Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 532 insertions, 0 deletions

diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
new file mode 100644
index 000000000..03e80b2c4
--- /dev/null
+++ b/drivers/mtd/devices/block2mtd.c
@@ -0,0 +1,532 @@
+/*
+ * block2mtd.c - create an mtd from a block device
+ *
+ * Copyright (C) 2001,2002	Simon Evans <spse@secret.org.uk>
+ * Copyright (C) 2004-2006	Joern Engel <joern@wh.fh-wedel.de>
+ *
+ * Licence: GPL
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+/*
+ * When the first attempt at device initialization fails, we may need to
+ * wait a little bit and retry. This timeout, by default 3 seconds, gives
+ * device time to start up. Required on BCM2708 and a few other chipsets.
+ */
+#define MTD_DEFAULT_TIMEOUT	3
+
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/blkdev.h>
+#include <linux/backing-dev.h>
+#include <linux/bio.h>
+#include <linux/pagemap.h>
+#include <linux/list.h>
+#include <linux/init.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mutex.h>
+#include <linux/mount.h>
+#include <linux/slab.h>
+#include <linux/major.h>
+
+/* Maximum number of comma-separated items in the 'block2mtd=' parameter */
+#define BLOCK2MTD_PARAM_MAX_COUNT 3
+
+/* Info for the block device */
+struct block2mtd_dev {
+	struct list_head list;
+	struct file *bdev_file;
+	struct mtd_info mtd;
+	struct mutex write_mutex;
+};
+
+
+/* Static info about the MTD, used in cleanup_module */
+static LIST_HEAD(blkmtd_device_list);
+
+
+static struct page *page_read(struct address_space *mapping, pgoff_t index)
+{
+	return read_mapping_page(mapping, index, NULL);
+}
+
+/* erase a specified part of the device */
+static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len)
+{
+	struct address_space *mapping = dev->bdev_file->f_mapping;
+	struct page *page;
+	pgoff_t index = to >> PAGE_SHIFT;	// page index
+	int pages = len >> PAGE_SHIFT;
+	u_long *p;
+	u_long *max;
+
+	while (pages) {
+		page = page_read(mapping, index);
+		if (IS_ERR(page))
+			return PTR_ERR(page);
+
+		max = page_address(page) + PAGE_SIZE;
+		for (p=page_address(page); p<max; p++)
+			if (*p != -1UL) {
+				lock_page(page);
+				memset(page_address(page), 0xff, PAGE_SIZE);
+				set_page_dirty(page);
+				unlock_page(page);
+				balance_dirty_pages_ratelimited(mapping);
+				break;
+			}
+
+		put_page(page);
+		pages--;
+		index++;
+	}
+	return 0;
+}
+static int block2mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
+{
+	struct block2mtd_dev *dev = mtd->priv;
+	size_t from = instr->addr;
+	size_t len = instr->len;
+	int err;
+
+	mutex_lock(&dev->write_mutex);
+	err = _block2mtd_erase(dev, from, len);
+	mutex_unlock(&dev->write_mutex);
+	if (err)
+		pr_err("erase failed err = %d\n", err);
+
+	return err;
+}
+
+
+static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
+		size_t *retlen, u_char *buf)
+{
+	struct block2mtd_dev *dev = mtd->priv;
+	struct address_space *mapping = dev->bdev_file->f_mapping;
+	struct page *page;
+	pgoff_t index = from >> PAGE_SHIFT;
+	int offset = from & (PAGE_SIZE-1);
+	int cpylen;
+
+	while (len) {
+		if ((offset + len) > PAGE_SIZE)
+			cpylen = PAGE_SIZE - offset;	// multiple pages
+		else
+			cpylen = len;	// this page
+		len = len - cpylen;
+
+		page = page_read(mapping, index);
+		if (IS_ERR(page))
+			return PTR_ERR(page);
+
+		memcpy(buf, page_address(page) + offset, cpylen);
+		put_page(page);
+
+		if (retlen)
+			*retlen += cpylen;
+		buf += cpylen;
+		offset = 0;
+		index++;
+	}
+	return 0;
+}
+
+
+/* write data to the underlying device */
+static int _block2mtd_write(struct block2mtd_dev *dev, const u_char *buf,
+		loff_t to, size_t len, size_t *retlen)
+{
+	struct page *page;
+	struct address_space *mapping = dev->bdev_file->f_mapping;
+	pgoff_t index = to >> PAGE_SHIFT;	// page index
+	int offset = to & ~PAGE_MASK;	// page offset
+	int cpylen;
+
+	while (len) {
+		if ((offset+len) > PAGE_SIZE)
+			cpylen = PAGE_SIZE - offset;	// multiple pages
+		else
+			cpylen = len;			// this page
+		len = len - cpylen;
+
+		page = page_read(mapping, index);
+		if (IS_ERR(page))
+			return PTR_ERR(page);
+
+		if (memcmp(page_address(page)+offset, buf, cpylen)) {
+			lock_page(page);
+			memcpy(page_address(page) + offset, buf, cpylen);
+			set_page_dirty(page);
+			unlock_page(page);
+			balance_dirty_pages_ratelimited(mapping);
+		}
+		put_page(page);
+
+		if (retlen)
+			*retlen += cpylen;
+
+		buf += cpylen;
+		offset = 0;
+		index++;
+	}
+	return 0;
+}
+
+
+static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
+		size_t *retlen, const u_char *buf)
+{
+	struct block2mtd_dev *dev = mtd->priv;
+	int err;
+
+	mutex_lock(&dev->write_mutex);
+	err = _block2mtd_write(dev, buf, to, len, retlen);
+	mutex_unlock(&dev->write_mutex);
+	if (err > 0)
+		err = 0;
+	return err;
+}
+
+
+/* sync the device - wait until the write queue is empty */
+static void block2mtd_sync(struct mtd_info *mtd)
+{
+	struct block2mtd_dev *dev = mtd->priv;
+	sync_blockdev(file_bdev(dev->bdev_file));
+	return;
+}
+
+
+static void block2mtd_free_device(struct block2mtd_dev *dev)
+{
+	if (!dev)
+		return;
+
+	kfree(dev->mtd.name);
+
+	if (dev->bdev_file) {
+		invalidate_mapping_pages(dev->bdev_file->f_mapping, 0, -1);
+		bdev_fput(dev->bdev_file);
+	}
+
+	kfree(dev);
+}
+
+/*
+ * This function is marked __ref because it calls the __init marked
+ * early_lookup_bdev when called from the early boot code.
+ */
+static struct file __ref *mdtblock_early_get_bdev(const char *devname,
+		blk_mode_t mode, int timeout, struct block2mtd_dev *dev)
+{
+	struct file *bdev_file = ERR_PTR(-ENODEV);
+#ifndef MODULE
+	int i;
+
+	/*
+	 * We can't use early_lookup_bdev from a running system.
+	 */
+	if (system_state >= SYSTEM_RUNNING)
+		return bdev_file;
+
+	/*
+	 * We might not have the root device mounted at this point.
+	 * Try to resolve the device name by other means.
+	 */
+	for (i = 0; i <= timeout; i++) {
+		dev_t devt;
+
+		if (i)
+			/*
+			 * Calling wait_for_device_probe in the first loop
+			 * was not enough, sleep for a bit in subsequent
+			 * go-arounds.
+			 */
+			msleep(1000);
+		wait_for_device_probe();
+
+		if (!early_lookup_bdev(devname, &devt)) {
+			bdev_file = bdev_file_open_by_dev(devt, mode, dev, NULL);
+			if (!IS_ERR(bdev_file))
+				break;
+		}
+	}
+#endif
+	return bdev_file;
+}
+
+static struct block2mtd_dev *add_device(char *devname, int erase_size,
+		char *label, int timeout)
+{
+	const blk_mode_t mode = BLK_OPEN_READ | BLK_OPEN_WRITE;
+	struct file *bdev_file;
+	struct block_device *bdev;
+	struct block2mtd_dev *dev;
+	loff_t size;
+	char *name;
+
+	if (!devname)
+		return NULL;
+
+	dev = kzalloc_obj(struct block2mtd_dev);
+	if (!dev)
+		return NULL;
+
+	/* Get a handle on the device */
+	bdev_file = bdev_file_open_by_path(devname, mode, dev, NULL);
+	if (IS_ERR(bdev_file))
+		bdev_file = mdtblock_early_get_bdev(devname, mode, timeout,
+						      dev);
+	if (IS_ERR(bdev_file)) {
+		pr_err("error: cannot open device %s\n", devname);
+		goto err_free_block2mtd;
+	}
+	dev->bdev_file = bdev_file;
+	bdev = file_bdev(bdev_file);
+
+	if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
+		pr_err("attempting to use an MTD device as a block device\n");
+		goto err_free_block2mtd;
+	}
+
+	size = bdev_nr_bytes(bdev);
+	if ((long)size % erase_size) {
+		pr_err("erasesize must be a divisor of device size\n");
+		goto err_free_block2mtd;
+	}
+
+	mutex_init(&dev->write_mutex);
+
+	/* Setup the MTD structure */
+	/* make the name contain the block device in */
+	if (!label)
+		name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname);
+	else
+		name = kstrdup(label, GFP_KERNEL);
+	if (!name)
+		goto err_destroy_mutex;
+
+	dev->mtd.name = name;
+
+	dev->mtd.size = size & PAGE_MASK;
+	dev->mtd.erasesize = erase_size;
+	dev->mtd.writesize = 1;
+	dev->mtd.writebufsize = PAGE_SIZE;
+	dev->mtd.type = MTD_RAM;
+	dev->mtd.flags = MTD_CAP_RAM;
+	dev->mtd._erase = block2mtd_erase;
+	dev->mtd._write = block2mtd_write;
+	dev->mtd._sync = block2mtd_sync;
+	dev->mtd._read = block2mtd_read;
+	dev->mtd.priv = dev;
+	dev->mtd.owner = THIS_MODULE;
+
+	if (mtd_device_register(&dev->mtd, NULL, 0)) {
+		/* Device didn't get added, so free the entry */
+		goto err_destroy_mutex;
+	}
+
+	list_add(&dev->list, &blkmtd_device_list);
+	pr_info("mtd%d: [%s] erase_size = %dKiB [%d]\n",
+		dev->mtd.index,
+		label ? label : dev->mtd.name + strlen("block2mtd: "),
+		dev->mtd.erasesize >> 10, dev->mtd.erasesize);
+	return dev;
+
+err_destroy_mutex:
+	mutex_destroy(&dev->write_mutex);
+err_free_block2mtd:
+	block2mtd_free_device(dev);
+	return NULL;
+}
+
+
+/* This function works similar to reguler strtoul.  In addition, it
+ * allows some suffixes for a more human-readable number format:
+ * ki, Ki, kiB, KiB	- multiply result with 1024
+ * Mi, MiB		- multiply result with 1024^2
+ * Gi, GiB		- multiply result with 1024^3
+ */
+static int ustrtoul(const char *cp, char **endp, unsigned int base)
+{
+	unsigned long result = simple_strtoul(cp, endp, base);
+	switch (**endp) {
+	case 'G' :
+		result *= 1024;
+		fallthrough;
+	case 'M':
+		result *= 1024;
+		fallthrough;
+	case 'K':
+	case 'k':
+		result *= 1024;
+	/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
+		if ((*endp)[1] == 'i') {
+			if ((*endp)[2] == 'B')
+				(*endp) += 3;
+			else
+				(*endp) += 2;
+		}
+	}
+	return result;
+}
+
+
+static int parse_num(size_t *num, const char *token)
+{
+	char *endp;
+	size_t n;
+
+	n = (size_t) ustrtoul(token, &endp, 0);
+	if (*endp)
+		return -EINVAL;
+
+	*num = n;
+	return 0;
+}
+
+
+static inline void kill_final_newline(char *str)
+{
+	char *newline = strrchr(str, '\n');
+	if (newline && !newline[1])
+		*newline = 0;
+}
+
+
+#ifndef MODULE
+static int block2mtd_init_called = 0;
+/* 80 for device, 12 for erase size */
+static char block2mtd_paramline[80 + 12];
+#endif
+
+static int block2mtd_setup2(const char *val)
+{
+	/* 80 for device, 12 for erase size, 80 for name, 8 for timeout */
+	char buf[80 + 12 + 80 + 8];
+	char *str = buf;
+	char *token[BLOCK2MTD_PARAM_MAX_COUNT];
+	char *name;
+	char *label = NULL;
+	size_t erase_size = PAGE_SIZE;
+	unsigned long timeout = MTD_DEFAULT_TIMEOUT;
+	int i, ret;
+
+	if (strnlen(val, sizeof(buf)) >= sizeof(buf)) {
+		pr_err("parameter too long\n");
+		return 0;
+	}
+
+	strcpy(str, val);
+	kill_final_newline(str);
+
+	for (i = 0; i < BLOCK2MTD_PARAM_MAX_COUNT; i++)
+		token[i] = strsep(&str, ",");
+
+	if (str) {
+		pr_err("too many arguments\n");
+		return 0;
+	}
+
+	if (!token[0]) {
+		pr_err("no argument\n");
+		return 0;
+	}
+
+	name = token[0];
+	if (strlen(name) + 1 > 80) {
+		pr_err("device name too long\n");
+		return 0;
+	}
+
+	/* Optional argument when custom label is used */
+	if (token[1] && strlen(token[1])) {
+		ret = parse_num(&erase_size, token[1]);
+		if (ret) {
+			pr_err("illegal erase size\n");
+			return 0;
+		}
+	}
+
+	if (token[2]) {
+		label = token[2];
+		pr_info("Using custom MTD label '%s' for dev %s\n", label, name);
+	}
+
+	add_device(name, erase_size, label, timeout);
+
+	return 0;
+}
+
+
+static int block2mtd_setup(const char *val, const struct kernel_param *kp)
+{
+#ifdef MODULE
+	return block2mtd_setup2(val);
+#else
+	/* If more parameters are later passed in via
+	   /sys/module/block2mtd/parameters/block2mtd
+	   and block2mtd_init() has already been called,
+	   we can parse the argument now. */
+
+	if (block2mtd_init_called)
+		return block2mtd_setup2(val);
+
+	/* During early boot stage, we only save the parameters
+	   here. We must parse them later: if the param passed
+	   from kernel boot command line, block2mtd_setup() is
+	   called so early that it is not possible to resolve
+	   the device (even kmalloc() fails). Deter that work to
+	   block2mtd_setup2(). */
+
+	strscpy(block2mtd_paramline, val, sizeof(block2mtd_paramline));
+
+	return 0;
+#endif
+}
+
+
+module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200);
+MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,[<erasesize>][,<label>]]\"");
+
+static int __init block2mtd_init(void)
+{
+	int ret = 0;
+
+#ifndef MODULE
+	if (strlen(block2mtd_paramline))
+		ret = block2mtd_setup2(block2mtd_paramline);
+	block2mtd_init_called = 1;
+#endif
+
+	return ret;
+}
+
+
+static void block2mtd_exit(void)
+{
+	struct list_head *pos, *next;
+
+	/* Remove the MTD devices */
+	list_for_each_safe(pos, next, &blkmtd_device_list) {
+		struct block2mtd_dev *dev = list_entry(pos, typeof(*dev), list);
+		block2mtd_sync(&dev->mtd);
+		mtd_device_unregister(&dev->mtd);
+		mutex_destroy(&dev->write_mutex);
+		pr_info("mtd%d: [%s] removed\n",
+			dev->mtd.index,
+			dev->mtd.name + strlen("block2mtd: "));
+		list_del(&dev->list);
+		block2mtd_free_device(dev);
+	}
+}
+
+late_initcall(block2mtd_init);
+module_exit(block2mtd_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Joern Engel <joern@lazybastard.org>");
+MODULE_DESCRIPTION("Emulate an MTD using a block device");