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, 216 insertions, 0 deletions

diff --git a/drivers/accessibility/speakup/keyhelp.c b/drivers/accessibility/speakup/keyhelp.c
new file mode 100644
index 000000000..0940f430a
--- /dev/null
+++ b/drivers/accessibility/speakup/keyhelp.c
@@ -0,0 +1,216 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* speakup_keyhelp.c
+ * help module for speakup
+ *
+ *written by David Borowski.
+ *
+ *  Copyright (C) 2003  David Borowski.
+ */
+
+#include <linux/keyboard.h>
+#include <linux/ctype.h>
+#include "spk_priv.h"
+#include "speakup.h"
+
+#define MAXFUNCS 130
+#define MAXKEYS 256
+static const int num_key_names = MSG_KEYNAMES_END - MSG_KEYNAMES_START + 1;
+static u16 key_offsets[MAXFUNCS], key_data[MAXKEYS];
+static u16 masks[] = { 32, 16, 8, 4, 2, 1 };
+
+static short letter_offsets[26] = {
+	-1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1 };
+
+static u_char funcvals[] = {
+	ATTRIB_BLEEP_DEC, ATTRIB_BLEEP_INC, BLEEPS_DEC, BLEEPS_INC,
+	SAY_FIRST_CHAR, SAY_LAST_CHAR, SAY_CHAR, SAY_CHAR_NUM,
+	SAY_NEXT_CHAR, SAY_PHONETIC_CHAR, SAY_PREV_CHAR, SPEAKUP_PARKED,
+	SPEAKUP_CUT, EDIT_DELIM, EDIT_EXNUM, EDIT_MOST,
+	EDIT_REPEAT, EDIT_SOME, SPEAKUP_GOTO, BOTTOM_EDGE,
+	LEFT_EDGE, RIGHT_EDGE, TOP_EDGE, SPEAKUP_HELP,
+	SAY_LINE, SAY_NEXT_LINE, SAY_PREV_LINE, SAY_LINE_INDENT,
+	SPEAKUP_PASTE, PITCH_DEC, PITCH_INC, PUNCT_DEC,
+	PUNCT_INC, PUNC_LEVEL_DEC, PUNC_LEVEL_INC, SPEAKUP_QUIET,
+	RATE_DEC, RATE_INC, READING_PUNC_DEC, READING_PUNC_INC,
+	SAY_ATTRIBUTES, SAY_FROM_LEFT, SAY_FROM_TOP, SAY_POSITION,
+	SAY_SCREEN, SAY_TO_BOTTOM, SAY_TO_RIGHT, SPK_KEY,
+	SPK_LOCK, SPEAKUP_OFF, SPEECH_KILL, SPELL_DELAY_DEC,
+	SPELL_DELAY_INC, SPELL_WORD, SPELL_PHONETIC, TONE_DEC,
+	TONE_INC, VOICE_DEC, VOICE_INC, VOL_DEC,
+	VOL_INC, CLEAR_WIN, SAY_WIN, SET_WIN,
+	ENABLE_WIN, SAY_WORD, SAY_NEXT_WORD, SAY_PREV_WORD, 0
+};
+
+static u_char *state_tbl;
+static int cur_item, nstates;
+
+static void build_key_data(void)
+{
+	u_char *kp, counters[MAXFUNCS], ch, ch1;
+	u16 *p_key, key;
+	int i, offset = 1;
+
+	nstates = (int)(state_tbl[-1]);
+	memset(counters, 0, sizeof(counters));
+	memset(key_offsets, 0, sizeof(key_offsets));
+	kp = state_tbl + nstates + 1;
+	while (*kp++) {
+		/* count occurrences of each function */
+		for (i = 0; i < nstates; i++, kp++) {
+			if (!*kp)
+				continue;
+			if ((state_tbl[i] & 16) != 0 && *kp == SPK_KEY)
+				continue;
+			counters[*kp]++;
+		}
+	}
+	for (i = 0; i < MAXFUNCS; i++) {
+		if (counters[i] == 0)
+			continue;
+		key_offsets[i] = offset;
+		offset += (counters[i] + 1);
+		if (offset >= MAXKEYS)
+			break;
+	}
+/* leave counters set so high keycodes come first.
+ * this is done so num pad and other extended keys maps are spoken before
+ * the alpha with speakup type mapping.
+ */
+	kp = state_tbl + nstates + 1;
+	while ((ch = *kp++)) {
+		for (i = 0; i < nstates; i++) {
+			ch1 = *kp++;
+			if (!ch1)
+				continue;
+			if ((state_tbl[i] & 16) != 0 && ch1 == SPK_KEY)
+				continue;
+			key = (state_tbl[i] << 8) + ch;
+			counters[ch1]--;
+			offset = key_offsets[ch1];
+			if (!offset)
+				continue;
+			p_key = key_data + offset + counters[ch1];
+			*p_key = key;
+		}
+	}
+}
+
+static void say_key(int key)
+{
+	int i, state = key >> 8;
+
+	key &= 0xff;
+	for (i = 0; i < 6; i++) {
+		if (state & masks[i])
+			synth_printf(" %s", spk_msg_get(MSG_STATES_START + i));
+	}
+	if ((key > 0) && (key <= num_key_names))
+		synth_printf(" %s\n",
+			     spk_msg_get(MSG_KEYNAMES_START + (key - 1)));
+}
+
+static void help_init(void)
+{
+	char start = SPACE;
+	int i;
+	int num_funcs = MSG_FUNCNAMES_END - MSG_FUNCNAMES_START + 1;
+
+	state_tbl = spk_our_keys[0] + SHIFT_TBL_SIZE + 2;
+	for (i = 0; i < num_funcs; i++) {
+		char *cur_funcname = spk_msg_get(MSG_FUNCNAMES_START + i);
+		char first_letter;
+
+		first_letter = tolower(*cur_funcname);
+
+		/* Accept only 'a'..'z' to index letter_offsets[] safely */
+		if (first_letter < 'a' || first_letter > 'z')
+			continue;
+
+		if (start == first_letter)
+			continue;
+		start = first_letter;
+		letter_offsets[(start & 31) - 1] = i;
+	}
+}
+
+int spk_handle_help(struct vc_data *vc, u_char type, u_char ch, u16 key)
+{
+	int i, n;
+	char *name;
+	u_char func, *kp;
+	u16 *p_keys, val;
+
+	if (letter_offsets[0] == -1)
+		help_init();
+	if (type == KT_LATIN) {
+		if (ch == SPACE) {
+			spk_special_handler = NULL;
+			synth_printf("%s\n", spk_msg_get(MSG_LEAVING_HELP));
+			return 1;
+		}
+		ch = tolower(ch);
+		if (ch < 'a' || ch > 'z')
+			return -1;
+		if (letter_offsets[ch - 'a'] == -1) {
+			synth_printf(spk_msg_get(MSG_NO_COMMAND), ch);
+			synth_printf("\n");
+			return 1;
+		}
+		cur_item = letter_offsets[ch - 'a'];
+	} else if (type == KT_CUR) {
+		if (ch == 0 &&
+		    (MSG_FUNCNAMES_START + cur_item + 1) <= MSG_FUNCNAMES_END)
+			cur_item++;
+		else if (ch == 3 && cur_item > 0)
+			cur_item--;
+		else
+			return -1;
+	} else if (type == KT_SPKUP && ch == SPEAKUP_HELP &&
+		   !spk_special_handler) {
+		spk_special_handler = spk_handle_help;
+		synth_printf("%s\n", spk_msg_get(MSG_HELP_INFO));
+		build_key_data(); /* rebuild each time in case new mapping */
+		return 1;
+	} else {
+		name = NULL;
+		if ((type != KT_SPKUP) && (key > 0) && (key <= num_key_names)) {
+			synth_printf("%s\n",
+				     spk_msg_get(MSG_KEYNAMES_START + key - 1));
+			return 1;
+		}
+		for (i = 0; funcvals[i] != 0 && !name; i++) {
+			if (ch == funcvals[i])
+				name = spk_msg_get(MSG_FUNCNAMES_START + i);
+		}
+		if (!name)
+			return -1;
+		kp = spk_our_keys[key] + 1;
+		for (i = 0; i < nstates; i++) {
+			if (ch == kp[i])
+				break;
+		}
+		key += (state_tbl[i] << 8);
+		say_key(key);
+		synth_printf(spk_msg_get(MSG_KEYDESC), name);
+		synth_printf("\n");
+		return 1;
+	}
+	name = spk_msg_get(MSG_FUNCNAMES_START + cur_item);
+	func = funcvals[cur_item];
+	synth_printf("%s", name);
+	if (key_offsets[func] == 0) {
+		synth_printf(" %s\n", spk_msg_get(MSG_IS_UNASSIGNED));
+		return 1;
+	}
+	p_keys = key_data + key_offsets[func];
+	for (n = 0; p_keys[n]; n++) {
+		val = p_keys[n];
+		if (n > 0)
+			synth_printf("%s ", spk_msg_get(MSG_DISJUNCTION));
+		say_key(val);
+	}
+	return 1;
+}