod */
+
+MODULE_AUTHOR("Richard Hirst");
+MODULE_DESCRIPTION("Simple NCR53C710 driver");
+MODULE_LICENSE("GPL");
+
+module_param(sim710, charp, 0);
+
+#ifdef MODULE
+#define ARG_SEP ' '
+#else
+#define ARG_SEP ','
+#endif
+
+static __init int
+param_setup(char *str)
+{
+	char *pos = str, *next;
+	int slot = -1;
+
+	while(pos != NULL && (next = strchr(pos, ':')) != NULL) {
+		int val = (int)simple_strtoul(++next, NULL, 0);
+
+		if(!strncmp(pos, "slot:", 5))
+			slot = val;
+		else if(!strncmp(pos, "id:", 3)) {
+			if(slot == -1) {
+				printk(KERN_WARNING "sim710: Must specify slot for id parameter\n");
+			} else if(slot >= MAX_SLOTS) {
+				printk(KERN_WARNING "sim710: Illegal slot %d for id %d\n", slot, val);
+			} else {
+				id_array[slot] = val;
+			}
+		}
+		if((pos = strchr(pos, ARG_SEP)) != NULL)
+			pos++;
+	}
+	return 1;
+}
+__setup("sim710=", param_setup);
+
+static struct scsi_host_template sim710_driver_template = {
+	.name			= "LSI (Symbios) 710 EISA",
+	.proc_name		= "sim710",
+	.this_id		= 7,
+	.module			= THIS_MODULE,
+};
+
+static int sim710_probe_common(struct device *dev, unsigned long base_addr,
+			       int irq, int clock, int differential,
+			       int scsi_id)
+{
+	struct Scsi_Host * host = NULL;
+	struct NCR_700_Host_Parameters *hostdata =
+		kzalloc_obj(struct NCR_700_Host_Parameters);
+
+	printk(KERN_NOTICE "sim710: %s\n", dev_name(dev));
+	printk(KERN_NOTICE "sim710: irq = %d, clock = %d, base = 0x%lx, scsi_id = %d\n",
+	       irq, clock, base_addr, scsi_id);
+
+	if(hostdata == NULL) {
+		printk(KERN_ERR "sim710: Failed to allocate host data\n");
+		goto out;
+	}
+
+	if(request_region(base_addr, 64, "sim710") == NULL) {
+		printk(KERN_ERR "sim710: Failed to reserve IO region 0x%lx\n",
+		       base_addr);
+		goto out_free;
+	}
+
+	/* Fill in the three required pieces of hostdata */
+	hostdata->base = ioport_map(base_addr, 64);
+	hostdata->differential = differential;
+	hostdata->clock = clock;
+	hostdata->chip710 = 1;
+	hostdata->burst_length = 8;
+
+	/* and register the chip */
+	if((host = NCR_700_detect(&sim710_driver_template, hostdata, dev))
+	   == NULL) {
+		printk(KERN_ERR "sim710: No host detected; card configuration problem?\n");
+		goto out_release;
+	}
+	host->this_id = scsi_id;
+	host->base = base_addr;
+	host->irq = irq;
+	if (request_irq(irq, NCR_700_intr, IRQF_SHARED, "sim710", host)) {
+		printk(KERN_ERR "sim710: request_irq failed\n");
+		goto out_put_host;
+	}
+
+	dev_set_drvdata(dev, host);
+	scsi_scan_host(host);
+
+	return 0;
+
+ out_put_host:
+	scsi_host_put(host);
+ out_release:
+	ioport_unmap(hostdata->base);
+	release_region(base_addr, 64);
+ out_free:
+	kfree(hostdata);
+ out:
+	return -ENODEV;
+}
+
+static int sim710_device_remove(struct device *dev)
+{
+	struct Scsi_Host *host = dev_get_drvdata(dev);
+	struct NCR_700_Host_Parameters *hostdata =
+		(struct NCR_700_Host_Parameters *)host->hostdata[0];
+
+	scsi_remove_host(host);
+	NCR_700_release(host);
+	ioport_unmap(hostdata->base);
+	kfree(hostdata);
+	free_irq(host->irq, host);
+	release_region(host->base, 64);
+	return 0;
+}
+
+#ifdef CONFIG_EISA
+static struct eisa_device_id sim710_eisa_ids[] = {
+	{ "CPQ4410" },
+	{ "CPQ4411" },
+	{ "HWP0C80" },
+	{ "" }
+};
+MODULE_DEVICE_TABLE(eisa, sim710_eisa_ids);
+
+static int sim710_eisa_probe(struct device *dev)
+{
+	struct eisa_device *edev = to_eisa_device(dev);
+	unsigned long io_addr = edev->base_addr;
+	char eisa_cpq_irqs[] = { 11, 14, 15, 10, 9, 0 };
+	char eisa_hwp_irqs[] = { 3, 4, 5, 7, 12, 10, 11, 0};
+	char *eisa_irqs;
+	unsigned char irq_index;
+	unsigned char irq, differential = 0, scsi_id = 7;
+
+	if(strcmp(edev->id.sig, "HWP0C80") == 0) {
+		__u8 val;
+		eisa_irqs =  eisa_hwp_irqs;
+		irq_index = (inb(io_addr + 0xc85) & 0x7) - 1;
+
+		val = inb(io_addr + 0x4);
+		scsi_id = ffs(val) - 1;
+
+		if(scsi_id > 7 || (val & ~(1<<scsi_id)) != 0) {
+			printk(KERN_ERR "sim710.c, EISA card %s has incorrect scsi_id, setting to 7\n", dev_name(dev));
+			scsi_id = 7;
+		}
+	} else {
+		eisa_irqs = eisa_cpq_irqs;
+		irq_index = inb(io_addr + 0xc88) & 0x07;
+	}
+
+	if(irq_index >= strlen(eisa_irqs)) {
+		printk("sim710.c: irq nasty\n");
+		return -ENODEV;
+	}
+
+	irq = eisa_irqs[irq_index];
+		
+	return sim710_probe_common(dev, io_addr, irq, 50,
+				   differential, scsi_id);
+}
+
+static struct eisa_driver sim710_eisa_driver = {
+	.id_table		= sim710_eisa_ids,
+	.driver = {
+		.name		= "sim710",
+		.probe		= sim710_eisa_probe,
+		.remove		= sim710_device_remove,
+	},
+};
+#endif /* CONFIG_EISA */
+
+static int __init sim710_init(void)
+{
+#ifdef MODULE
+	if (sim710)
+		param_setup(sim710);
+#endif
+
+#ifdef CONFIG_EISA
+	/*
+	 * FIXME: We'd really like to return -ENODEV if no devices have actually
+	 * been found.  However eisa_driver_register() only reports problems
+	 * with kobject_register() so simply return success for now.
+	 */
+	eisa_driver_register(&sim710_eisa_driver);
+#endif
+	return 0;
+}
+
+static void __exit sim710_exit(void)
+{
+#ifdef CONFIG_EISA
+	eisa_driver_unregister(&sim710_eisa_driver);
+#endif
+}
+
+module_init(sim710_init);
+module_exit(sim710_exit);