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, 516 insertions, 0 deletions

diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
new file mode 100644
index 000000000..750865fd3
--- /dev/null
+++ b/drivers/md/dm-stripe.c
@@ -0,0 +1,516 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+#include <linux/device-mapper.h>
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/dax.h>
+#include <linux/slab.h>
+#include <linux/log2.h>
+
+static struct workqueue_struct *dm_stripe_wq;
+
+#define DM_MSG_PREFIX "striped"
+#define DM_IO_ERROR_THRESHOLD 15
+
+struct stripe {
+	struct dm_dev *dev;
+	sector_t physical_start;
+
+	atomic_t error_count;
+};
+
+struct stripe_c {
+	uint32_t stripes;
+	int stripes_shift;
+
+	/* The size of this target / num. stripes */
+	sector_t stripe_width;
+
+	uint32_t chunk_size;
+	int chunk_size_shift;
+
+	/* Needed for handling events */
+	struct dm_target *ti;
+
+	/* Work struct used for triggering events*/
+	struct work_struct trigger_event;
+
+	struct stripe stripe[] __counted_by(stripes);
+};
+
+/*
+ * An event is triggered whenever a drive
+ * drops out of a stripe volume.
+ */
+static void trigger_event(struct work_struct *work)
+{
+	struct stripe_c *sc = container_of(work, struct stripe_c,
+					   trigger_event);
+	dm_table_event(sc->ti->table);
+}
+
+/*
+ * Parse a single <dev> <sector> pair
+ */
+static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
+		      unsigned int stripe, char **argv)
+{
+	unsigned long long start;
+	char dummy;
+	int ret;
+
+	if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
+		return -EINVAL;
+
+	ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
+			    &sc->stripe[stripe].dev);
+	if (ret)
+		return ret;
+
+	sc->stripe[stripe].physical_start = start;
+
+	return 0;
+}
+
+/*
+ * Construct a striped mapping.
+ * <number of stripes> <chunk size> [<dev_path> <offset>]+
+ */
+static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+	struct stripe_c *sc;
+	sector_t width, tmp_len;
+	uint32_t stripes;
+	uint32_t chunk_size;
+	int r;
+	unsigned int i;
+
+	if (argc < 2) {
+		ti->error = "Not enough arguments";
+		return -EINVAL;
+	}
+
+	if (kstrtouint(argv[0], 10, &stripes) || !stripes) {
+		ti->error = "Invalid stripe count";
+		return -EINVAL;
+	}
+
+	if (kstrtouint(argv[1], 10, &chunk_size) || !chunk_size) {
+		ti->error = "Invalid chunk_size";
+		return -EINVAL;
+	}
+
+	width = ti->len;
+	if (sector_div(width, stripes)) {
+		ti->error = "Target length not divisible by number of stripes";
+		return -EINVAL;
+	}
+
+	tmp_len = width;
+	if (sector_div(tmp_len, chunk_size)) {
+		ti->error = "Target length not divisible by chunk size";
+		return -EINVAL;
+	}
+
+	/*
+	 * Do we have enough arguments for that many stripes ?
+	 */
+	if (argc != (2 + 2 * stripes)) {
+		ti->error = "Not enough destinations specified";
+		return -EINVAL;
+	}
+
+	sc = kmalloc_flex(*sc, stripe, stripes);
+	if (!sc) {
+		ti->error = "Memory allocation for striped context failed";
+		return -ENOMEM;
+	}
+
+	INIT_WORK(&sc->trigger_event, trigger_event);
+
+	/* Set pointer to dm target; used in trigger_event */
+	sc->ti = ti;
+	sc->stripes = stripes;
+	sc->stripe_width = width;
+
+	if (stripes & (stripes - 1))
+		sc->stripes_shift = -1;
+	else
+		sc->stripes_shift = __ffs(stripes);
+
+	r = dm_set_target_max_io_len(ti, chunk_size);
+	if (r) {
+		kfree(sc);
+		return r;
+	}
+
+	ti->num_flush_bios = stripes;
+	ti->num_discard_bios = stripes;
+	ti->num_secure_erase_bios = stripes;
+	ti->num_write_zeroes_bios = stripes;
+	ti->flush_bypasses_map = true;
+
+	sc->chunk_size = chunk_size;
+	if (chunk_size & (chunk_size - 1))
+		sc->chunk_size_shift = -1;
+	else
+		sc->chunk_size_shift = __ffs(chunk_size);
+
+	/*
+	 * Get the stripe destinations.
+	 */
+	for (i = 0; i < stripes; i++) {
+		argv += 2;
+
+		r = get_stripe(ti, sc, i, argv);
+		if (r < 0) {
+			ti->error = "Couldn't parse stripe destination";
+			while (i--)
+				dm_put_device(ti, sc->stripe[i].dev);
+			kfree(sc);
+			return r;
+		}
+		atomic_set(&(sc->stripe[i].error_count), 0);
+	}
+
+	ti->private = sc;
+
+	return 0;
+}
+
+static void stripe_dtr(struct dm_target *ti)
+{
+	unsigned int i;
+	struct stripe_c *sc = ti->private;
+
+	for (i = 0; i < sc->stripes; i++)
+		dm_put_device(ti, sc->stripe[i].dev);
+
+	flush_work(&sc->trigger_event);
+	kfree(sc);
+}
+
+static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
+			      uint32_t *stripe, sector_t *result)
+{
+	sector_t chunk = dm_target_offset(sc->ti, sector);
+	sector_t chunk_offset;
+
+	if (sc->chunk_size_shift < 0)
+		chunk_offset = sector_div(chunk, sc->chunk_size);
+	else {
+		chunk_offset = chunk & (sc->chunk_size - 1);
+		chunk >>= sc->chunk_size_shift;
+	}
+
+	if (sc->stripes_shift < 0)
+		*stripe = sector_div(chunk, sc->stripes);
+	else {
+		*stripe = chunk & (sc->stripes - 1);
+		chunk >>= sc->stripes_shift;
+	}
+
+	if (sc->chunk_size_shift < 0)
+		chunk *= sc->chunk_size;
+	else
+		chunk <<= sc->chunk_size_shift;
+
+	*result = chunk + chunk_offset;
+}
+
+static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
+				    uint32_t target_stripe, sector_t *result)
+{
+	uint32_t stripe;
+
+	stripe_map_sector(sc, sector, &stripe, result);
+	if (stripe == target_stripe)
+		return;
+
+	/* round down */
+	sector = *result;
+	if (sc->chunk_size_shift < 0)
+		*result -= sector_div(sector, sc->chunk_size);
+	else
+		*result = sector & ~(sector_t)(sc->chunk_size - 1);
+
+	if (target_stripe < stripe)
+		*result += sc->chunk_size;		/* next chunk */
+}
+
+static int stripe_map_range(struct stripe_c *sc, struct bio *bio,
+			    uint32_t target_stripe)
+{
+	sector_t begin, end;
+
+	stripe_map_range_sector(sc, bio->bi_iter.bi_sector,
+				target_stripe, &begin);
+	stripe_map_range_sector(sc, bio_end_sector(bio),
+				target_stripe, &end);
+	if (begin < end) {
+		bio_set_dev(bio, sc->stripe[target_stripe].dev->bdev);
+		bio->bi_iter.bi_sector = begin +
+			sc->stripe[target_stripe].physical_start;
+		bio->bi_iter.bi_size = to_bytes(end - begin);
+		return DM_MAPIO_REMAPPED;
+	}
+
+	/* The range doesn't map to the target stripe */
+	bio_endio(bio);
+	return DM_MAPIO_SUBMITTED;
+}
+
+int stripe_map(struct dm_target *ti, struct bio *bio)
+{
+	struct stripe_c *sc = ti->private;
+	uint32_t stripe;
+	unsigned int target_bio_nr;
+
+	if (bio->bi_opf & REQ_PREFLUSH) {
+		target_bio_nr = dm_bio_get_target_bio_nr(bio);
+		BUG_ON(target_bio_nr >= sc->stripes);
+		bio_set_dev(bio, sc->stripe[target_bio_nr].dev->bdev);
+		return DM_MAPIO_REMAPPED;
+	}
+	if (unlikely(bio_op(bio) == REQ_OP_DISCARD) ||
+	    unlikely(bio_op(bio) == REQ_OP_SECURE_ERASE) ||
+	    unlikely(bio_op(bio) == REQ_OP_WRITE_ZEROES)) {
+		target_bio_nr = dm_bio_get_target_bio_nr(bio);
+		BUG_ON(target_bio_nr >= sc->stripes);
+		return stripe_map_range(sc, bio, target_bio_nr);
+	}
+
+	stripe_map_sector(sc, bio->bi_iter.bi_sector,
+			  &stripe, &bio->bi_iter.bi_sector);
+
+	bio->bi_iter.bi_sector += sc->stripe[stripe].physical_start;
+	bio_set_dev(bio, sc->stripe[stripe].dev->bdev);
+
+	return DM_MAPIO_REMAPPED;
+}
+
+#if IS_ENABLED(CONFIG_FS_DAX)
+static struct dax_device *stripe_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff)
+{
+	struct stripe_c *sc = ti->private;
+	struct block_device *bdev;
+	sector_t dev_sector;
+	uint32_t stripe;
+
+	stripe_map_sector(sc, *pgoff * PAGE_SECTORS, &stripe, &dev_sector);
+	dev_sector += sc->stripe[stripe].physical_start;
+	bdev = sc->stripe[stripe].dev->bdev;
+
+	*pgoff = (get_start_sect(bdev) + dev_sector) >> PAGE_SECTORS_SHIFT;
+	return sc->stripe[stripe].dev->dax_dev;
+}
+
+static long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
+		long nr_pages, enum dax_access_mode mode, void **kaddr,
+		unsigned long *pfn)
+{
+	struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
+
+	return dax_direct_access(dax_dev, pgoff, nr_pages, mode, kaddr, pfn);
+}
+
+static int stripe_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
+				      size_t nr_pages)
+{
+	struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
+
+	return dax_zero_page_range(dax_dev, pgoff, nr_pages);
+}
+
+static size_t stripe_dax_recovery_write(struct dm_target *ti, pgoff_t pgoff,
+		void *addr, size_t bytes, struct iov_iter *i)
+{
+	struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
+
+	return dax_recovery_write(dax_dev, pgoff, addr, bytes, i);
+}
+
+#else
+#define stripe_dax_direct_access NULL
+#define stripe_dax_zero_page_range NULL
+#define stripe_dax_recovery_write NULL
+#endif
+
+/*
+ * Stripe status:
+ *
+ * INFO
+ * #stripes [stripe_name <stripe_name>] [group word count]
+ * [error count 'A|D' <error count 'A|D'>]
+ *
+ * TABLE
+ * #stripes [stripe chunk size]
+ * [stripe_name physical_start <stripe_name physical_start>]
+ *
+ */
+
+static void stripe_status(struct dm_target *ti, status_type_t type,
+			  unsigned int status_flags, char *result, unsigned int maxlen)
+{
+	struct stripe_c *sc = ti->private;
+	unsigned int sz = 0;
+	unsigned int i;
+
+	switch (type) {
+	case STATUSTYPE_INFO:
+		DMEMIT("%d ", sc->stripes);
+		for (i = 0; i < sc->stripes; i++)
+			DMEMIT("%s ", sc->stripe[i].dev->name);
+
+		DMEMIT("1 ");
+		for (i = 0; i < sc->stripes; i++)
+			DMEMIT("%c", atomic_read(&(sc->stripe[i].error_count)) ?  'D' : 'A');
+		break;
+
+	case STATUSTYPE_TABLE:
+		DMEMIT("%d %llu", sc->stripes,
+			(unsigned long long)sc->chunk_size);
+		for (i = 0; i < sc->stripes; i++)
+			DMEMIT(" %s %llu", sc->stripe[i].dev->name,
+			    (unsigned long long)sc->stripe[i].physical_start);
+		break;
+
+	case STATUSTYPE_IMA:
+		DMEMIT_TARGET_NAME_VERSION(ti->type);
+		DMEMIT(",stripes=%d,chunk_size=%llu", sc->stripes,
+		       (unsigned long long)sc->chunk_size);
+
+		for (i = 0; i < sc->stripes; i++) {
+			DMEMIT(",stripe_%d_device_name=%s", i, sc->stripe[i].dev->name);
+			DMEMIT(",stripe_%d_physical_start=%llu", i,
+			       (unsigned long long)sc->stripe[i].physical_start);
+			DMEMIT(",stripe_%d_status=%c", i,
+			       atomic_read(&(sc->stripe[i].error_count)) ? 'D' : 'A');
+		}
+		DMEMIT(";");
+		break;
+	}
+}
+
+static int stripe_end_io(struct dm_target *ti, struct bio *bio,
+		blk_status_t *error)
+{
+	unsigned int i;
+	char major_minor[22];
+	struct stripe_c *sc = ti->private;
+
+	if (!*error)
+		return DM_ENDIO_DONE; /* I/O complete */
+
+	if (bio->bi_opf & REQ_RAHEAD)
+		return DM_ENDIO_DONE;
+
+	if (*error == BLK_STS_NOTSUPP)
+		return DM_ENDIO_DONE;
+
+	format_dev_t(major_minor, bio_dev(bio));
+
+	/*
+	 * Test to see which stripe drive triggered the event
+	 * and increment error count for all stripes on that device.
+	 * If the error count for a given device exceeds the threshold
+	 * value we will no longer trigger any further events.
+	 */
+	for (i = 0; i < sc->stripes; i++)
+		if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
+			atomic_inc(&(sc->stripe[i].error_count));
+			if (atomic_read(&(sc->stripe[i].error_count)) <
+			    DM_IO_ERROR_THRESHOLD)
+				queue_work(dm_stripe_wq, &sc->trigger_event);
+		}
+
+	return DM_ENDIO_DONE;
+}
+
+static int stripe_iterate_devices(struct dm_target *ti,
+				  iterate_devices_callout_fn fn, void *data)
+{
+	struct stripe_c *sc = ti->private;
+	int ret = 0;
+	unsigned int i = 0;
+
+	do {
+		ret = fn(ti, sc->stripe[i].dev,
+			 sc->stripe[i].physical_start,
+			 sc->stripe_width, data);
+	} while (!ret && ++i < sc->stripes);
+
+	return ret;
+}
+
+static void stripe_io_hints(struct dm_target *ti,
+			    struct queue_limits *limits)
+{
+	struct stripe_c *sc = ti->private;
+	unsigned int io_min, io_opt, max_hw_discard_sectors = limits->max_hw_discard_sectors;
+
+	limits->chunk_sectors = sc->chunk_size;
+
+	if (!check_shl_overflow(sc->chunk_size, SECTOR_SHIFT, &io_min) &&
+	    !check_mul_overflow(io_min, sc->stripes, &io_opt)) {
+		limits->io_min = io_min;
+		limits->io_opt = io_opt;
+	}
+	if (max_hw_discard_sectors >= sc->chunk_size) {
+		if (!check_mul_overflow(max_hw_discard_sectors, sc->stripes, &max_hw_discard_sectors)) {
+			max_hw_discard_sectors = rounddown(max_hw_discard_sectors,
+					sc->chunk_size * sc->stripes);
+			limits->max_hw_discard_sectors = max_hw_discard_sectors;
+		} else
+			limits->max_hw_discard_sectors = UINT_MAX >> SECTOR_SHIFT;
+	}
+}
+
+static struct target_type stripe_target = {
+	.name   = "striped",
+	.version = {1, 7, 0},
+	.features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT |
+		    DM_TARGET_ATOMIC_WRITES | DM_TARGET_PASSES_CRYPTO,
+	.module = THIS_MODULE,
+	.ctr    = stripe_ctr,
+	.dtr    = stripe_dtr,
+	.map    = stripe_map,
+	.end_io = stripe_end_io,
+	.status = stripe_status,
+	.iterate_devices = stripe_iterate_devices,
+	.io_hints = stripe_io_hints,
+	.direct_access = stripe_dax_direct_access,
+	.dax_zero_page_range = stripe_dax_zero_page_range,
+	.dax_recovery_write = stripe_dax_recovery_write,
+};
+
+int __init dm_stripe_init(void)
+{
+	int r;
+
+	dm_stripe_wq = alloc_workqueue("dm_stripe_wq", WQ_PERCPU, 0);
+	if (!dm_stripe_wq)
+		return -ENOMEM;
+	r = dm_register_target(&stripe_target);
+	if (r < 0) {
+		destroy_workqueue(dm_stripe_wq);
+		DMWARN("target registration failed");
+	}
+
+	return r;
+}
+
+void dm_stripe_exit(void)
+{
+	dm_unregister_target(&stripe_target);
+	destroy_workqueue(dm_stripe_wq);
+}