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, 525 insertions, 0 deletions

diff --git a/fs/befs/datastream.c b/fs/befs/datastream.c
new file mode 100644
index 000000000..97719a7c7
--- /dev/null
+++ b/fs/befs/datastream.c
@@ -0,0 +1,525 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/befs/datastream.c
+ *
+ * Copyright (C) 2001 Will Dyson <will_dyson@pobox.com>
+ *
+ * Based on portions of file.c by Makoto Kato <m_kato@ga2.so-net.ne.jp>
+ *
+ * Many thanks to Dominic Giampaolo, author of "Practical File System
+ * Design with the Be File System", for such a helpful book.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/buffer_head.h>
+#include <linux/string.h>
+
+#include "befs.h"
+#include "datastream.h"
+#include "io.h"
+
+const befs_inode_addr BAD_IADDR = { 0, 0, 0 };
+
+static int befs_find_brun_direct(struct super_block *sb,
+				 const befs_data_stream *data,
+				 befs_blocknr_t blockno, befs_block_run *run);
+
+static int befs_find_brun_indirect(struct super_block *sb,
+				   const befs_data_stream *data,
+				   befs_blocknr_t blockno,
+				   befs_block_run *run);
+
+static int befs_find_brun_dblindirect(struct super_block *sb,
+				      const befs_data_stream *data,
+				      befs_blocknr_t blockno,
+				      befs_block_run *run);
+
+/**
+ * befs_read_datastream - get buffer_head containing data, starting from pos.
+ * @sb: Filesystem superblock
+ * @ds: datastream to find data with
+ * @pos: start of data
+ * @off: offset of data in buffer_head->b_data
+ *
+ * Returns pointer to buffer_head containing data starting with offset @off,
+ * if you don't need to know offset just set @off = NULL.
+ */
+struct buffer_head *
+befs_read_datastream(struct super_block *sb, const befs_data_stream *ds,
+		     befs_off_t pos, uint *off)
+{
+	struct buffer_head *bh;
+	befs_block_run run;
+	befs_blocknr_t block;	/* block coresponding to pos */
+
+	befs_debug(sb, "---> %s %llu", __func__, pos);
+	block = pos >> BEFS_SB(sb)->block_shift;
+	if (off)
+		*off = pos - (block << BEFS_SB(sb)->block_shift);
+
+	if (befs_fblock2brun(sb, ds, block, &run) != BEFS_OK) {
+		befs_error(sb, "BeFS: Error finding disk addr of block %lu",
+			   (unsigned long)block);
+		befs_debug(sb, "<--- %s ERROR", __func__);
+		return NULL;
+	}
+	bh = befs_bread_iaddr(sb, run);
+	if (!bh) {
+		befs_error(sb, "BeFS: Error reading block %lu from datastream",
+			   (unsigned long)block);
+		return NULL;
+	}
+
+	befs_debug(sb, "<--- %s read data, starting at %llu", __func__, pos);
+
+	return bh;
+}
+
+/**
+ * befs_fblock2brun - give back block run for fblock
+ * @sb: the superblock
+ * @data: datastream to read from
+ * @fblock: the blocknumber with the file position to find
+ * @run: The found run is passed back through this pointer
+ *
+ * Takes a file position and gives back a brun who's starting block
+ * is block number fblock of the file.
+ *
+ * Returns BEFS_OK or BEFS_ERR.
+ *
+ * Calls specialized functions for each of the three possible
+ * datastream regions.
+ */
+int
+befs_fblock2brun(struct super_block *sb, const befs_data_stream *data,
+		 befs_blocknr_t fblock, befs_block_run *run)
+{
+	int err;
+	befs_off_t pos = fblock << BEFS_SB(sb)->block_shift;
+
+	if (pos < data->max_direct_range) {
+		err = befs_find_brun_direct(sb, data, fblock, run);
+
+	} else if (pos < data->max_indirect_range) {
+		err = befs_find_brun_indirect(sb, data, fblock, run);
+
+	} else if (pos < data->max_double_indirect_range) {
+		err = befs_find_brun_dblindirect(sb, data, fblock, run);
+
+	} else {
+		befs_error(sb,
+			   "befs_fblock2brun() was asked to find block %lu, "
+			   "which is not mapped by the datastream\n",
+			   (unsigned long)fblock);
+		err = BEFS_ERR;
+	}
+	return err;
+}
+
+/**
+ * befs_read_lsmylink - read long symlink from datastream.
+ * @sb: Filesystem superblock
+ * @ds: Datastream to read from
+ * @buff: Buffer in which to place long symlink data
+ * @len: Length of the long symlink in bytes
+ *
+ * Returns the number of bytes read
+ */
+size_t
+befs_read_lsymlink(struct super_block *sb, const befs_data_stream *ds,
+		   void *buff, befs_off_t len)
+{
+	befs_off_t bytes_read = 0;	/* bytes readed */
+	u16 plen;
+	struct buffer_head *bh;
+
+	befs_debug(sb, "---> %s length: %llu", __func__, len);
+
+	while (bytes_read < len) {
+		bh = befs_read_datastream(sb, ds, bytes_read, NULL);
+		if (!bh) {
+			befs_error(sb, "BeFS: Error reading datastream block "
+				   "starting from %llu", bytes_read);
+			befs_debug(sb, "<--- %s ERROR", __func__);
+			return bytes_read;
+
+		}
+		plen = ((bytes_read + BEFS_SB(sb)->block_size) < len) ?
+		    BEFS_SB(sb)->block_size : len - bytes_read;
+		memcpy(buff + bytes_read, bh->b_data, plen);
+		brelse(bh);
+		bytes_read += plen;
+	}
+
+	befs_debug(sb, "<--- %s read %u bytes", __func__, (unsigned int)
+		   bytes_read);
+	return bytes_read;
+}
+
+/**
+ * befs_count_blocks - blocks used by a file
+ * @sb: Filesystem superblock
+ * @ds: Datastream of the file
+ *
+ * Counts the number of fs blocks that the file represented by
+ * inode occupies on the filesystem, counting both regular file
+ * data and filesystem metadata (and eventually attribute data
+ * when we support attributes)
+*/
+
+befs_blocknr_t
+befs_count_blocks(struct super_block *sb, const befs_data_stream *ds)
+{
+	befs_blocknr_t blocks;
+	befs_blocknr_t datablocks;	/* File data blocks */
+	befs_blocknr_t metablocks;	/* FS metadata blocks */
+	struct befs_sb_info *befs_sb = BEFS_SB(sb);
+
+	befs_debug(sb, "---> %s", __func__);
+
+	datablocks = ds->size >> befs_sb->block_shift;
+	if (ds->size & (befs_sb->block_size - 1))
+		datablocks += 1;
+
+	metablocks = 1;		/* Start with 1 block for inode */
+
+	/* Size of indirect block */
+	if (ds->size > ds->max_direct_range)
+		metablocks += ds->indirect.len;
+
+	/*
+	 * Double indir block, plus all the indirect blocks it maps.
+	 * In the double-indirect range, all block runs of data are
+	 * BEFS_DBLINDIR_BRUN_LEN blocks long. Therefore, we know
+	 * how many data block runs are in the double-indirect region,
+	 * and from that we know how many indirect blocks it takes to
+	 * map them. We assume that the indirect blocks are also
+	 * BEFS_DBLINDIR_BRUN_LEN blocks long.
+	 */
+	if (ds->size > ds->max_indirect_range && ds->max_indirect_range != 0) {
+		uint dbl_bytes;
+		uint dbl_bruns;
+		uint indirblocks;
+
+		dbl_bytes =
+		    ds->max_double_indirect_range - ds->max_indirect_range;
+		dbl_bruns =
+		    dbl_bytes / (befs_sb->block_size * BEFS_DBLINDIR_BRUN_LEN);
+		indirblocks = dbl_bruns / befs_iaddrs_per_block(sb);
+
+		metablocks += ds->double_indirect.len;
+		metablocks += indirblocks;
+	}
+
+	blocks = datablocks + metablocks;
+	befs_debug(sb, "<--- %s %u blocks", __func__, (unsigned int)blocks);
+
+	return blocks;
+}
+
+/**
+ * befs_find_brun_direct - find a direct block run in the datastream
+ * @sb: the superblock
+ * @data: the datastream
+ * @blockno: the blocknumber to find
+ * @run: The found run is passed back through this pointer
+ *
+ * Finds the block run that starts at file block number blockno
+ * in the file represented by the datastream data, if that
+ * blockno is in the direct region of the datastream.
+ *
+ * Return value is BEFS_OK if the blockrun is found, BEFS_ERR
+ * otherwise.
+ *
+ * Algorithm:
+ * Linear search. Checks each element of array[] to see if it
+ * contains the blockno-th filesystem block. This is necessary
+ * because the block runs map variable amounts of data. Simply
+ * keeps a count of the number of blocks searched so far (sum),
+ * incrementing this by the length of each block run as we come
+ * across it. Adds sum to *count before returning (this is so
+ * you can search multiple arrays that are logicaly one array,
+ * as in the indirect region code).
+ *
+ * When/if blockno is found, if blockno is inside of a block
+ * run as stored on disk, we offset the start and length members
+ * of the block run, so that blockno is the start and len is
+ * still valid (the run ends in the same place).
+ */
+static int
+befs_find_brun_direct(struct super_block *sb, const befs_data_stream *data,
+		      befs_blocknr_t blockno, befs_block_run *run)
+{
+	int i;
+	const befs_block_run *array = data->direct;
+	befs_blocknr_t sum;
+
+	befs_debug(sb, "---> %s, find %lu", __func__, (unsigned long)blockno);
+
+	for (i = 0, sum = 0; i < BEFS_NUM_DIRECT_BLOCKS;
+	     sum += array[i].len, i++) {
+		if (blockno >= sum && blockno < sum + (array[i].len)) {
+			int offset = blockno - sum;
+
+			run->allocation_group = array[i].allocation_group;
+			run->start = array[i].start + offset;
+			run->len = array[i].len - offset;
+
+			befs_debug(sb, "---> %s, "
+				   "found %lu at direct[%d]", __func__,
+				   (unsigned long)blockno, i);
+			return BEFS_OK;
+		}
+	}
+
+	befs_error(sb, "%s failed to find file block %lu", __func__,
+		   (unsigned long)blockno);
+	befs_debug(sb, "---> %s ERROR", __func__);
+	return BEFS_ERR;
+}
+
+/**
+ * befs_find_brun_indirect - find a block run in the datastream
+ * @sb: the superblock
+ * @data: the datastream
+ * @blockno: the blocknumber to find
+ * @run: The found run is passed back through this pointer
+ *
+ * Finds the block run that starts at file block number blockno
+ * in the file represented by the datastream data, if that
+ * blockno is in the indirect region of the datastream.
+ *
+ * Return value is BEFS_OK if the blockrun is found, BEFS_ERR
+ * otherwise.
+ *
+ * Algorithm:
+ * For each block in the indirect run of the datastream, read
+ * it in and search through it for search_blk.
+ *
+ * XXX:
+ * Really should check to make sure blockno is inside indirect
+ * region.
+ */
+static int
+befs_find_brun_indirect(struct super_block *sb,
+			const befs_data_stream *data,
+			befs_blocknr_t blockno,
+			befs_block_run *run)
+{
+	int i, j;
+	befs_blocknr_t sum = 0;
+	befs_blocknr_t indir_start_blk;
+	befs_blocknr_t search_blk;
+	struct buffer_head *indirblock;
+	befs_disk_block_run *array;
+
+	befs_block_run indirect = data->indirect;
+	befs_blocknr_t indirblockno = iaddr2blockno(sb, &indirect);
+	int arraylen = befs_iaddrs_per_block(sb);
+
+	befs_debug(sb, "---> %s, find %lu", __func__, (unsigned long)blockno);
+
+	indir_start_blk = data->max_direct_range >> BEFS_SB(sb)->block_shift;
+	search_blk = blockno - indir_start_blk;
+
+	/* Examine blocks of the indirect run one at a time */
+	for (i = 0; i < indirect.len; i++) {
+		indirblock = sb_bread(sb, indirblockno + i);
+		if (indirblock == NULL) {
+			befs_error(sb, "---> %s failed to read "
+				   "disk block %lu from the indirect brun",
+				   __func__, (unsigned long)indirblockno + i);
+			befs_debug(sb, "<--- %s ERROR", __func__);
+			return BEFS_ERR;
+		}
+
+		array = (befs_disk_block_run *) indirblock->b_data;
+
+		for (j = 0; j < arraylen; ++j) {
+			int len = fs16_to_cpu(sb, array[j].len);
+
+			if (search_blk >= sum && search_blk < sum + len) {
+				int offset = search_blk - sum;
+				run->allocation_group =
+				    fs32_to_cpu(sb, array[j].allocation_group);
+				run->start =
+				    fs16_to_cpu(sb, array[j].start) + offset;
+				run->len =
+				    fs16_to_cpu(sb, array[j].len) - offset;
+
+				brelse(indirblock);
+				befs_debug(sb,
+					   "<--- %s found file block "
+					   "%lu at indirect[%d]", __func__,
+					   (unsigned long)blockno,
+					   j + (i * arraylen));
+				return BEFS_OK;
+			}
+			sum += len;
+		}
+
+		brelse(indirblock);
+	}
+
+	/* Only fallthrough is an error */
+	befs_error(sb, "BeFS: %s failed to find "
+		   "file block %lu", __func__, (unsigned long)blockno);
+
+	befs_debug(sb, "<--- %s ERROR", __func__);
+	return BEFS_ERR;
+}
+
+/**
+ * befs_find_brun_dblindirect - find a block run in the datastream
+ * @sb: the superblock
+ * @data: the datastream
+ * @blockno: the blocknumber to find
+ * @run: The found run is passed back through this pointer
+ *
+ * Finds the block run that starts at file block number blockno
+ * in the file represented by the datastream data, if that
+ * blockno is in the double-indirect region of the datastream.
+ *
+ * Return value is BEFS_OK if the blockrun is found, BEFS_ERR
+ * otherwise.
+ *
+ * Algorithm:
+ * The block runs in the double-indirect region are different.
+ * They are always allocated 4 fs blocks at a time, so each
+ * block run maps a constant amount of file data. This means
+ * that we can directly calculate how many block runs into the
+ * double-indirect region we need to go to get to the one that
+ * maps a particular filesystem block.
+ *
+ * We do this in two stages. First we calculate which of the
+ * inode addresses in the double-indirect block will point us
+ * to the indirect block that contains the mapping for the data,
+ * then we calculate which of the inode addresses in that
+ * indirect block maps the data block we are after.
+ *
+ * Oh, and once we've done that, we actually read in the blocks
+ * that contain the inode addresses we calculated above. Even
+ * though the double-indirect run may be several blocks long,
+ * we can calculate which of those blocks will contain the index
+ * we are after and only read that one. We then follow it to
+ * the indirect block and perform a similar process to find
+ * the actual block run that maps the data block we are interested
+ * in.
+ *
+ * Then we offset the run as in befs_find_brun_array() and we are
+ * done.
+ */
+static int
+befs_find_brun_dblindirect(struct super_block *sb,
+			   const befs_data_stream *data,
+			   befs_blocknr_t blockno,
+			   befs_block_run *run)
+{
+	int dblindir_indx;
+	int indir_indx;
+	int offset;
+	int dbl_which_block;
+	int which_block;
+	int dbl_block_indx;
+	int block_indx;
+	off_t dblindir_leftover;
+	befs_blocknr_t blockno_at_run_start;
+	struct buffer_head *dbl_indir_block;
+	struct buffer_head *indir_block;
+	befs_block_run indir_run;
+	befs_disk_inode_addr *iaddr_array;
+
+	befs_blocknr_t indir_start_blk =
+	    data->max_indirect_range >> BEFS_SB(sb)->block_shift;
+
+	off_t dbl_indir_off = blockno - indir_start_blk;
+
+	/* number of data blocks mapped by each of the iaddrs in
+	 * the indirect block pointed to by the double indirect block
+	 */
+	size_t iblklen = BEFS_DBLINDIR_BRUN_LEN;
+
+	/* number of data blocks mapped by each of the iaddrs in
+	 * the double indirect block
+	 */
+	size_t diblklen = iblklen * befs_iaddrs_per_block(sb)
+	    * BEFS_DBLINDIR_BRUN_LEN;
+
+	befs_debug(sb, "---> %s find %lu", __func__, (unsigned long)blockno);
+
+	/* First, discover which of the double_indir->indir blocks
+	 * contains pos. Then figure out how much of pos that
+	 * accounted for. Then discover which of the iaddrs in
+	 * the indirect block contains pos.
+	 */
+
+	dblindir_indx = dbl_indir_off / diblklen;
+	dblindir_leftover = dbl_indir_off % diblklen;
+	indir_indx = dblindir_leftover / diblklen;
+
+	/* Read double indirect block */
+	dbl_which_block = dblindir_indx / befs_iaddrs_per_block(sb);
+	if (dbl_which_block > data->double_indirect.len) {
+		befs_error(sb, "The double-indirect index calculated by "
+			   "%s, %d, is outside the range "
+			   "of the double-indirect block", __func__,
+			   dblindir_indx);
+		return BEFS_ERR;
+	}
+
+	dbl_indir_block =
+	    sb_bread(sb, iaddr2blockno(sb, &data->double_indirect) +
+					dbl_which_block);
+	if (dbl_indir_block == NULL) {
+		befs_error(sb, "%s couldn't read the "
+			   "double-indirect block at blockno %lu", __func__,
+			   (unsigned long)
+			   iaddr2blockno(sb, &data->double_indirect) +
+			   dbl_which_block);
+		return BEFS_ERR;
+	}
+
+	dbl_block_indx =
+	    dblindir_indx - (dbl_which_block * befs_iaddrs_per_block(sb));
+	iaddr_array = (befs_disk_inode_addr *) dbl_indir_block->b_data;
+	indir_run = fsrun_to_cpu(sb, iaddr_array[dbl_block_indx]);
+	brelse(dbl_indir_block);
+
+	/* Read indirect block */
+	which_block = indir_indx / befs_iaddrs_per_block(sb);
+	if (which_block > indir_run.len) {
+		befs_error(sb, "The indirect index calculated by "
+			   "%s, %d, is outside the range "
+			   "of the indirect block", __func__, indir_indx);
+		return BEFS_ERR;
+	}
+
+	indir_block =
+	    sb_bread(sb, iaddr2blockno(sb, &indir_run) + which_block);
+	if (indir_block == NULL) {
+		befs_error(sb, "%s couldn't read the indirect block "
+			   "at blockno %lu", __func__, (unsigned long)
+			   iaddr2blockno(sb, &indir_run) + which_block);
+		return BEFS_ERR;
+	}
+
+	block_indx = indir_indx - (which_block * befs_iaddrs_per_block(sb));
+	iaddr_array = (befs_disk_inode_addr *) indir_block->b_data;
+	*run = fsrun_to_cpu(sb, iaddr_array[block_indx]);
+	brelse(indir_block);
+
+	blockno_at_run_start = indir_start_blk;
+	blockno_at_run_start += diblklen * dblindir_indx;
+	blockno_at_run_start += iblklen * indir_indx;
+	offset = blockno - blockno_at_run_start;
+
+	run->start += offset;
+	run->len -= offset;
+
+	befs_debug(sb, "Found file block %lu in double_indirect[%d][%d],"
+		   " double_indirect_leftover = %lu", (unsigned long)
+		   blockno, dblindir_indx, indir_indx, dblindir_leftover);
+
+	return BEFS_OK;
+}