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, 160 insertions, 0 deletions

diff --git a/drivers/accessibility/speakup/genmap.c b/drivers/accessibility/speakup/genmap.c
new file mode 100644
index 000000000..a9e308bdd
--- /dev/null
+++ b/drivers/accessibility/speakup/genmap.c
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* genmap.c
+ * originally written by: Kirk Reiser.
+ *
+ ** Copyright (C) 2002  Kirk Reiser.
+ *  Copyright (C) 2003  David Borowski.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <libgen.h>
+#include <string.h>
+#include <ctype.h>
+#include "utils.h"
+
+struct st_key_init {
+	char *name;
+	int value, shift;
+};
+
+static unsigned char key_data[MAXKEYVAL][16], *kp;
+
+#include "mapdata.h"
+
+static const char delims[] = "\t\n ";
+static char *cp;
+static int map_ver = 119; /* an arbitrary number so speakup can check */
+static int shift_table[17];
+static int max_states = 1, flags;
+/* flags reserved for later, maybe for individual console maps */
+
+static int get_shift_value(int state)
+{
+	int i;
+
+	for (i = 0; shift_table[i] != state; i++) {
+		if (shift_table[i] == -1) {
+			if (i >= 16)
+				oops("too many shift states", NULL);
+			shift_table[i] = state;
+			max_states = i+1;
+		break;
+	}
+	}
+	return i;
+}
+
+int
+main(int argc, char *argv[])
+{
+	int value, shift_state, i, spk_val = 0, lock_val = 0;
+	int max_key_used = 0, num_keys_used = 0;
+	struct st_key *this;
+	struct st_key_init *p_init;
+	char buffer[256];
+
+	bzero(key_table, sizeof(key_table));
+	bzero(key_data, sizeof(key_data));
+
+	shift_table[0] = 0;
+	for (i = 1; i <= 16; i++)
+		shift_table[i] = -1;
+
+	if (argc < 2) {
+		fputs("usage: genmap filename\n", stderr);
+		exit(1);
+	}
+
+	for (p_init = init_key_data; p_init->name[0] != '.'; p_init++)
+		add_key(p_init->name, p_init->value, p_init->shift);
+
+	open_input(NULL, argv[1]);
+	while (fgets(buffer, sizeof(buffer), infile)) {
+		value = shift_state = 0;
+
+		cp = strtok(buffer, delims);
+		if (*cp == '#')
+			continue;
+
+		while (cp) {
+			if (*cp == '=')
+				break;
+			this = find_key(cp);
+			if (this == NULL)
+				oops("unknown key/modifier", cp);
+			if (this->shift == is_shift) {
+				if (value)
+					oops("modifiers must come first", cp);
+				shift_state += this->value;
+			} else if (this->shift == is_input)
+				value = this->value;
+			else
+				oops("bad modifier or key", cp);
+			cp = strtok(0, delims);
+		}
+		if (!cp)
+			oops("no = found", NULL);
+
+		cp = strtok(0, delims);
+		if (!cp)
+			oops("no speakup function after =", NULL);
+
+		this = find_key(cp);
+		if (this == NULL || this->shift != is_spk)
+			oops("invalid speakup function", cp);
+
+		i = get_shift_value(shift_state);
+		if (key_data[value][i]) {
+			while (--cp > buffer)
+				if (!*cp)
+					*cp = ' ';
+			oops("two functions on same key combination", cp);
+		}
+		key_data[value][i] = (char)this->value;
+		if (value > max_key_used)
+			max_key_used = value;
+	}
+	fclose(infile);
+
+	this = find_key("spk_key");
+	if (this)
+		spk_val = this->value;
+
+	this = find_key("spk_lock");
+	if (this)
+		lock_val = this->value;
+
+	for (lc = 1; lc <= max_key_used; lc++) {
+		kp = key_data[lc];
+		if (!memcmp(key_data[0], kp, 16))
+			continue;
+		num_keys_used++;
+		for (i = 0; i < max_states; i++) {
+			if (kp[i] != spk_val && kp[i] != lock_val)
+				continue;
+			shift_state = shift_table[i];
+			if (shift_state&16)
+				continue;
+			shift_state = get_shift_value(shift_state+16);
+			kp[shift_state] = kp[i];
+			/* fill in so we can process the key up, as spk bit will be set */
+		}
+	}
+
+	printf("\t%d, %d, %d,\n\t", map_ver, num_keys_used, max_states);
+	for (i = 0; i < max_states; i++)
+		printf("%d, ", shift_table[i]);
+	printf("%d,", flags);
+	for (lc = 1; lc <= max_key_used; lc++) {
+		kp = key_data[lc];
+		if (!memcmp(key_data[0], kp, 16))
+			continue;
+		printf("\n\t%d,", lc);
+		for (i = 0; i < max_states; i++)
+			printf(" %u,", (unsigned int)kp[i]);
+	}
+	printf("\n\t0, %d\n", map_ver);
+
+	exit(0);
+}