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, 418 insertions, 0 deletions

diff --git a/drivers/mtd/tests/speedtest.c b/drivers/mtd/tests/speedtest.c
new file mode 100644
index 000000000..075bce32c
--- /dev/null
+++ b/drivers/mtd/tests/speedtest.c
@@ -0,0 +1,418 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2007 Nokia Corporation
+ *
+ * Test read and write speed of a MTD device.
+ *
+ * Author: Adrian Hunter <adrian.hunter@nokia.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/ktime.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/err.h>
+#include <linux/mtd/mtd.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/random.h>
+
+#include "mtd_test.h"
+
+static int dev = -EINVAL;
+module_param(dev, int, S_IRUGO);
+MODULE_PARM_DESC(dev, "MTD device number to use");
+
+static int count;
+module_param(count, int, S_IRUGO);
+MODULE_PARM_DESC(count, "Maximum number of eraseblocks to use "
+			"(0 means use all)");
+
+static struct mtd_info *mtd;
+static unsigned char *iobuf;
+static unsigned char *bbt;
+
+static int pgsize;
+static int ebcnt;
+static int pgcnt;
+static int goodebcnt;
+static ktime_t start, finish;
+
+static int multiblock_erase(int ebnum, int blocks)
+{
+	int err;
+	struct erase_info ei;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	memset(&ei, 0, sizeof(struct erase_info));
+	ei.addr = addr;
+	ei.len  = mtd->erasesize * blocks;
+
+	err = mtd_erase(mtd, &ei);
+	if (err) {
+		pr_err("error %d while erasing EB %d, blocks %d\n",
+		       err, ebnum, blocks);
+		return err;
+	}
+
+	return 0;
+}
+
+static int write_eraseblock(int ebnum)
+{
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	return mtdtest_write(mtd, addr, mtd->erasesize, iobuf);
+}
+
+static int write_eraseblock_by_page(int ebnum)
+{
+	int i, err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+	void *buf = iobuf;
+
+	for (i = 0; i < pgcnt; i++) {
+		err = mtdtest_write(mtd, addr, pgsize, buf);
+		if (err)
+			break;
+		addr += pgsize;
+		buf += pgsize;
+	}
+
+	return err;
+}
+
+static int write_eraseblock_by_2pages(int ebnum)
+{
+	size_t sz = pgsize * 2;
+	int i, n = pgcnt / 2, err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+	void *buf = iobuf;
+
+	for (i = 0; i < n; i++) {
+		err = mtdtest_write(mtd, addr, sz, buf);
+		if (err)
+			return err;
+		addr += sz;
+		buf += sz;
+	}
+	if (pgcnt % 2)
+		err = mtdtest_write(mtd, addr, pgsize, buf);
+
+	return err;
+}
+
+static int read_eraseblock(int ebnum)
+{
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	return mtdtest_read(mtd, addr, mtd->erasesize, iobuf);
+}
+
+static int read_eraseblock_by_page(int ebnum)
+{
+	int i, err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+	void *buf = iobuf;
+
+	for (i = 0; i < pgcnt; i++) {
+		err = mtdtest_read(mtd, addr, pgsize, buf);
+		if (err)
+			break;
+		addr += pgsize;
+		buf += pgsize;
+	}
+
+	return err;
+}
+
+static int read_eraseblock_by_2pages(int ebnum)
+{
+	size_t sz = pgsize * 2;
+	int i, n = pgcnt / 2, err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+	void *buf = iobuf;
+
+	for (i = 0; i < n; i++) {
+		err = mtdtest_read(mtd, addr, sz, buf);
+		if (err)
+			return err;
+		addr += sz;
+		buf += sz;
+	}
+	if (pgcnt % 2)
+		err = mtdtest_read(mtd, addr, pgsize, buf);
+
+	return err;
+}
+
+static inline void start_timing(void)
+{
+	start = ktime_get();
+}
+
+static inline void stop_timing(void)
+{
+	finish = ktime_get();
+}
+
+static long calc_speed(void)
+{
+	uint64_t k, us;
+
+	us = ktime_us_delta(finish, start);
+	if (us == 0)
+		return 0;
+	k = (uint64_t)goodebcnt * (mtd->erasesize / 1024) * 1000000;
+	do_div(k, us);
+	return k;
+}
+
+static int __init mtd_speedtest_init(void)
+{
+	int err, i, blocks, j, k;
+	long speed;
+	uint64_t tmp;
+
+	printk(KERN_INFO "\n");
+	printk(KERN_INFO "=================================================\n");
+
+	if (dev < 0) {
+		pr_info("Please specify a valid mtd-device via module parameter\n");
+		pr_crit("CAREFUL: This test wipes all data on the specified MTD device!\n");
+		return -EINVAL;
+	}
+
+	if (count)
+		pr_info("MTD device: %d    count: %d\n", dev, count);
+	else
+		pr_info("MTD device: %d\n", dev);
+
+	mtd = get_mtd_device(NULL, dev);
+	if (IS_ERR(mtd)) {
+		err = PTR_ERR(mtd);
+		pr_err("error: cannot get MTD device\n");
+		return err;
+	}
+
+	if (mtd->writesize == 1) {
+		pr_info("not NAND flash, assume page size is 512 "
+		       "bytes.\n");
+		pgsize = 512;
+	} else
+		pgsize = mtd->writesize;
+
+	tmp = mtd->size;
+	do_div(tmp, mtd->erasesize);
+	ebcnt = tmp;
+	pgcnt = mtd->erasesize / pgsize;
+
+	pr_info("MTD device size %llu, eraseblock size %u, "
+	       "page size %u, count of eraseblocks %u, pages per "
+	       "eraseblock %u, OOB size %u\n",
+	       (unsigned long long)mtd->size, mtd->erasesize,
+	       pgsize, ebcnt, pgcnt, mtd->oobsize);
+
+	if (count > 0 && count < ebcnt)
+		ebcnt = count;
+
+	err = -ENOMEM;
+	iobuf = kmalloc(mtd->erasesize, GFP_KERNEL);
+	if (!iobuf)
+		goto out;
+
+	get_random_bytes(iobuf, mtd->erasesize);
+
+	bbt = kzalloc(ebcnt, GFP_KERNEL);
+	if (!bbt)
+		goto out;
+	err = mtdtest_scan_for_bad_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+	for (i = 0; i < ebcnt; i++) {
+		if (!bbt[i])
+			goodebcnt++;
+	}
+
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+
+	/* Write all eraseblocks, 1 eraseblock at a time */
+	pr_info("testing eraseblock write speed\n");
+	start_timing();
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = write_eraseblock(i);
+		if (err)
+			goto out;
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	stop_timing();
+	speed = calc_speed();
+	pr_info("eraseblock write speed is %ld KiB/s\n", speed);
+
+	/* Read all eraseblocks, 1 eraseblock at a time */
+	pr_info("testing eraseblock read speed\n");
+	start_timing();
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = read_eraseblock(i);
+		if (err)
+			goto out;
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	stop_timing();
+	speed = calc_speed();
+	pr_info("eraseblock read speed is %ld KiB/s\n", speed);
+
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+
+	/* Write all eraseblocks, 1 page at a time */
+	pr_info("testing page write speed\n");
+	start_timing();
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = write_eraseblock_by_page(i);
+		if (err)
+			goto out;
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	stop_timing();
+	speed = calc_speed();
+	pr_info("page write speed is %ld KiB/s\n", speed);
+
+	/* Read all eraseblocks, 1 page at a time */
+	pr_info("testing page read speed\n");
+	start_timing();
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = read_eraseblock_by_page(i);
+		if (err)
+			goto out;
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	stop_timing();
+	speed = calc_speed();
+	pr_info("page read speed is %ld KiB/s\n", speed);
+
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+
+	/* Write all eraseblocks, 2 pages at a time */
+	pr_info("testing 2 page write speed\n");
+	start_timing();
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = write_eraseblock_by_2pages(i);
+		if (err)
+			goto out;
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	stop_timing();
+	speed = calc_speed();
+	pr_info("2 page write speed is %ld KiB/s\n", speed);
+
+	/* Read all eraseblocks, 2 pages at a time */
+	pr_info("testing 2 page read speed\n");
+	start_timing();
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = read_eraseblock_by_2pages(i);
+		if (err)
+			goto out;
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	stop_timing();
+	speed = calc_speed();
+	pr_info("2 page read speed is %ld KiB/s\n", speed);
+
+	/* Erase all eraseblocks */
+	pr_info("Testing erase speed\n");
+	start_timing();
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+	stop_timing();
+	speed = calc_speed();
+	pr_info("erase speed is %ld KiB/s\n", speed);
+
+	/* Multi-block erase all eraseblocks */
+	for (k = 1; k < 7; k++) {
+		blocks = 1 << k;
+		pr_info("Testing %dx multi-block erase speed\n",
+		       blocks);
+		start_timing();
+		for (i = 0; i < ebcnt; ) {
+			for (j = 0; j < blocks && (i + j) < ebcnt; j++)
+				if (bbt[i + j])
+					break;
+			if (j < 1) {
+				i++;
+				continue;
+			}
+			err = multiblock_erase(i, j);
+			if (err)
+				goto out;
+
+			err = mtdtest_relax();
+			if (err)
+				goto out;
+
+			i += j;
+		}
+		stop_timing();
+		speed = calc_speed();
+		pr_info("%dx multi-block erase speed is %ld KiB/s\n",
+		       blocks, speed);
+	}
+	pr_info("finished\n");
+out:
+	kfree(iobuf);
+	kfree(bbt);
+	put_mtd_device(mtd);
+	if (err)
+		pr_info("error %d occurred\n", err);
+	printk(KERN_INFO "=================================================\n");
+	return err;
+}
+module_init(mtd_speedtest_init);
+
+static void __exit mtd_speedtest_exit(void)
+{
+	return;
+}
+module_exit(mtd_speedtest_exit);
+
+MODULE_DESCRIPTION("Speed test module");
+MODULE_AUTHOR("Adrian Hunter");
+MODULE_LICENSE("GPL");