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, 534 insertions, 0 deletions

diff --git a/tools/spi/spidev_test.c b/tools/spi/spidev_test.c
new file mode 100644
index 000000000..f2135d619
--- /dev/null
+++ b/tools/spi/spidev_test.c
@@ -0,0 +1,534 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SPI testing utility (using spidev driver)
+ *
+ * Copyright (c) 2007  MontaVista Software, Inc.
+ * Copyright (c) 2007  Anton Vorontsov <avorontsov@ru.mvista.com>
+ *
+ * Cross-compile with cross-gcc -I/path/to/cross-kernel/include
+ */
+
+#include <stdint.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <getopt.h>
+#include <fcntl.h>
+#include <time.h>
+#include <sys/ioctl.h>
+#include <linux/ioctl.h>
+#include <sys/stat.h>
+#include <linux/types.h>
+#include <linux/spi/spidev.h>
+
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
+
+static void pabort(const char *s)
+{
+	if (errno != 0)
+		perror(s);
+	else
+		printf("%s\n", s);
+
+	abort();
+}
+
+static const char *device = "/dev/spidev1.1";
+static uint32_t mode;
+static uint8_t bits = 8;
+static char *input_file;
+static char *output_file;
+static uint32_t speed = 500000;
+static uint16_t delay;
+static uint16_t word_delay;
+static int verbose;
+static int transfer_size;
+static int iterations;
+static int interval = 5; /* interval in seconds for showing transfer rate */
+
+static uint8_t default_tx[] = {
+	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+	0x40, 0x00, 0x00, 0x00, 0x00, 0x95,
+	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+	0xF0, 0x0D,
+};
+
+static uint8_t default_rx[ARRAY_SIZE(default_tx)] = {0, };
+static char *input_tx;
+
+static void hex_dump(const void *src, size_t length, size_t line_size,
+		     char *prefix)
+{
+	int i = 0;
+	const unsigned char *address = src;
+	const unsigned char *line = address;
+	unsigned char c;
+
+	printf("%s | ", prefix);
+	while (length-- > 0) {
+		printf("%02X ", *address++);
+		if (!(++i % line_size) || (length == 0 && i % line_size)) {
+			if (length == 0) {
+				while (i++ % line_size)
+					printf("__ ");
+			}
+			printf(" |");
+			while (line < address) {
+				c = *line++;
+				printf("%c", (c < 32 || c > 126) ? '.' : c);
+			}
+			printf("|\n");
+			if (length > 0)
+				printf("%s | ", prefix);
+		}
+	}
+}
+
+/*
+ *  Unescape - process hexadecimal escape character
+ *      converts shell input "\x23" -> 0x23
+ */
+static int unescape(char *_dst, char *_src, size_t len)
+{
+	int ret = 0;
+	int match;
+	char *src = _src;
+	char *dst = _dst;
+	unsigned int ch;
+
+	while (*src) {
+		if (*src == '\\' && *(src+1) == 'x') {
+			match = sscanf(src + 2, "%2x", &ch);
+			if (!match)
+				pabort("malformed input string");
+
+			src += 4;
+			*dst++ = (unsigned char)ch;
+		} else {
+			*dst++ = *src++;
+		}
+		ret++;
+	}
+	return ret;
+}
+
+static void transfer(int fd, uint8_t const *tx, uint8_t const *rx, size_t len)
+{
+	int ret;
+	int out_fd;
+	struct spi_ioc_transfer tr = {
+		.tx_buf = (unsigned long)tx,
+		.rx_buf = (unsigned long)rx,
+		.len = len,
+		.delay_usecs = delay,
+		.word_delay_usecs = word_delay,
+		.speed_hz = speed,
+		.bits_per_word = bits,
+	};
+
+	if (mode & SPI_TX_OCTAL)
+		tr.tx_nbits = 8;
+	else if (mode & SPI_TX_QUAD)
+		tr.tx_nbits = 4;
+	else if (mode & SPI_TX_DUAL)
+		tr.tx_nbits = 2;
+	if (mode & SPI_RX_OCTAL)
+		tr.rx_nbits = 8;
+	else if (mode & SPI_RX_QUAD)
+		tr.rx_nbits = 4;
+	else if (mode & SPI_RX_DUAL)
+		tr.rx_nbits = 2;
+	if (!(mode & SPI_LOOP)) {
+		if (mode & (SPI_TX_OCTAL | SPI_TX_QUAD | SPI_TX_DUAL))
+			tr.rx_buf = 0;
+		else if (mode & (SPI_RX_OCTAL | SPI_RX_QUAD | SPI_RX_DUAL))
+			tr.tx_buf = 0;
+	}
+
+	ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
+	if (ret < 1)
+		pabort("can't send spi message");
+
+	if (verbose)
+		hex_dump(tx, len, 32, "TX");
+
+	if (output_file) {
+		out_fd = open(output_file, O_WRONLY | O_CREAT | O_TRUNC, 0666);
+		if (out_fd < 0)
+			pabort("could not open output file");
+
+		ret = write(out_fd, rx, len);
+		if (ret != len)
+			pabort("not all bytes written to output file");
+
+		close(out_fd);
+	}
+
+	if (verbose)
+		hex_dump(rx, len, 32, "RX");
+}
+
+static void print_usage(const char *prog)
+{
+	printf("Usage: %s [-2348CDFHILMNORSZbdilopsvw]\n", prog);
+	puts("general device settings:\n"
+		 "  -D --device         device to use (default /dev/spidev1.1)\n"
+		 "  -s --speed          max speed (Hz)\n"
+		 "  -d --delay          delay (usec)\n"
+		 "  -w --word-delay     word delay (usec)\n"
+		 "  -l --loop           loopback\n"
+		 "spi mode:\n"
+		 "  -H --cpha           clock phase\n"
+		 "  -O --cpol           clock polarity\n"
+		 "  -F --rx-cpha-flip   flip CPHA on Rx only xfer\n"
+		 "number of wires for transmission:\n"
+		 "  -2 --dual           dual transfer\n"
+		 "  -4 --quad           quad transfer\n"
+		 "  -8 --octal          octal transfer\n"
+		 "  -3 --3wire          SI/SO signals shared\n"
+		 "  -Z --3wire-hiz      high impedance turnaround\n"
+		 "data:\n"
+		 "  -i --input          input data from a file (e.g. \"test.bin\")\n"
+		 "  -o --output         output data to a file (e.g. \"results.bin\")\n"
+		 "  -p                  Send data (e.g. \"1234\\xde\\xad\")\n"
+		 "  -S --size           transfer size\n"
+		 "  -I --iter           iterations\n"
+		 "additional parameters:\n"
+		 "  -b --bpw            bits per word\n"
+		 "  -L --lsb            least significant bit first\n"
+		 "  -C --cs-high        chip select active high\n"
+		 "  -N --no-cs          no chip select\n"
+		 "  -R --ready          slave pulls low to pause\n"
+		 "  -M --mosi-idle-low  leave mosi line low when idle\n"
+		 "misc:\n"
+		 "  -v --verbose        Verbose (show tx buffer)\n");
+	exit(1);
+}
+
+static void parse_opts(int argc, char *argv[])
+{
+	while (1) {
+		static const struct option lopts[] = {
+			{ "device",        1, 0, 'D' },
+			{ "speed",         1, 0, 's' },
+			{ "delay",         1, 0, 'd' },
+			{ "word-delay",    1, 0, 'w' },
+			{ "loop",          0, 0, 'l' },
+			{ "cpha",          0, 0, 'H' },
+			{ "cpol",          0, 0, 'O' },
+			{ "rx-cpha-flip",  0, 0, 'F' },
+			{ "dual",          0, 0, '2' },
+			{ "quad",          0, 0, '4' },
+			{ "octal",         0, 0, '8' },
+			{ "3wire",         0, 0, '3' },
+			{ "3wire-hiz",     0, 0, 'Z' },
+			{ "input",         1, 0, 'i' },
+			{ "output",        1, 0, 'o' },
+			{ "size",          1, 0, 'S' },
+			{ "iter",          1, 0, 'I' },
+			{ "bpw",           1, 0, 'b' },
+			{ "lsb",           0, 0, 'L' },
+			{ "cs-high",       0, 0, 'C' },
+			{ "no-cs",         0, 0, 'N' },
+			{ "ready",         0, 0, 'R' },
+			{ "mosi-idle-low", 0, 0, 'M' },
+			{ "verbose",       0, 0, 'v' },
+			{ NULL, 0, 0, 0 },
+		};
+		int c;
+
+		c = getopt_long(argc, argv, "D:s:d:w:b:i:o:lHOLC3ZFMNR248p:vS:I:",
+				lopts, NULL);
+
+		if (c == -1)
+			break;
+
+		switch (c) {
+		case 'D':
+			device = optarg;
+			break;
+		case 's':
+			speed = atoi(optarg);
+			break;
+		case 'd':
+			delay = atoi(optarg);
+			break;
+		case 'w':
+			word_delay = atoi(optarg);
+			break;
+		case 'b':
+			bits = atoi(optarg);
+			break;
+		case 'i':
+			input_file = optarg;
+			break;
+		case 'o':
+			output_file = optarg;
+			break;
+		case 'l':
+			mode |= SPI_LOOP;
+			break;
+		case 'H':
+			mode |= SPI_CPHA;
+			break;
+		case 'O':
+			mode |= SPI_CPOL;
+			break;
+		case 'L':
+			mode |= SPI_LSB_FIRST;
+			break;
+		case 'C':
+			mode |= SPI_CS_HIGH;
+			break;
+		case '3':
+			mode |= SPI_3WIRE;
+			break;
+		case 'Z':
+			mode |= SPI_3WIRE_HIZ;
+			break;
+		case 'F':
+			mode |= SPI_RX_CPHA_FLIP;
+			break;
+		case 'M':
+			mode |= SPI_MOSI_IDLE_LOW;
+			break;
+		case 'N':
+			mode |= SPI_NO_CS;
+			break;
+		case 'v':
+			verbose = 1;
+			break;
+		case 'R':
+			mode |= SPI_READY;
+			break;
+		case 'p':
+			input_tx = optarg;
+			break;
+		case '2':
+			mode |= SPI_TX_DUAL;
+			break;
+		case '4':
+			mode |= SPI_TX_QUAD;
+			break;
+		case '8':
+			mode |= SPI_TX_OCTAL;
+			break;
+		case 'S':
+			transfer_size = atoi(optarg);
+			break;
+		case 'I':
+			iterations = atoi(optarg);
+			break;
+		default:
+			print_usage(argv[0]);
+		}
+	}
+	if (mode & SPI_LOOP) {
+		if (mode & SPI_TX_DUAL)
+			mode |= SPI_RX_DUAL;
+		if (mode & SPI_TX_QUAD)
+			mode |= SPI_RX_QUAD;
+		if (mode & SPI_TX_OCTAL)
+			mode |= SPI_RX_OCTAL;
+	}
+}
+
+static void transfer_escaped_string(int fd, char *str)
+{
+	size_t size = strlen(str);
+	uint8_t *tx;
+	uint8_t *rx;
+
+	tx = malloc(size);
+	if (!tx)
+		pabort("can't allocate tx buffer");
+
+	rx = malloc(size);
+	if (!rx)
+		pabort("can't allocate rx buffer");
+
+	size = unescape((char *)tx, str, size);
+	transfer(fd, tx, rx, size);
+	free(rx);
+	free(tx);
+}
+
+static void transfer_file(int fd, char *filename)
+{
+	ssize_t bytes;
+	struct stat sb;
+	int tx_fd;
+	uint8_t *tx;
+	uint8_t *rx;
+
+	if (stat(filename, &sb) == -1)
+		pabort("can't stat input file");
+
+	tx_fd = open(filename, O_RDONLY);
+	if (tx_fd < 0)
+		pabort("can't open input file");
+
+	tx = malloc(sb.st_size);
+	if (!tx)
+		pabort("can't allocate tx buffer");
+
+	rx = malloc(sb.st_size);
+	if (!rx)
+		pabort("can't allocate rx buffer");
+
+	bytes = read(tx_fd, tx, sb.st_size);
+	if (bytes != sb.st_size)
+		pabort("failed to read input file");
+
+	transfer(fd, tx, rx, sb.st_size);
+	free(rx);
+	free(tx);
+	close(tx_fd);
+}
+
+static uint64_t _read_count;
+static uint64_t _write_count;
+
+static void show_transfer_rate(void)
+{
+	static uint64_t prev_read_count, prev_write_count;
+	double rx_rate, tx_rate;
+
+	rx_rate = ((_read_count - prev_read_count) * 8) / (interval*1000.0);
+	tx_rate = ((_write_count - prev_write_count) * 8) / (interval*1000.0);
+
+	printf("rate: tx %.1fkbps, rx %.1fkbps\n", rx_rate, tx_rate);
+
+	prev_read_count = _read_count;
+	prev_write_count = _write_count;
+}
+
+static void transfer_buf(int fd, int len)
+{
+	uint8_t *tx;
+	uint8_t *rx;
+	int i;
+
+	tx = malloc(len);
+	if (!tx)
+		pabort("can't allocate tx buffer");
+	for (i = 0; i < len; i++)
+		tx[i] = random();
+
+	rx = malloc(len);
+	if (!rx)
+		pabort("can't allocate rx buffer");
+
+	transfer(fd, tx, rx, len);
+
+	_write_count += len;
+	_read_count += len;
+
+	if (mode & SPI_LOOP) {
+		if (memcmp(tx, rx, len)) {
+			fprintf(stderr, "transfer error !\n");
+			hex_dump(tx, len, 32, "TX");
+			hex_dump(rx, len, 32, "RX");
+			exit(1);
+		}
+	}
+
+	free(rx);
+	free(tx);
+}
+
+int main(int argc, char *argv[])
+{
+	int ret = 0;
+	int fd;
+	uint32_t request;
+
+	parse_opts(argc, argv);
+
+	if (input_tx && input_file)
+		pabort("only one of -p and --input may be selected");
+
+	fd = open(device, O_RDWR);
+	if (fd < 0)
+		pabort("can't open device");
+
+	/*
+	 * spi mode
+	 */
+	/* WR is make a request to assign 'mode' */
+	request = mode;
+	ret = ioctl(fd, SPI_IOC_WR_MODE32, &mode);
+	if (ret == -1)
+		pabort("can't set spi mode");
+
+	/* RD is read what mode the device actually is in */
+	ret = ioctl(fd, SPI_IOC_RD_MODE32, &mode);
+	if (ret == -1)
+		pabort("can't get spi mode");
+	/* Drivers can reject some mode bits without returning an error.
+	 * Read the current value to identify what mode it is in, and if it
+	 * differs from the requested mode, warn the user.
+	 */
+	if (request != mode)
+		printf("WARNING device does not support requested mode 0x%x\n",
+			request);
+
+	/*
+	 * bits per word
+	 */
+	ret = ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
+	if (ret == -1)
+		pabort("can't set bits per word");
+
+	ret = ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits);
+	if (ret == -1)
+		pabort("can't get bits per word");
+
+	/*
+	 * max speed hz
+	 */
+	ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
+	if (ret == -1)
+		pabort("can't set max speed hz");
+
+	ret = ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
+	if (ret == -1)
+		pabort("can't get max speed hz");
+
+	printf("spi mode: 0x%x\n", mode);
+	printf("bits per word: %u\n", bits);
+	printf("max speed: %u Hz (%u kHz)\n", speed, speed/1000);
+
+	if (input_tx)
+		transfer_escaped_string(fd, input_tx);
+	else if (input_file)
+		transfer_file(fd, input_file);
+	else if (transfer_size) {
+		struct timespec last_stat;
+
+		clock_gettime(CLOCK_MONOTONIC, &last_stat);
+
+		while (iterations-- > 0) {
+			struct timespec current;
+
+			transfer_buf(fd, transfer_size);
+
+			clock_gettime(CLOCK_MONOTONIC, &current);
+			if (current.tv_sec - last_stat.tv_sec > interval) {
+				show_transfer_rate();
+				last_stat = current;
+			}
+		}
+		printf("total: tx %.1fKB, rx %.1fKB\n",
+		       _write_count/1024.0, _read_count/1024.0);
+	} else
+		transfer(fd, default_tx, default_rx, sizeof(default_tx));
+
+	close(fd);
+
+	return ret;
+}