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, 395 insertions, 0 deletions

diff --git a/drivers/video/console/sticon.c b/drivers/video/console/sticon.c
new file mode 100644
index 000000000..6f58e6a9e
--- /dev/null
+++ b/drivers/video/console/sticon.c
@@ -0,0 +1,395 @@
+/*
+ *  linux/drivers/video/console/sticon.c - console driver using HP's STI firmware
+ *
+ *	Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
+ *	Copyright (C) 2002-2020 Helge Deller <deller@gmx.de>
+ *
+ *  Based on linux/drivers/video/vgacon.c and linux/drivers/video/fbcon.c,
+ *  which were
+ *
+ *	Created 28 Sep 1997 by Geert Uytterhoeven
+ *	Rewritten by Martin Mares <mj@ucw.cz>, July 1998
+ *	Copyright (C) 1991, 1992  Linus Torvalds
+ *			    1995  Jay Estabrook
+ *	Copyright (C) 1995 Geert Uytterhoeven
+ *	Copyright (C) 1993 Bjoern Brauel
+ *			   Roman Hodek
+ *	Copyright (C) 1993 Hamish Macdonald
+ *			   Greg Harp
+ *	Copyright (C) 1994 David Carter [carter@compsci.bristol.ac.uk]
+ *
+ *	      with work by William Rucklidge (wjr@cs.cornell.edu)
+ *			   Geert Uytterhoeven
+ *			   Jes Sorensen (jds@kom.auc.dk)
+ *			   Martin Apel
+ *	      with work by Guenther Kelleter
+ *			   Martin Schaller
+ *			   Andreas Schwab
+ *			   Emmanuel Marty (core@ggi-project.org)
+ *			   Jakub Jelinek (jj@ultra.linux.cz)
+ *			   Martin Mares <mj@ucw.cz>
+ *
+ *  This file is subject to the terms and conditions of the GNU General Public
+ *  License.  See the file COPYING in the main directory of this archive for
+ *  more details.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/console.h>
+#include <linux/errno.h>
+#include <linux/vt_kern.h>
+#include <linux/kd.h>
+#include <linux/selection.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/font.h>
+#include <linux/crc32.h>
+#include <linux/fb.h>
+
+#include <asm/io.h>
+
+#include <video/sticore.h>
+
+/* switching to graphics mode */
+#define BLANK 0
+static int vga_is_gfx;
+
+#define STI_DEF_FONT	sticon_sti->font
+
+/* borrowed from fbcon.c */
+#define FNTREFCOUNT(fd)	(fd->refcount)
+#define FNTCRC(fd)	(fd->crc)
+static struct sti_cooked_font *font_data[MAX_NR_CONSOLES];
+
+/* this is the sti_struct used for this console */
+static struct sti_struct *sticon_sti;
+
+static const char *sticon_startup(void)
+{
+    return "STI console";
+}
+
+static void sticon_putcs(struct vc_data *conp, const u16 *s, unsigned int count,
+			 unsigned int ypos, unsigned int xpos)
+{
+    if (vga_is_gfx || console_blanked)
+	    return;
+
+    if (conp->vc_mode != KD_TEXT)
+    	    return;
+
+    while (count--) {
+	sti_putc(sticon_sti, scr_readw(s++), ypos, xpos++,
+		 font_data[conp->vc_num]);
+    }
+}
+
+static void sticon_cursor(struct vc_data *conp, bool enable)
+{
+    unsigned short car1;
+
+    /* no cursor update if screen is blanked */
+    if (vga_is_gfx || console_blanked)
+	return;
+
+    car1 = conp->vc_screenbuf[conp->state.x + conp->state.y * conp->vc_cols];
+    if (!enable) {
+	sti_putc(sticon_sti, car1, conp->state.y, conp->state.x,
+		 font_data[conp->vc_num]);
+	return;
+    }
+
+    switch (CUR_SIZE(conp->vc_cursor_type)) {
+    case CUR_UNDERLINE:
+    case CUR_LOWER_THIRD:
+    case CUR_LOWER_HALF:
+    case CUR_TWO_THIRDS:
+    case CUR_BLOCK:
+	sti_putc(sticon_sti, (car1 & 255) + (0 << 8) + (7 << 11),
+		 conp->state.y, conp->state.x, font_data[conp->vc_num]);
+	break;
+    }
+}
+
+static bool sticon_scroll(struct vc_data *conp, unsigned int t,
+		unsigned int b, enum con_scroll dir, unsigned int count)
+{
+    struct sti_struct *sti = sticon_sti;
+
+    if (vga_is_gfx)
+        return false;
+
+    sticon_cursor(conp, false);
+
+    switch (dir) {
+    case SM_UP:
+	sti_bmove(sti, t + count, 0, t, 0, b - t - count, conp->vc_cols,
+		  font_data[conp->vc_num]);
+	sti_clear(sti, b - count, 0, count, conp->vc_cols,
+		  conp->vc_video_erase_char, font_data[conp->vc_num]);
+	break;
+
+    case SM_DOWN:
+	sti_bmove(sti, t, 0, t + count, 0, b - t - count, conp->vc_cols,
+		  font_data[conp->vc_num]);
+	sti_clear(sti, t, 0, count, conp->vc_cols,
+		  conp->vc_video_erase_char, font_data[conp->vc_num]);
+	break;
+    }
+
+    return false;
+}
+
+static void sticon_set_def_font(int unit)
+{
+	if (font_data[unit] != STI_DEF_FONT) {
+		if (--FNTREFCOUNT(font_data[unit]) == 0) {
+			kfree(font_data[unit]->raw_ptr);
+			kfree(font_data[unit]);
+		}
+		font_data[unit] = STI_DEF_FONT;
+	}
+}
+
+static int sticon_set_font(struct vc_data *vc, const struct console_font *op,
+			   unsigned int vpitch)
+{
+	struct sti_struct *sti = sticon_sti;
+	int vc_cols, vc_rows, vc_old_cols, vc_old_rows;
+	int unit = vc->vc_num;
+	int w = op->width;
+	int h = op->height;
+	int size, i, bpc, pitch;
+	struct sti_rom_font *new_font;
+	struct sti_cooked_font *cooked_font;
+	unsigned char *data = op->data, *p;
+
+	if ((w < 6) || (h < 6) || (w > 32) || (h > 32) || (vpitch != 32)
+	    || (op->charcount != 256 && op->charcount != 512))
+		return -EINVAL;
+	pitch = ALIGN(w, 8) / 8;
+	bpc = pitch * h;
+	size = bpc * op->charcount;
+
+	new_font = kmalloc(sizeof(*new_font) + size, STI_LOWMEM);
+	if (!new_font)
+		return -ENOMEM;
+
+	new_font->first_char = 0;
+	new_font->last_char = op->charcount - 1;
+	new_font->width = w;
+	new_font->height = h;
+	new_font->font_type = STI_FONT_HPROMAN8;
+	new_font->bytes_per_char = bpc;
+	new_font->underline_height = 0;
+	new_font->underline_pos = 0;
+
+	cooked_font = kzalloc_obj(*cooked_font);
+	if (!cooked_font) {
+		kfree(new_font);
+		return -ENOMEM;
+	}
+	cooked_font->raw = new_font;
+	cooked_font->raw_ptr = new_font;
+	cooked_font->width = w;
+	cooked_font->height = h;
+	FNTREFCOUNT(cooked_font) = 0;	/* usage counter */
+
+	p = (unsigned char *) new_font;
+	p += sizeof(*new_font);
+	for (i = 0; i < op->charcount; i++) {
+		memcpy(p, data, bpc);
+		data += pitch*32;
+		p += bpc;
+	}
+	FNTCRC(cooked_font) = crc32(0, new_font, size + sizeof(*new_font));
+	sti_font_convert_bytemode(sti, cooked_font);
+	new_font = cooked_font->raw_ptr;
+
+	/* check if font is already used by other console */
+	for (i = 0; i < MAX_NR_CONSOLES; i++) {
+		if (font_data[i] != STI_DEF_FONT
+		    && (FNTCRC(font_data[i]) == FNTCRC(cooked_font))) {
+			kfree(new_font);
+			kfree(cooked_font);
+			/* current font is the same as the new one */
+			if (i == unit)
+				return 0;
+			cooked_font = font_data[i];
+			new_font = cooked_font->raw_ptr;
+			break;
+		}
+	}
+
+	/* clear screen with old font: we now may have less rows */
+	vc_old_rows = vc->vc_rows;
+	vc_old_cols = vc->vc_cols;
+	sti_clear(sticon_sti, 0, 0, vc_old_rows, vc_old_cols,
+		  vc->vc_video_erase_char, font_data[vc->vc_num]);
+
+	/* delete old font in case it is a user font */
+	sticon_set_def_font(unit);
+
+	FNTREFCOUNT(cooked_font)++;
+	font_data[unit] = cooked_font;
+
+	vc_cols = sti_onscreen_x(sti) / cooked_font->width;
+	vc_rows = sti_onscreen_y(sti) / cooked_font->height;
+	vc_resize(vc, vc_cols, vc_rows);
+
+	/* need to repaint screen if cols & rows are same as old font */
+	if (vc_cols == vc_old_cols && vc_rows == vc_old_rows)
+		update_screen(vc);
+
+	return 0;
+}
+
+static int sticon_font_default(struct vc_data *vc, struct console_font *op,
+			       const char *name)
+{
+	sticon_set_def_font(vc->vc_num);
+
+	return 0;
+}
+
+static int sticon_font_set(struct vc_data *vc, const struct console_font *font,
+			   unsigned int vpitch, unsigned int flags)
+{
+	return sticon_set_font(vc, font, vpitch);
+}
+
+static void sticon_init(struct vc_data *c, bool init)
+{
+    struct sti_struct *sti = sticon_sti;
+    int vc_cols, vc_rows;
+
+    sti_set(sti, 0, 0, sti_onscreen_y(sti), sti_onscreen_x(sti), 0);
+    vc_cols = sti_onscreen_x(sti) / sti->font->width;
+    vc_rows = sti_onscreen_y(sti) / sti->font->height;
+    c->vc_can_do_color = 1;
+
+    if (init) {
+	c->vc_cols = vc_cols;
+	c->vc_rows = vc_rows;
+    } else {
+	vc_resize(c, vc_cols, vc_rows);
+    }
+}
+
+static void sticon_deinit(struct vc_data *c)
+{
+    int i;
+
+    /* free memory used by user font */
+    for (i = 0; i < MAX_NR_CONSOLES; i++)
+	sticon_set_def_font(i);
+}
+
+static void sticon_clear(struct vc_data *conp, unsigned int sy, unsigned int sx,
+			 unsigned int width)
+{
+    sti_clear(sticon_sti, sy, sx, 1, width,
+	      conp->vc_video_erase_char, font_data[conp->vc_num]);
+}
+
+static bool sticon_switch(struct vc_data *conp)
+{
+    return true;	/* needs refreshing */
+}
+
+static bool sticon_blank(struct vc_data *c, enum vesa_blank_mode blank,
+			 bool mode_switch)
+{
+    if (blank == VESA_NO_BLANKING) {
+	if (mode_switch)
+	    vga_is_gfx = 0;
+	return true;
+    }
+    sti_clear(sticon_sti, 0, 0, c->vc_rows, c->vc_cols, BLANK,
+	      font_data[c->vc_num]);
+    if (mode_switch)
+	vga_is_gfx = 1;
+
+    return true;
+}
+
+static u8 sticon_build_attr(struct vc_data *conp, u8 color,
+			    enum vc_intensity intens,
+			    bool blink, bool underline, bool reverse,
+			    bool italic)
+{
+	u8 fg = color & 7;
+	u8 bg = (color & 0x70) >> 4;
+
+	if (reverse)
+		return (fg << 3) | bg;
+	else
+		return (bg << 3) | fg;
+}
+
+static void sticon_invert_region(struct vc_data *conp, u16 *p, int count)
+{
+    int col = 1; /* vga_can_do_color; */
+
+    while (count--) {
+	u16 a = scr_readw(p);
+
+	if (col)
+		a = ((a) & 0x88ff) | (((a) & 0x7000) >> 4) | (((a) & 0x0700) << 4);
+	else
+		a = ((a & 0x0700) == 0x0100) ? 0x7000 : 0x7700;
+
+	scr_writew(a, p++);
+    }
+}
+
+static const struct consw sti_con = {
+	.owner			= THIS_MODULE,
+	.con_startup		= sticon_startup,
+	.con_init		= sticon_init,
+	.con_deinit		= sticon_deinit,
+	.con_clear		= sticon_clear,
+	.con_putcs		= sticon_putcs,
+	.con_cursor		= sticon_cursor,
+	.con_scroll		= sticon_scroll,
+	.con_switch		= sticon_switch,
+	.con_blank		= sticon_blank,
+	.con_font_set		= sticon_font_set,
+	.con_font_default	= sticon_font_default,
+	.con_build_attr		= sticon_build_attr,
+	.con_invert_region	= sticon_invert_region,
+};
+
+
+
+static int __init sticonsole_init(void)
+{
+    int err, i;
+
+    /* already initialized ? */
+    if (sticon_sti)
+	 return 0;
+
+    sticon_sti = sti_get_rom(0);
+    if (!sticon_sti)
+	return -ENODEV;
+
+    for (i = 0; i < MAX_NR_CONSOLES; i++)
+	font_data[i] = STI_DEF_FONT;
+
+    pr_info("sticon: Initializing STI text console on %s at [%s]\n",
+	sticon_sti->sti_data->inq_outptr.dev_name,
+	sticon_sti->pa_path);
+    console_lock();
+    err = do_take_over_console(&sti_con, 0, MAX_NR_CONSOLES - 1,
+		PAGE0->mem_cons.cl_class != CL_DUPLEX);
+    console_unlock();
+
+    return err;
+}
+
+module_init(sticonsole_init);
+MODULE_DESCRIPTION("HP STI console driver");
+MODULE_LICENSE("GPL");