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, 386 insertions, 0 deletions

diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
new file mode 100644
index 000000000..2d5850168
--- /dev/null
+++ b/fs/squashfs/block.c
@@ -0,0 +1,386 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.uk>
+ *
+ * block.c
+ */
+
+/*
+ * This file implements the low-level routines to read and decompress
+ * datablocks and metadata blocks.
+ */
+
+#include <linux/blkdev.h>
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/string.h>
+#include <linux/bio.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs.h"
+#include "decompressor.h"
+#include "page_actor.h"
+
+/*
+ * Returns the amount of bytes copied to the page actor.
+ */
+static int copy_bio_to_actor(struct bio *bio,
+			     struct squashfs_page_actor *actor,
+			     int offset, int req_length)
+{
+	void *actor_addr;
+	struct bvec_iter_all iter_all = {};
+	struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
+	int copied_bytes = 0;
+	int actor_offset = 0;
+
+	squashfs_actor_nobuff(actor);
+	actor_addr = squashfs_first_page(actor);
+
+	if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all)))
+		return 0;
+
+	while (copied_bytes < req_length) {
+		int bytes_to_copy = min_t(int, bvec->bv_len - offset,
+					  PAGE_SIZE - actor_offset);
+
+		bytes_to_copy = min_t(int, bytes_to_copy,
+				      req_length - copied_bytes);
+		if (!IS_ERR(actor_addr))
+			memcpy(actor_addr + actor_offset, bvec_virt(bvec) +
+					offset, bytes_to_copy);
+
+		actor_offset += bytes_to_copy;
+		copied_bytes += bytes_to_copy;
+		offset += bytes_to_copy;
+
+		if (actor_offset >= PAGE_SIZE) {
+			actor_addr = squashfs_next_page(actor);
+			if (!actor_addr)
+				break;
+			actor_offset = 0;
+		}
+		if (offset >= bvec->bv_len) {
+			if (!bio_next_segment(bio, &iter_all))
+				break;
+			offset = 0;
+		}
+	}
+	squashfs_finish_page(actor);
+	return copied_bytes;
+}
+
+static int squashfs_bio_read_cached(struct bio *fullbio,
+		struct address_space *cache_mapping, u64 index, int length,
+		u64 read_start, u64 read_end, int page_count)
+{
+	struct folio *head_to_cache = NULL, *tail_to_cache = NULL;
+	struct block_device *bdev = fullbio->bi_bdev;
+	int start_idx = 0, end_idx = 0;
+	struct folio_iter fi;
+	struct bio *bio = NULL;
+	int idx = 0;
+	int err = 0;
+#ifdef CONFIG_SQUASHFS_COMP_CACHE_FULL
+	struct folio **cache_folios = kmalloc_objs(*cache_folios, page_count,
+						   GFP_KERNEL | __GFP_ZERO);
+#endif
+
+	bio_for_each_folio_all(fi, fullbio) {
+		struct folio *folio = fi.folio;
+
+		if (folio->mapping == cache_mapping) {
+			idx++;
+			continue;
+		}
+
+		/*
+		 * We only use this when the device block size is the same as
+		 * the page size, so read_start and read_end cover full pages.
+		 *
+		 * Compare these to the original required index and length to
+		 * only cache pages which were requested partially, since these
+		 * are the ones which are likely to be needed when reading
+		 * adjacent blocks.
+		 */
+		if (idx == 0 && index != read_start)
+			head_to_cache = folio;
+		else if (idx == page_count - 1 && index + length != read_end)
+			tail_to_cache = folio;
+#ifdef CONFIG_SQUASHFS_COMP_CACHE_FULL
+		/* Cache all pages in the BIO for repeated reads */
+		else if (cache_folios)
+			cache_folios[idx] = folio;
+#endif
+
+		if (!bio || idx != end_idx) {
+			struct bio *new = bio_alloc_clone(bdev, fullbio,
+							  GFP_NOIO, &fs_bio_set);
+
+			if (bio) {
+				bio_trim(bio, start_idx * PAGE_SECTORS,
+					 (end_idx - start_idx) * PAGE_SECTORS);
+				bio_chain(bio, new);
+				submit_bio(bio);
+			}
+
+			bio = new;
+			start_idx = idx;
+		}
+
+		idx++;
+		end_idx = idx;
+	}
+
+	if (bio) {
+		bio_trim(bio, start_idx * PAGE_SECTORS,
+			 (end_idx - start_idx) * PAGE_SECTORS);
+		err = submit_bio_wait(bio);
+		bio_put(bio);
+	}
+
+	if (err)
+		return err;
+
+	if (head_to_cache) {
+		int ret = filemap_add_folio(cache_mapping, head_to_cache,
+						read_start >> PAGE_SHIFT,
+						GFP_NOIO);
+
+		if (!ret) {
+			folio_mark_uptodate(head_to_cache);
+			folio_unlock(head_to_cache);
+		}
+
+	}
+
+	if (tail_to_cache) {
+		int ret = filemap_add_folio(cache_mapping, tail_to_cache,
+						(read_end >> PAGE_SHIFT) - 1,
+						GFP_NOIO);
+
+		if (!ret) {
+			folio_mark_uptodate(tail_to_cache);
+			folio_unlock(tail_to_cache);
+		}
+	}
+
+#ifdef CONFIG_SQUASHFS_COMP_CACHE_FULL
+	if (!cache_folios)
+		goto out;
+
+	for (idx = 0; idx < page_count; idx++) {
+		if (!cache_folios[idx])
+			continue;
+		int ret = filemap_add_folio(cache_mapping, cache_folios[idx],
+						(read_start >> PAGE_SHIFT) + idx,
+						GFP_NOIO);
+
+		if (!ret) {
+			folio_mark_uptodate(cache_folios[idx]);
+			folio_unlock(cache_folios[idx]);
+		}
+	}
+	kfree(cache_folios);
+out:
+#endif
+	return 0;
+}
+
+static struct page *squashfs_get_cache_page(struct address_space *mapping,
+					    pgoff_t index)
+{
+	struct page *page;
+
+	if (!mapping)
+		return NULL;
+
+	page = find_get_page(mapping, index);
+	if (!page)
+		return NULL;
+
+	if (!PageUptodate(page)) {
+		put_page(page);
+		return NULL;
+	}
+
+	return page;
+}
+
+static int squashfs_bio_read(struct super_block *sb, u64 index, int length,
+			     struct bio **biop, int *block_offset)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	struct address_space *cache_mapping = msblk->cache_mapping;
+	const u64 read_start = round_down(index, msblk->devblksize);
+	const sector_t block = read_start >> msblk->devblksize_log2;
+	const u64 read_end = round_up(index + length, msblk->devblksize);
+	const sector_t block_end = read_end >> msblk->devblksize_log2;
+	int offset = read_start - round_down(index, PAGE_SIZE);
+	int total_len = (block_end - block) << msblk->devblksize_log2;
+	const int page_count = DIV_ROUND_UP(total_len + offset, PAGE_SIZE);
+	int error, i;
+	struct bio *bio;
+
+	bio = bio_kmalloc(page_count, GFP_NOIO);
+	if (!bio)
+		return -ENOMEM;
+	bio_init_inline(bio, sb->s_bdev, page_count, REQ_OP_READ);
+	bio->bi_iter.bi_sector = block * (msblk->devblksize >> SECTOR_SHIFT);
+
+	for (i = 0; i < page_count; ++i) {
+		unsigned int len =
+			min_t(unsigned int, PAGE_SIZE - offset, total_len);
+		pgoff_t index = (read_start >> PAGE_SHIFT) + i;
+		struct page *page;
+
+		page = squashfs_get_cache_page(cache_mapping, index);
+		if (!page)
+			page = alloc_page(GFP_NOIO);
+
+		if (!page) {
+			error = -ENOMEM;
+			goto out_free_bio;
+		}
+
+		/*
+		 * Use the __ version to avoid merging since we need each page
+		 * to be separate when we check for and avoid cached pages.
+		 */
+		__bio_add_page(bio, page, len, offset);
+		offset = 0;
+		total_len -= len;
+	}
+
+	if (cache_mapping)
+		error = squashfs_bio_read_cached(bio, cache_mapping, index,
+						 length, read_start, read_end,
+						 page_count);
+	else
+		error = submit_bio_wait(bio);
+	if (error)
+		goto out_free_bio;
+
+	*biop = bio;
+	*block_offset = index & ((1 << msblk->devblksize_log2) - 1);
+	return 0;
+
+out_free_bio:
+	bio_free_pages(bio);
+	bio_uninit(bio);
+	kfree(bio);
+	return error;
+}
+
+/*
+ * Read and decompress a metadata block or datablock.  Length is non-zero
+ * if a datablock is being read (the size is stored elsewhere in the
+ * filesystem), otherwise the length is obtained from the first two bytes of
+ * the metadata block.  A bit in the length field indicates if the block
+ * is stored uncompressed in the filesystem (usually because compression
+ * generated a larger block - this does occasionally happen with compression
+ * algorithms).
+ */
+int squashfs_read_data(struct super_block *sb, u64 index, int length,
+		       u64 *next_index, struct squashfs_page_actor *output)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	struct bio *bio = NULL;
+	int compressed;
+	int res;
+	int offset;
+
+	if (length) {
+		/*
+		 * Datablock.
+		 */
+		compressed = SQUASHFS_COMPRESSED_BLOCK(length);
+		length = SQUASHFS_COMPRESSED_SIZE_BLOCK(length);
+		TRACE("Block @ 0x%llx, %scompressed size %d, src size %d\n",
+			index, compressed ? "" : "un", length, output->length);
+	} else {
+		/*
+		 * Metadata block.
+		 */
+		const u8 *data;
+		struct bvec_iter_all iter_all = {};
+		struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
+
+		if (index + 2 > msblk->bytes_used) {
+			res = -EIO;
+			goto out;
+		}
+		res = squashfs_bio_read(sb, index, 2, &bio, &offset);
+		if (res)
+			goto out;
+
+		if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all))) {
+			res = -EIO;
+			goto out_free_bio;
+		}
+		/* Extract the length of the metadata block */
+		data = bvec_virt(bvec);
+		length = data[offset];
+		if (offset < bvec->bv_len - 1) {
+			length |= data[offset + 1] << 8;
+		} else {
+			if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all))) {
+				res = -EIO;
+				goto out_free_bio;
+			}
+			data = bvec_virt(bvec);
+			length |= data[0] << 8;
+		}
+		bio_free_pages(bio);
+		bio_uninit(bio);
+		kfree(bio);
+
+		compressed = SQUASHFS_COMPRESSED(length);
+		length = SQUASHFS_COMPRESSED_SIZE(length);
+		index += 2;
+
+		TRACE("Block @ 0x%llx, %scompressed size %d\n", index - 2,
+		      compressed ? "" : "un", length);
+	}
+	if (length <= 0 || length > output->length ||
+			(index + length) > msblk->bytes_used) {
+		res = -EIO;
+		goto out;
+	}
+
+	if (next_index)
+		*next_index = index + length;
+
+	res = squashfs_bio_read(sb, index, length, &bio, &offset);
+	if (res)
+		goto out;
+
+	if (compressed) {
+		if (!msblk->stream) {
+			res = -EIO;
+			goto out_free_bio;
+		}
+		res = msblk->thread_ops->decompress(msblk, bio, offset, length, output);
+	} else {
+		res = copy_bio_to_actor(bio, output, offset, length);
+	}
+
+out_free_bio:
+	bio_free_pages(bio);
+	bio_uninit(bio);
+	kfree(bio);
+out:
+	if (res < 0) {
+		ERROR("Failed to read block 0x%llx: %d\n", index, res);
+		if (msblk->panic_on_errors)
+			panic("squashfs read failed");
+	}
+
+	return res;
+}