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, 577 insertions, 0 deletions

diff --git a/drivers/md/dm-dust.c b/drivers/md/dm-dust.c
new file mode 100644
index 000000000..954f4ec5a
--- /dev/null
+++ b/drivers/md/dm-dust.c
@@ -0,0 +1,577 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2018 Red Hat, Inc.
+ *
+ * This is a test "dust" device, which fails reads on specified
+ * sectors, emulating the behavior of a hard disk drive sending
+ * a "Read Medium Error" sense.
+ *
+ */
+
+#include <linux/device-mapper.h>
+#include <linux/module.h>
+#include <linux/rbtree.h>
+
+#define DM_MSG_PREFIX "dust"
+
+struct badblock {
+	struct rb_node node;
+	sector_t bb;
+	unsigned char wr_fail_cnt;
+};
+
+struct dust_device {
+	struct dm_dev *dev;
+	struct rb_root badblocklist;
+	unsigned long long badblock_count;
+	spinlock_t dust_lock;
+	unsigned int blksz;
+	int sect_per_block_shift;
+	unsigned int sect_per_block;
+	sector_t start;
+	bool fail_read_on_bb:1;
+	bool quiet_mode:1;
+};
+
+static struct badblock *dust_rb_search(struct rb_root *root, sector_t blk)
+{
+	struct rb_node *node = root->rb_node;
+
+	while (node) {
+		struct badblock *bblk = rb_entry(node, struct badblock, node);
+
+		if (bblk->bb > blk)
+			node = node->rb_left;
+		else if (bblk->bb < blk)
+			node = node->rb_right;
+		else
+			return bblk;
+	}
+
+	return NULL;
+}
+
+static bool dust_rb_insert(struct rb_root *root, struct badblock *new)
+{
+	struct badblock *bblk;
+	struct rb_node **link = &root->rb_node, *parent = NULL;
+	sector_t value = new->bb;
+
+	while (*link) {
+		parent = *link;
+		bblk = rb_entry(parent, struct badblock, node);
+
+		if (bblk->bb > value)
+			link = &(*link)->rb_left;
+		else if (bblk->bb < value)
+			link = &(*link)->rb_right;
+		else
+			return false;
+	}
+
+	rb_link_node(&new->node, parent, link);
+	rb_insert_color(&new->node, root);
+
+	return true;
+}
+
+static int dust_remove_block(struct dust_device *dd, unsigned long long block)
+{
+	struct badblock *bblock;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dd->dust_lock, flags);
+	bblock = dust_rb_search(&dd->badblocklist, block);
+
+	if (bblock == NULL) {
+		if (!dd->quiet_mode) {
+			DMERR("%s: block %llu not found in badblocklist",
+			      __func__, block);
+		}
+		spin_unlock_irqrestore(&dd->dust_lock, flags);
+		return -EINVAL;
+	}
+
+	rb_erase(&bblock->node, &dd->badblocklist);
+	dd->badblock_count--;
+	if (!dd->quiet_mode)
+		DMINFO("%s: badblock removed at block %llu", __func__, block);
+	kfree(bblock);
+	spin_unlock_irqrestore(&dd->dust_lock, flags);
+
+	return 0;
+}
+
+static int dust_add_block(struct dust_device *dd, unsigned long long block,
+			  unsigned char wr_fail_cnt)
+{
+	struct badblock *bblock;
+	unsigned long flags;
+
+	bblock = kmalloc_obj(*bblock);
+	if (bblock == NULL) {
+		if (!dd->quiet_mode)
+			DMERR("%s: badblock allocation failed", __func__);
+		return -ENOMEM;
+	}
+
+	spin_lock_irqsave(&dd->dust_lock, flags);
+	bblock->bb = block;
+	bblock->wr_fail_cnt = wr_fail_cnt;
+	if (!dust_rb_insert(&dd->badblocklist, bblock)) {
+		if (!dd->quiet_mode) {
+			DMERR("%s: block %llu already in badblocklist",
+			      __func__, block);
+		}
+		spin_unlock_irqrestore(&dd->dust_lock, flags);
+		kfree(bblock);
+		return -EINVAL;
+	}
+
+	dd->badblock_count++;
+	if (!dd->quiet_mode) {
+		DMINFO("%s: badblock added at block %llu with write fail count %u",
+		       __func__, block, wr_fail_cnt);
+	}
+	spin_unlock_irqrestore(&dd->dust_lock, flags);
+
+	return 0;
+}
+
+static int dust_query_block(struct dust_device *dd, unsigned long long block, char *result,
+			    unsigned int maxlen, unsigned int *sz_ptr)
+{
+	struct badblock *bblock;
+	unsigned long flags;
+	unsigned int sz = *sz_ptr;
+
+	spin_lock_irqsave(&dd->dust_lock, flags);
+	bblock = dust_rb_search(&dd->badblocklist, block);
+	if (bblock != NULL)
+		DMEMIT("%s: block %llu found in badblocklist", __func__, block);
+	else
+		DMEMIT("%s: block %llu not found in badblocklist", __func__, block);
+	spin_unlock_irqrestore(&dd->dust_lock, flags);
+
+	return 1;
+}
+
+static int __dust_map_read(struct dust_device *dd, sector_t thisblock)
+{
+	struct badblock *bblk = dust_rb_search(&dd->badblocklist, thisblock);
+
+	if (bblk)
+		return DM_MAPIO_KILL;
+
+	return DM_MAPIO_REMAPPED;
+}
+
+static int dust_map_read(struct dust_device *dd, sector_t thisblock,
+			 bool fail_read_on_bb)
+{
+	unsigned long flags;
+	int r = DM_MAPIO_REMAPPED;
+
+	if (fail_read_on_bb) {
+		thisblock >>= dd->sect_per_block_shift;
+		spin_lock_irqsave(&dd->dust_lock, flags);
+		r = __dust_map_read(dd, thisblock);
+		spin_unlock_irqrestore(&dd->dust_lock, flags);
+	}
+
+	return r;
+}
+
+static int __dust_map_write(struct dust_device *dd, sector_t thisblock)
+{
+	struct badblock *bblk = dust_rb_search(&dd->badblocklist, thisblock);
+
+	if (bblk && bblk->wr_fail_cnt > 0) {
+		bblk->wr_fail_cnt--;
+		return DM_MAPIO_KILL;
+	}
+
+	if (bblk) {
+		rb_erase(&bblk->node, &dd->badblocklist);
+		dd->badblock_count--;
+		kfree(bblk);
+		if (!dd->quiet_mode) {
+			DMINFO("block %llu removed from badblocklist by write",
+			       (unsigned long long)thisblock);
+		}
+	}
+
+	return DM_MAPIO_REMAPPED;
+}
+
+static int dust_map_write(struct dust_device *dd, sector_t thisblock,
+			  bool fail_read_on_bb)
+{
+	unsigned long flags;
+	int r = DM_MAPIO_REMAPPED;
+
+	if (fail_read_on_bb) {
+		thisblock >>= dd->sect_per_block_shift;
+		spin_lock_irqsave(&dd->dust_lock, flags);
+		r = __dust_map_write(dd, thisblock);
+		spin_unlock_irqrestore(&dd->dust_lock, flags);
+	}
+
+	return r;
+}
+
+static int dust_map(struct dm_target *ti, struct bio *bio)
+{
+	struct dust_device *dd = ti->private;
+	sector_t dust_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
+	int r;
+
+	bio_set_dev(bio, dd->dev->bdev);
+	bio->bi_iter.bi_sector = dd->start + dust_sector;
+
+	if (bio_data_dir(bio) == READ)
+		r = dust_map_read(dd, dust_sector, dd->fail_read_on_bb);
+	else
+		r = dust_map_write(dd, dust_sector, dd->fail_read_on_bb);
+
+	return r;
+}
+
+static bool __dust_clear_badblocks(struct rb_root *tree,
+				   unsigned long long count)
+{
+	struct rb_node *node = NULL, *nnode = NULL;
+
+	nnode = rb_first(tree);
+	if (nnode == NULL) {
+		BUG_ON(count != 0);
+		return false;
+	}
+
+	while (nnode) {
+		node = nnode;
+		nnode = rb_next(node);
+		rb_erase(node, tree);
+		count--;
+		kfree(node);
+	}
+	BUG_ON(count != 0);
+	BUG_ON(tree->rb_node != NULL);
+
+	return true;
+}
+
+static int dust_clear_badblocks(struct dust_device *dd, char *result, unsigned int maxlen,
+				unsigned int *sz_ptr)
+{
+	unsigned long flags;
+	struct rb_root badblocklist;
+	unsigned long long badblock_count;
+	unsigned int sz = *sz_ptr;
+
+	spin_lock_irqsave(&dd->dust_lock, flags);
+	badblocklist = dd->badblocklist;
+	badblock_count = dd->badblock_count;
+	dd->badblocklist = RB_ROOT;
+	dd->badblock_count = 0;
+	spin_unlock_irqrestore(&dd->dust_lock, flags);
+
+	if (!__dust_clear_badblocks(&badblocklist, badblock_count))
+		DMEMIT("%s: no badblocks found", __func__);
+	else
+		DMEMIT("%s: badblocks cleared", __func__);
+
+	return 1;
+}
+
+static int dust_list_badblocks(struct dust_device *dd, char *result, unsigned int maxlen,
+				unsigned int *sz_ptr)
+{
+	unsigned long flags;
+	struct rb_root badblocklist;
+	struct rb_node *node;
+	struct badblock *bblk;
+	unsigned int sz = *sz_ptr;
+	unsigned long long num = 0;
+
+	spin_lock_irqsave(&dd->dust_lock, flags);
+	badblocklist = dd->badblocklist;
+	for (node = rb_first(&badblocklist); node; node = rb_next(node)) {
+		bblk = rb_entry(node, struct badblock, node);
+		DMEMIT("%llu\n", bblk->bb);
+		num++;
+	}
+
+	spin_unlock_irqrestore(&dd->dust_lock, flags);
+	if (!num)
+		DMEMIT("No blocks in badblocklist");
+
+	return 1;
+}
+
+/*
+ * Target parameters:
+ *
+ * <device_path> <offset> <blksz>
+ *
+ * device_path: path to the block device
+ * offset: offset to data area from start of device_path
+ * blksz: block size (minimum 512, maximum 1073741824, must be a power of 2)
+ */
+static int dust_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+	struct dust_device *dd;
+	unsigned long long tmp;
+	char dummy;
+	unsigned int blksz;
+	unsigned int sect_per_block;
+	sector_t DUST_MAX_BLKSZ_SECTORS = 2097152;
+	sector_t max_block_sectors = min(ti->len, DUST_MAX_BLKSZ_SECTORS);
+
+	if (argc != 3) {
+		ti->error = "Invalid argument count";
+		return -EINVAL;
+	}
+
+	if (kstrtouint(argv[2], 10, &blksz) || !blksz) {
+		ti->error = "Invalid block size parameter";
+		return -EINVAL;
+	}
+
+	if (blksz < 512) {
+		ti->error = "Block size must be at least 512";
+		return -EINVAL;
+	}
+
+	if (!is_power_of_2(blksz)) {
+		ti->error = "Block size must be a power of 2";
+		return -EINVAL;
+	}
+
+	if (to_sector(blksz) > max_block_sectors) {
+		ti->error = "Block size is too large";
+		return -EINVAL;
+	}
+
+	sect_per_block = (blksz >> SECTOR_SHIFT);
+
+	if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1 || tmp != (sector_t)tmp) {
+		ti->error = "Invalid device offset sector";
+		return -EINVAL;
+	}
+
+	dd = kzalloc_obj(struct dust_device);
+	if (dd == NULL) {
+		ti->error = "Cannot allocate context";
+		return -ENOMEM;
+	}
+
+	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dd->dev)) {
+		ti->error = "Device lookup failed";
+		kfree(dd);
+		return -EINVAL;
+	}
+
+	dd->sect_per_block = sect_per_block;
+	dd->blksz = blksz;
+	dd->start = tmp;
+
+	dd->sect_per_block_shift = __ffs(sect_per_block);
+
+	/*
+	 * Whether to fail a read on a "bad" block.
+	 * Defaults to false; enabled later by message.
+	 */
+	dd->fail_read_on_bb = false;
+
+	/*
+	 * Initialize bad block list rbtree.
+	 */
+	dd->badblocklist = RB_ROOT;
+	dd->badblock_count = 0;
+	spin_lock_init(&dd->dust_lock);
+
+	dd->quiet_mode = false;
+
+	BUG_ON(dm_set_target_max_io_len(ti, dd->sect_per_block) != 0);
+
+	ti->num_discard_bios = 1;
+	ti->num_flush_bios = 1;
+	ti->private = dd;
+
+	return 0;
+}
+
+static void dust_dtr(struct dm_target *ti)
+{
+	struct dust_device *dd = ti->private;
+
+	__dust_clear_badblocks(&dd->badblocklist, dd->badblock_count);
+	dm_put_device(ti, dd->dev);
+	kfree(dd);
+}
+
+static int dust_message(struct dm_target *ti, unsigned int argc, char **argv,
+			char *result, unsigned int maxlen)
+{
+	struct dust_device *dd = ti->private;
+	sector_t size = dm_sector_div_up(ti->len, dd->sect_per_block);
+	bool invalid_msg = false;
+	int r = -EINVAL;
+	unsigned long long tmp, block;
+	unsigned char wr_fail_cnt;
+	unsigned int tmp_ui;
+	unsigned long flags;
+	unsigned int sz = 0;
+	char dummy;
+
+	if (argc == 1) {
+		if (!strcasecmp(argv[0], "addbadblock") ||
+		    !strcasecmp(argv[0], "removebadblock") ||
+		    !strcasecmp(argv[0], "queryblock")) {
+			DMERR("%s requires an additional argument", argv[0]);
+		} else if (!strcasecmp(argv[0], "disable")) {
+			DMINFO("disabling read failures on bad sectors");
+			dd->fail_read_on_bb = false;
+			r = 0;
+		} else if (!strcasecmp(argv[0], "enable")) {
+			DMINFO("enabling read failures on bad sectors");
+			dd->fail_read_on_bb = true;
+			r = 0;
+		} else if (!strcasecmp(argv[0], "countbadblocks")) {
+			spin_lock_irqsave(&dd->dust_lock, flags);
+			DMEMIT("countbadblocks: %llu badblock(s) found",
+			       dd->badblock_count);
+			spin_unlock_irqrestore(&dd->dust_lock, flags);
+			r = 1;
+		} else if (!strcasecmp(argv[0], "clearbadblocks")) {
+			r = dust_clear_badblocks(dd, result, maxlen, &sz);
+		} else if (!strcasecmp(argv[0], "quiet")) {
+			if (!dd->quiet_mode)
+				dd->quiet_mode = true;
+			else
+				dd->quiet_mode = false;
+			r = 0;
+		} else if (!strcasecmp(argv[0], "listbadblocks")) {
+			r = dust_list_badblocks(dd, result, maxlen, &sz);
+		} else {
+			invalid_msg = true;
+		}
+	} else if (argc == 2) {
+		if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1)
+			return r;
+
+		block = tmp;
+		if (block >= size) {
+			DMERR("selected block value out of range");
+			return r;
+		}
+
+		if (!strcasecmp(argv[0], "addbadblock"))
+			r = dust_add_block(dd, block, 0);
+		else if (!strcasecmp(argv[0], "removebadblock"))
+			r = dust_remove_block(dd, block);
+		else if (!strcasecmp(argv[0], "queryblock"))
+			r = dust_query_block(dd, block, result, maxlen, &sz);
+		else
+			invalid_msg = true;
+
+	} else if (argc == 3) {
+		if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1)
+			return r;
+
+		if (sscanf(argv[2], "%u%c", &tmp_ui, &dummy) != 1)
+			return r;
+
+		block = tmp;
+		if (tmp_ui > 255) {
+			DMERR("selected write fail count out of range");
+			return r;
+		}
+		wr_fail_cnt = tmp_ui;
+		if (block >= size) {
+			DMERR("selected block value out of range");
+			return r;
+		}
+
+		if (!strcasecmp(argv[0], "addbadblock"))
+			r = dust_add_block(dd, block, wr_fail_cnt);
+		else
+			invalid_msg = true;
+
+	} else
+		DMERR("invalid number of arguments '%d'", argc);
+
+	if (invalid_msg)
+		DMERR("unrecognized message '%s' received", argv[0]);
+
+	return r;
+}
+
+static void dust_status(struct dm_target *ti, status_type_t type,
+			unsigned int status_flags, char *result, unsigned int maxlen)
+{
+	struct dust_device *dd = ti->private;
+	unsigned int sz = 0;
+
+	switch (type) {
+	case STATUSTYPE_INFO:
+		DMEMIT("%s %s %s", dd->dev->name,
+		       dd->fail_read_on_bb ? "fail_read_on_bad_block" : "bypass",
+		       dd->quiet_mode ? "quiet" : "verbose");
+		break;
+
+	case STATUSTYPE_TABLE:
+		DMEMIT("%s %llu %u", dd->dev->name,
+		       (unsigned long long)dd->start, dd->blksz);
+		break;
+
+	case STATUSTYPE_IMA:
+		*result = '\0';
+		break;
+	}
+}
+
+static int dust_prepare_ioctl(struct dm_target *ti, struct block_device **bdev,
+			      unsigned int cmd, unsigned long arg,
+			      bool *forward)
+{
+	struct dust_device *dd = ti->private;
+	struct dm_dev *dev = dd->dev;
+
+	*bdev = dev->bdev;
+
+	/*
+	 * Only pass ioctls through if the device sizes match exactly.
+	 */
+	if (dd->start || ti->len != bdev_nr_sectors(dev->bdev))
+		return 1;
+
+	return 0;
+}
+
+static int dust_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn,
+				void *data)
+{
+	struct dust_device *dd = ti->private;
+
+	return fn(ti, dd->dev, dd->start, ti->len, data);
+}
+
+static struct target_type dust_target = {
+	.name = "dust",
+	.version = {1, 0, 0},
+	.module = THIS_MODULE,
+	.ctr = dust_ctr,
+	.dtr = dust_dtr,
+	.iterate_devices = dust_iterate_devices,
+	.map = dust_map,
+	.message = dust_message,
+	.status = dust_status,
+	.prepare_ioctl = dust_prepare_ioctl,
+};
+module_dm(dust);
+
+MODULE_DESCRIPTION(DM_NAME " dust test target");
+MODULE_AUTHOR("Bryan Gurney <dm-devel@lists.linux.dev>");
+MODULE_LICENSE("GPL");