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, 288 insertions, 0 deletions

diff --git a/drivers/video/fbdev/sbuslib.c b/drivers/video/fbdev/sbuslib.c
new file mode 100644
index 000000000..dd2002d08
--- /dev/null
+++ b/drivers/video/fbdev/sbuslib.c
@@ -0,0 +1,288 @@
+// SPDX-License-Identifier: GPL-2.0
+/* sbuslib.c: Helper library for SBUS framebuffer drivers.
+ *
+ * Copyright (C) 2003 David S. Miller (davem@redhat.com)
+ */
+
+#include <linux/compat.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/fb.h>
+#include <linux/mm.h>
+#include <linux/uaccess.h>
+#include <linux/of.h>
+
+#include <asm/fbio.h>
+
+#include "sbuslib.h"
+
+void sbusfb_fill_var(struct fb_var_screeninfo *var, struct device_node *dp,
+		     int bpp)
+{
+	memset(var, 0, sizeof(*var));
+
+	var->xres = of_getintprop_default(dp, "width", 1152);
+	var->yres = of_getintprop_default(dp, "height", 900);
+	var->xres_virtual = var->xres;
+	var->yres_virtual = var->yres;
+	var->bits_per_pixel = bpp;
+}
+
+EXPORT_SYMBOL(sbusfb_fill_var);
+
+static unsigned long sbusfb_mmapsize(long size, unsigned long fbsize)
+{
+	if (size == SBUS_MMAP_EMPTY) return 0;
+	if (size >= 0) return size;
+	return fbsize * (-size);
+}
+
+int sbusfb_mmap_helper(const struct sbus_mmap_map *map,
+		       unsigned long physbase,
+		       unsigned long fbsize,
+		       unsigned long iospace,
+		       struct vm_area_struct *vma)
+{
+	unsigned int size, page, r, map_size;
+	unsigned long map_offset = 0;
+	unsigned long off;
+	int i;
+
+	if (!(vma->vm_flags & (VM_SHARED | VM_MAYSHARE)))
+		return -EINVAL;
+
+	size = vma->vm_end - vma->vm_start;
+	if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
+		return -EINVAL;
+
+	off = vma->vm_pgoff << PAGE_SHIFT;
+
+	/* VM_IO | VM_DONTEXPAND | VM_DONTDUMP are set by remap_pfn_range() */
+
+	vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+	/* Each page, see which map applies */
+	for (page = 0; page < size; ){
+		map_size = 0;
+		for (i = 0; map[i].size; i++)
+			if (map[i].voff == off+page) {
+				map_size = sbusfb_mmapsize(map[i].size, fbsize);
+#ifdef __sparc_v9__
+#define POFF_MASK	(PAGE_MASK|0x1UL)
+#else
+#define POFF_MASK	(PAGE_MASK)
+#endif
+				map_offset = (physbase + map[i].poff) & POFF_MASK;
+				break;
+			}
+		if (!map_size) {
+			page += PAGE_SIZE;
+			continue;
+		}
+		if (page + map_size > size)
+			map_size = size - page;
+		r = io_remap_pfn_range(vma,
+					vma->vm_start + page,
+					MK_IOSPACE_PFN(iospace,
+						map_offset >> PAGE_SHIFT),
+					map_size,
+					vma->vm_page_prot);
+		if (r)
+			return -EAGAIN;
+		page += map_size;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(sbusfb_mmap_helper);
+
+int sbusfb_ioctl_helper(unsigned long cmd, unsigned long arg,
+			struct fb_info *info,
+			int type, int fb_depth, unsigned long fb_size)
+{
+	switch(cmd) {
+	case FBIOGTYPE: {
+		struct fbtype __user *f = (struct fbtype __user *) arg;
+
+		if (put_user(type, &f->fb_type) ||
+		    put_user(info->var.yres, &f->fb_height) ||
+		    put_user(info->var.xres, &f->fb_width) ||
+		    put_user(fb_depth, &f->fb_depth) ||
+		    put_user(0, &f->fb_cmsize) ||
+		    put_user(fb_size, &f->fb_cmsize))
+			return -EFAULT;
+		return 0;
+	}
+	case FBIOPUTCMAP_SPARC: {
+		struct fbcmap __user *c = (struct fbcmap __user *) arg;
+		struct fb_cmap cmap;
+		u16 red, green, blue;
+		u8 red8, green8, blue8;
+		unsigned char __user *ured;
+		unsigned char __user *ugreen;
+		unsigned char __user *ublue;
+		unsigned int index, count, i;
+
+		if (get_user(index, &c->index) ||
+		    get_user(count, &c->count) ||
+		    get_user(ured, &c->red) ||
+		    get_user(ugreen, &c->green) ||
+		    get_user(ublue, &c->blue))
+			return -EFAULT;
+
+		cmap.len = 1;
+		cmap.red = &red;
+		cmap.green = &green;
+		cmap.blue = &blue;
+		cmap.transp = NULL;
+		for (i = 0; i < count; i++) {
+			int err;
+
+			if (get_user(red8, &ured[i]) ||
+			    get_user(green8, &ugreen[i]) ||
+			    get_user(blue8, &ublue[i]))
+				return -EFAULT;
+
+			red = red8 << 8;
+			green = green8 << 8;
+			blue = blue8 << 8;
+
+			cmap.start = index + i;
+			err = fb_set_cmap(&cmap, info);
+			if (err)
+				return err;
+		}
+		return 0;
+	}
+	case FBIOGETCMAP_SPARC: {
+		struct fbcmap __user *c = (struct fbcmap __user *) arg;
+		unsigned char __user *ured;
+		unsigned char __user *ugreen;
+		unsigned char __user *ublue;
+		struct fb_cmap *cmap = &info->cmap;
+		unsigned int index, count, i;
+		u8 red, green, blue;
+
+		if (get_user(index, &c->index) ||
+		    get_user(count, &c->count) ||
+		    get_user(ured, &c->red) ||
+		    get_user(ugreen, &c->green) ||
+		    get_user(ublue, &c->blue))
+			return -EFAULT;
+
+		if (index > cmap->len || count > cmap->len - index)
+			return -EINVAL;
+
+		for (i = 0; i < count; i++) {
+			red = cmap->red[index + i] >> 8;
+			green = cmap->green[index + i] >> 8;
+			blue = cmap->blue[index + i] >> 8;
+			if (put_user(red, &ured[i]) ||
+			    put_user(green, &ugreen[i]) ||
+			    put_user(blue, &ublue[i]))
+				return -EFAULT;
+		}
+		return 0;
+	}
+	default:
+		return -EINVAL;
+	}
+}
+EXPORT_SYMBOL(sbusfb_ioctl_helper);
+
+#ifdef CONFIG_COMPAT
+int sbusfb_compat_ioctl(struct fb_info *info, unsigned int cmd, unsigned long arg)
+{
+	switch (cmd) {
+	case FBIOGTYPE:
+	case FBIOSATTR:
+	case FBIOGATTR:
+	case FBIOSVIDEO:
+	case FBIOGVIDEO:
+	case FBIOSCURSOR32:
+	case FBIOGCURSOR32:	/* This is not implemented yet.
+				   Later it should be converted... */
+	case FBIOSCURPOS:
+	case FBIOGCURPOS:
+	case FBIOGCURMAX:
+		return info->fbops->fb_ioctl(info, cmd, arg);
+	case FBIOPUTCMAP32:
+	case FBIOPUTCMAP_SPARC: {
+		struct fbcmap32 c;
+		struct fb_cmap cmap;
+		u16 red, green, blue;
+		u8 red8, green8, blue8;
+		unsigned char __user *ured;
+		unsigned char __user *ugreen;
+		unsigned char __user *ublue;
+		unsigned int i;
+
+		if (copy_from_user(&c, compat_ptr(arg), sizeof(c)))
+			return -EFAULT;
+		ured = compat_ptr(c.red);
+		ugreen = compat_ptr(c.green);
+		ublue = compat_ptr(c.blue);
+
+		cmap.len = 1;
+		cmap.red = &red;
+		cmap.green = &green;
+		cmap.blue = &blue;
+		cmap.transp = NULL;
+		for (i = 0; i < c.count; i++) {
+			int err;
+
+			if (get_user(red8, &ured[i]) ||
+			    get_user(green8, &ugreen[i]) ||
+			    get_user(blue8, &ublue[i]))
+				return -EFAULT;
+
+			red = red8 << 8;
+			green = green8 << 8;
+			blue = blue8 << 8;
+
+			cmap.start = c.index + i;
+			err = fb_set_cmap(&cmap, info);
+			if (err)
+				return err;
+		}
+		return 0;
+	}
+	case FBIOGETCMAP32: {
+		struct fbcmap32 c;
+		unsigned char __user *ured;
+		unsigned char __user *ugreen;
+		unsigned char __user *ublue;
+		struct fb_cmap *cmap = &info->cmap;
+		unsigned int index, i;
+		u8 red, green, blue;
+
+		if (copy_from_user(&c, compat_ptr(arg), sizeof(c)))
+			return -EFAULT;
+		index = c.index;
+		ured = compat_ptr(c.red);
+		ugreen = compat_ptr(c.green);
+		ublue = compat_ptr(c.blue);
+
+		if (index > cmap->len || c.count > cmap->len - index)
+			return -EINVAL;
+
+		for (i = 0; i < c.count; i++) {
+			red = cmap->red[index + i] >> 8;
+			green = cmap->green[index + i] >> 8;
+			blue = cmap->blue[index + i] >> 8;
+			if (put_user(red, &ured[i]) ||
+			    put_user(green, &ugreen[i]) ||
+			    put_user(blue, &ublue[i]))
+				return -EFAULT;
+		}
+		return 0;
+	}
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+EXPORT_SYMBOL(sbusfb_compat_ioctl);
+#endif