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, 209 insertions, 0 deletions

diff --git a/drivers/scsi/jazz_esp.c b/drivers/scsi/jazz_esp.c
new file mode 100644
index 000000000..35137f5cf
--- /dev/null
+++ b/drivers/scsi/jazz_esp.c
@@ -0,0 +1,209 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* jazz_esp.c: ESP front-end for MIPS JAZZ systems.
+ *
+ * Copyright (C) 2007 Thomas Bogendörfer (tsbogend@alpha.frankende)
+ */
+
+#include <linux/kernel.h>
+#include <linux/gfp.h>
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+
+#include <asm/irq.h>
+#include <asm/io.h>
+#include <asm/dma.h>
+
+#include <asm/jazz.h>
+#include <asm/jazzdma.h>
+
+#include <scsi/scsi_host.h>
+
+#include "esp_scsi.h"
+
+#define DRV_MODULE_NAME		"jazz_esp"
+#define PFX DRV_MODULE_NAME	": "
+#define DRV_VERSION		"1.000"
+#define DRV_MODULE_RELDATE	"May 19, 2007"
+
+static void jazz_esp_write8(struct esp *esp, u8 val, unsigned long reg)
+{
+	*(volatile u8 *)(esp->regs + reg) = val;
+}
+
+static u8 jazz_esp_read8(struct esp *esp, unsigned long reg)
+{
+	return *(volatile u8 *)(esp->regs + reg);
+}
+
+static int jazz_esp_irq_pending(struct esp *esp)
+{
+	if (jazz_esp_read8(esp, ESP_STATUS) & ESP_STAT_INTR)
+		return 1;
+	return 0;
+}
+
+static void jazz_esp_reset_dma(struct esp *esp)
+{
+	vdma_disable ((int)esp->dma_regs);
+}
+
+static void jazz_esp_dma_drain(struct esp *esp)
+{
+	/* nothing to do */
+}
+
+static void jazz_esp_dma_invalidate(struct esp *esp)
+{
+	vdma_disable ((int)esp->dma_regs);
+}
+
+static void jazz_esp_send_dma_cmd(struct esp *esp, u32 addr, u32 esp_count,
+				  u32 dma_count, int write, u8 cmd)
+{
+	BUG_ON(!(cmd & ESP_CMD_DMA));
+
+	jazz_esp_write8(esp, (esp_count >> 0) & 0xff, ESP_TCLOW);
+	jazz_esp_write8(esp, (esp_count >> 8) & 0xff, ESP_TCMED);
+	vdma_disable ((int)esp->dma_regs);
+	if (write)
+		vdma_set_mode ((int)esp->dma_regs, DMA_MODE_READ);
+	else
+		vdma_set_mode ((int)esp->dma_regs, DMA_MODE_WRITE);
+
+	vdma_set_addr ((int)esp->dma_regs, addr);
+	vdma_set_count ((int)esp->dma_regs, dma_count);
+	vdma_enable ((int)esp->dma_regs);
+
+	scsi_esp_cmd(esp, cmd);
+}
+
+static int jazz_esp_dma_error(struct esp *esp)
+{
+	u32 enable = vdma_get_enable((int)esp->dma_regs);
+
+	if (enable & (R4030_MEM_INTR|R4030_ADDR_INTR))
+		return 1;
+
+	return 0;
+}
+
+static const struct esp_driver_ops jazz_esp_ops = {
+	.esp_write8	=	jazz_esp_write8,
+	.esp_read8	=	jazz_esp_read8,
+	.irq_pending	=	jazz_esp_irq_pending,
+	.reset_dma	=	jazz_esp_reset_dma,
+	.dma_drain	=	jazz_esp_dma_drain,
+	.dma_invalidate	=	jazz_esp_dma_invalidate,
+	.send_dma_cmd	=	jazz_esp_send_dma_cmd,
+	.dma_error	=	jazz_esp_dma_error,
+};
+
+static int esp_jazz_probe(struct platform_device *dev)
+{
+	const struct scsi_host_template *tpnt = &scsi_esp_template;
+	struct Scsi_Host *host;
+	struct esp *esp;
+	struct resource *res;
+	int err;
+
+	host = scsi_host_alloc(tpnt, sizeof(struct esp));
+
+	err = -ENOMEM;
+	if (!host)
+		goto fail;
+
+	host->max_id = 8;
+	esp = shost_priv(host);
+
+	esp->host = host;
+	esp->dev = &dev->dev;
+	esp->ops = &jazz_esp_ops;
+
+	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+	if (!res)
+		goto fail_unlink;
+
+	esp->regs = (void __iomem *)res->start;
+	if (!esp->regs)
+		goto fail_unlink;
+
+	res = platform_get_resource(dev, IORESOURCE_MEM, 1);
+	if (!res)
+		goto fail_unlink;
+
+	esp->dma_regs = (void __iomem *)res->start;
+
+	esp->command_block = dma_alloc_coherent(esp->dev, 16,
+						&esp->command_block_dma,
+						GFP_KERNEL);
+	if (!esp->command_block)
+		goto fail_unmap_regs;
+
+	host->irq = err = platform_get_irq(dev, 0);
+	if (err < 0)
+		goto fail_unmap_command_block;
+	err = request_irq(host->irq, scsi_esp_intr, IRQF_SHARED, "ESP", esp);
+	if (err < 0)
+		goto fail_unmap_command_block;
+
+	esp->scsi_id = 7;
+	esp->host->this_id = esp->scsi_id;
+	esp->scsi_id_mask = (1 << esp->scsi_id);
+	esp->cfreq = 40000000;
+
+	dev_set_drvdata(&dev->dev, esp);
+
+	err = scsi_esp_register(esp);
+	if (err)
+		goto fail_free_irq;
+
+	return 0;
+
+fail_free_irq:
+	free_irq(host->irq, esp);
+fail_unmap_command_block:
+	dma_free_coherent(esp->dev, 16,
+			  esp->command_block,
+			  esp->command_block_dma);
+fail_unmap_regs:
+fail_unlink:
+	scsi_host_put(host);
+fail:
+	return err;
+}
+
+static void esp_jazz_remove(struct platform_device *dev)
+{
+	struct esp *esp = dev_get_drvdata(&dev->dev);
+	unsigned int irq = esp->host->irq;
+
+	scsi_esp_unregister(esp);
+
+	free_irq(irq, esp);
+	dma_free_coherent(esp->dev, 16,
+			  esp->command_block,
+			  esp->command_block_dma);
+
+	scsi_host_put(esp->host);
+}
+
+/* work with hotplug and coldplug */
+MODULE_ALIAS("platform:jazz_esp");
+
+static struct platform_driver esp_jazz_driver = {
+	.probe		= esp_jazz_probe,
+	.remove		= esp_jazz_remove,
+	.driver	= {
+		.name	= "jazz_esp",
+	},
+};
+module_platform_driver(esp_jazz_driver);
+
+MODULE_DESCRIPTION("JAZZ ESP SCSI driver");
+MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);