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, 250 insertions, 0 deletions

diff --git a/drivers/video/fbdev/sunxvr2500.c b/drivers/video/fbdev/sunxvr2500.c
new file mode 100644
index 000000000..b7587ff4d
--- /dev/null
+++ b/drivers/video/fbdev/sunxvr2500.c
@@ -0,0 +1,250 @@
+/* sunxvr2500.c: Sun 3DLABS XVR-2500 et al. fb driver for sparc64 systems
+ *
+ * License: GPL
+ *
+ * Copyright (C) 2007 David S. Miller (davem@davemloft.net)
+ */
+
+#include <linux/aperture.h>
+#include <linux/kernel.h>
+#include <linux/fb.h>
+#include <linux/pci.h>
+#include <linux/init.h>
+#include <linux/of.h>
+
+#include <asm/io.h>
+
+struct s3d_info {
+	struct fb_info		*info;
+	struct pci_dev		*pdev;
+
+	char __iomem		*fb_base;
+	unsigned long		fb_base_phys;
+
+	struct device_node	*of_node;
+
+	unsigned int		width;
+	unsigned int		height;
+	unsigned int		depth;
+	unsigned int		fb_size;
+
+	u32			pseudo_palette[16];
+};
+
+static int s3d_get_props(struct s3d_info *sp)
+{
+	sp->width = of_getintprop_default(sp->of_node, "width", 0);
+	sp->height = of_getintprop_default(sp->of_node, "height", 0);
+	sp->depth = of_getintprop_default(sp->of_node, "depth", 8);
+
+	if (!sp->width || !sp->height) {
+		pci_err(sp->pdev, "Critical properties missing\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int s3d_setcolreg(unsigned regno,
+			 unsigned red, unsigned green, unsigned blue,
+			 unsigned transp, struct fb_info *info)
+{
+	u32 value;
+
+	if (regno < 16) {
+		red >>= 8;
+		green >>= 8;
+		blue >>= 8;
+
+		value = (blue << 24) | (green << 16) | (red << 8);
+		((u32 *)info->pseudo_palette)[regno] = value;
+	}
+
+	return 0;
+}
+
+static const struct fb_ops s3d_ops = {
+	.owner			= THIS_MODULE,
+	FB_DEFAULT_IOMEM_OPS,
+	.fb_setcolreg		= s3d_setcolreg,
+};
+
+static int s3d_set_fbinfo(struct s3d_info *sp)
+{
+	struct fb_info *info = sp->info;
+	struct fb_var_screeninfo *var = &info->var;
+
+	info->fbops = &s3d_ops;
+	info->screen_base = sp->fb_base;
+	info->screen_size = sp->fb_size;
+
+	info->pseudo_palette = sp->pseudo_palette;
+
+	/* Fill fix common fields */
+	strscpy(info->fix.id, "s3d", sizeof(info->fix.id));
+        info->fix.smem_start = sp->fb_base_phys;
+        info->fix.smem_len = sp->fb_size;
+        info->fix.type = FB_TYPE_PACKED_PIXELS;
+	if (sp->depth == 32 || sp->depth == 24)
+		info->fix.visual = FB_VISUAL_TRUECOLOR;
+	else
+		info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
+
+	var->xres = sp->width;
+	var->yres = sp->height;
+	var->xres_virtual = var->xres;
+	var->yres_virtual = var->yres;
+	var->bits_per_pixel = sp->depth;
+
+	var->red.offset = 8;
+	var->red.length = 8;
+	var->green.offset = 16;
+	var->green.length = 8;
+	var->blue.offset = 24;
+	var->blue.length = 8;
+	var->transp.offset = 0;
+	var->transp.length = 0;
+
+	if (fb_alloc_cmap(&info->cmap, 256, 0)) {
+		pci_err(sp->pdev, "Cannot allocate color map\n");
+		return -ENOMEM;
+	}
+
+        return 0;
+}
+
+static int s3d_pci_register(struct pci_dev *pdev,
+			    const struct pci_device_id *ent)
+{
+	struct fb_info *info;
+	struct s3d_info *sp;
+	int err;
+
+	err = aperture_remove_conflicting_pci_devices(pdev, "s3dfb");
+	if (err)
+		return err;
+
+	err = pci_enable_device(pdev);
+	if (err < 0) {
+		pci_err(pdev, "Cannot enable PCI device\n");
+		goto err_out;
+	}
+
+	info = framebuffer_alloc(sizeof(struct s3d_info), &pdev->dev);
+	if (!info) {
+		err = -ENOMEM;
+		goto err_disable;
+	}
+
+	sp = info->par;
+	sp->info = info;
+	sp->pdev = pdev;
+	sp->of_node = pci_device_to_OF_node(pdev);
+	if (!sp->of_node) {
+		pci_err(pdev, "Cannot find OF node\n");
+		err = -ENODEV;
+		goto err_release_fb;
+	}
+
+	sp->fb_base_phys = pci_resource_start (pdev, 1);
+
+	err = pci_request_region(pdev, 1, "s3d framebuffer");
+	if (err < 0) {
+		pci_err(pdev, "Cannot request region 1\n");
+		goto err_release_fb;
+	}
+
+	err = s3d_get_props(sp);
+	if (err)
+		goto err_release_pci;
+
+	/* XXX 'linebytes' is often wrong, it is equal to the width
+	 * XXX with depth of 32 on my XVR-2500 which is clearly not
+	 * XXX right.  So we don't try to use it.
+	 */
+	switch (sp->depth) {
+	case 8:
+		info->fix.line_length = sp->width;
+		break;
+	case 16:
+		info->fix.line_length = sp->width * 2;
+		break;
+	case 24:
+		info->fix.line_length = sp->width * 3;
+		break;
+	case 32:
+		info->fix.line_length = sp->width * 4;
+		break;
+	}
+	sp->fb_size = info->fix.line_length * sp->height;
+
+	sp->fb_base = ioremap(sp->fb_base_phys, sp->fb_size);
+	if (!sp->fb_base) {
+		err = -ENOMEM;
+		goto err_release_pci;
+	}
+
+	err = s3d_set_fbinfo(sp);
+	if (err)
+		goto err_unmap_fb;
+
+	pci_set_drvdata(pdev, info);
+
+	pci_info(pdev, "Found device\n");
+
+	err = register_framebuffer(info);
+	if (err < 0) {
+		pci_err(pdev, "Could not register framebuffer\n");
+		goto err_unmap_fb;
+	}
+
+	return 0;
+
+err_unmap_fb:
+	iounmap(sp->fb_base);
+
+err_release_pci:
+	pci_release_region(pdev, 1);
+
+err_release_fb:
+        framebuffer_release(info);
+
+err_disable:
+	pci_disable_device(pdev);
+
+err_out:
+	return err;
+}
+
+static const struct pci_device_id s3d_pci_table[] = {
+	{	PCI_DEVICE(PCI_VENDOR_ID_3DLABS, 0x002c),	},
+	{	PCI_DEVICE(PCI_VENDOR_ID_3DLABS, 0x002d),	},
+	{	PCI_DEVICE(PCI_VENDOR_ID_3DLABS, 0x002e),	},
+	{	PCI_DEVICE(PCI_VENDOR_ID_3DLABS, 0x002f),	},
+	{	PCI_DEVICE(PCI_VENDOR_ID_3DLABS, 0x0030),	},
+	{	PCI_DEVICE(PCI_VENDOR_ID_3DLABS, 0x0031),	},
+	{	PCI_DEVICE(PCI_VENDOR_ID_3DLABS, 0x0032),	},
+	{	PCI_DEVICE(PCI_VENDOR_ID_3DLABS, 0x0033),	},
+	{ 0, }
+};
+
+static struct pci_driver s3d_driver = {
+	.driver = {
+		.suppress_bind_attrs = true,
+	},
+	.name		= "s3d",
+	.id_table	= s3d_pci_table,
+	.probe		= s3d_pci_register,
+};
+
+static int __init s3d_init(void)
+{
+	if (fb_modesetting_disabled("s3d"))
+		return -ENODEV;
+
+	if (fb_get_options("s3d", NULL))
+		return -ENODEV;
+
+	return pci_register_driver(&s3d_driver);
+}
+device_initcall(s3d_init);