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, 434 insertions, 0 deletions

diff --git a/fs/jffs2/build.c b/fs/jffs2/build.c
new file mode 100644
index 000000000..6ae9d6fef
--- /dev/null
+++ b/fs/jffs2/build.c
@@ -0,0 +1,434 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright © 2001-2007 Red Hat, Inc.
+ * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
+ *
+ * Created by David Woodhouse <dwmw2@infradead.org>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mm.h> /* kvfree() */
+#include "nodelist.h"
+
+static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *,
+		struct jffs2_inode_cache *, struct jffs2_full_dirent **);
+
+static inline struct jffs2_inode_cache *
+first_inode_chain(int *i, struct jffs2_sb_info *c)
+{
+	for (; *i < c->inocache_hashsize; (*i)++) {
+		if (c->inocache_list[*i])
+			return c->inocache_list[*i];
+	}
+	return NULL;
+}
+
+static inline struct jffs2_inode_cache *
+next_inode(int *i, struct jffs2_inode_cache *ic, struct jffs2_sb_info *c)
+{
+	/* More in this chain? */
+	if (ic->next)
+		return ic->next;
+	(*i)++;
+	return first_inode_chain(i, c);
+}
+
+#define for_each_inode(i, c, ic)			\
+	for (i = 0, ic = first_inode_chain(&i, (c));	\
+	     ic;					\
+	     ic = next_inode(&i, ic, (c)))
+
+
+static void jffs2_build_inode_pass1(struct jffs2_sb_info *c,
+				    struct jffs2_inode_cache *ic,
+				    int *dir_hardlinks)
+{
+	struct jffs2_full_dirent *fd;
+
+	dbg_fsbuild("building directory inode #%u\n", ic->ino);
+
+	/* For each child, increase nlink */
+	for(fd = ic->scan_dents; fd; fd = fd->next) {
+		struct jffs2_inode_cache *child_ic;
+		if (!fd->ino)
+			continue;
+
+		/* we can get high latency here with huge directories */
+
+		child_ic = jffs2_get_ino_cache(c, fd->ino);
+		if (!child_ic) {
+			dbg_fsbuild("child \"%s\" (ino #%u) of dir ino #%u doesn't exist!\n",
+				  fd->name, fd->ino, ic->ino);
+			jffs2_mark_node_obsolete(c, fd->raw);
+			/* Clear the ic/raw union so it doesn't cause problems later. */
+			fd->ic = NULL;
+			continue;
+		}
+
+		/* From this point, fd->raw is no longer used so we can set fd->ic */
+		fd->ic = child_ic;
+		child_ic->pino_nlink++;
+		/* If we appear (at this stage) to have hard-linked directories,
+		 * set a flag to trigger a scan later */
+		if (fd->type == DT_DIR) {
+			child_ic->flags |= INO_FLAGS_IS_DIR;
+			if (child_ic->pino_nlink > 1)
+				*dir_hardlinks = 1;
+		}
+
+		dbg_fsbuild("increased nlink for child \"%s\" (ino #%u)\n", fd->name, fd->ino);
+		/* Can't free scan_dents so far. We might need them in pass 2 */
+	}
+}
+
+/* Scan plan:
+ - Scan physical nodes. Build map of inodes/dirents. Allocate inocaches as we go
+ - Scan directory tree from top down, setting nlink in inocaches
+ - Scan inocaches for inodes with nlink==0
+*/
+static int jffs2_build_filesystem(struct jffs2_sb_info *c)
+{
+	int ret, i, dir_hardlinks = 0;
+	struct jffs2_inode_cache *ic;
+	struct jffs2_full_dirent *fd;
+	struct jffs2_full_dirent *dead_fds = NULL;
+
+	dbg_fsbuild("build FS data structures\n");
+
+	/* First, scan the medium and build all the inode caches with
+	   lists of physical nodes */
+
+	c->flags |= JFFS2_SB_FLAG_SCANNING;
+	ret = jffs2_scan_medium(c);
+	c->flags &= ~JFFS2_SB_FLAG_SCANNING;
+	if (ret)
+		goto exit;
+
+	dbg_fsbuild("scanned flash completely\n");
+	jffs2_dbg_dump_block_lists_nolock(c);
+
+	dbg_fsbuild("pass 1 starting\n");
+	c->flags |= JFFS2_SB_FLAG_BUILDING;
+	/* Now scan the directory tree, increasing nlink according to every dirent found. */
+	for_each_inode(i, c, ic) {
+		if (ic->scan_dents) {
+			jffs2_build_inode_pass1(c, ic, &dir_hardlinks);
+			cond_resched();
+		}
+	}
+
+	dbg_fsbuild("pass 1 complete\n");
+
+	/* Next, scan for inodes with nlink == 0 and remove them. If
+	   they were directories, then decrement the nlink of their
+	   children too, and repeat the scan. As that's going to be
+	   a fairly uncommon occurrence, it's not so evil to do it this
+	   way. Recursion bad. */
+	dbg_fsbuild("pass 2 starting\n");
+
+	for_each_inode(i, c, ic) {
+		if (ic->pino_nlink)
+			continue;
+
+		jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);
+		cond_resched();
+	}
+
+	dbg_fsbuild("pass 2a starting\n");
+
+	while (dead_fds) {
+		fd = dead_fds;
+		dead_fds = fd->next;
+
+		ic = jffs2_get_ino_cache(c, fd->ino);
+
+		if (ic)
+			jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);
+		jffs2_free_full_dirent(fd);
+	}
+
+	dbg_fsbuild("pass 2a complete\n");
+
+	if (dir_hardlinks) {
+		/* If we detected directory hardlinks earlier, *hopefully*
+		 * they are gone now because some of the links were from
+		 * dead directories which still had some old dirents lying
+		 * around and not yet garbage-collected, but which have
+		 * been discarded above. So clear the pino_nlink field
+		 * in each directory, so that the final scan below can
+		 * print appropriate warnings. */
+		for_each_inode(i, c, ic) {
+			if (ic->flags & INO_FLAGS_IS_DIR)
+				ic->pino_nlink = 0;
+		}
+	}
+	dbg_fsbuild("freeing temporary data structures\n");
+
+	/* Finally, we can scan again and free the dirent structs */
+	for_each_inode(i, c, ic) {
+		while(ic->scan_dents) {
+			fd = ic->scan_dents;
+			ic->scan_dents = fd->next;
+			/* We do use the pino_nlink field to count nlink of
+			 * directories during fs build, so set it to the
+			 * parent ino# now. Now that there's hopefully only
+			 * one. */
+			if (fd->type == DT_DIR) {
+				if (!fd->ic) {
+					/* We'll have complained about it and marked the coresponding
+					   raw node obsolete already. Just skip it. */
+					continue;
+				}
+
+				/* We *have* to have set this in jffs2_build_inode_pass1() */
+				BUG_ON(!(fd->ic->flags & INO_FLAGS_IS_DIR));
+
+				/* We clear ic->pino_nlink ∀ directories' ic *only* if dir_hardlinks
+				 * is set. Otherwise, we know this should never trigger anyway, so
+				 * we don't do the check. And ic->pino_nlink still contains the nlink
+				 * value (which is 1). */
+				if (dir_hardlinks && fd->ic->pino_nlink) {
+					JFFS2_ERROR("child dir \"%s\" (ino #%u) of dir ino #%u is also hard linked from dir ino #%u\n",
+						    fd->name, fd->ino, ic->ino, fd->ic->pino_nlink);
+					/* Should we unlink it from its previous parent? */
+				}
+
+				/* For directories, ic->pino_nlink holds that parent inode # */
+				fd->ic->pino_nlink = ic->ino;
+			}
+			jffs2_free_full_dirent(fd);
+		}
+		ic->scan_dents = NULL;
+		cond_resched();
+	}
+	ret = jffs2_build_xattr_subsystem(c);
+	if (ret)
+		goto exit;
+
+	c->flags &= ~JFFS2_SB_FLAG_BUILDING;
+
+	dbg_fsbuild("FS build complete\n");
+
+	/* Rotate the lists by some number to ensure wear levelling */
+	jffs2_rotate_lists(c);
+
+	ret = 0;
+
+exit:
+	if (ret) {
+		for_each_inode(i, c, ic) {
+			while(ic->scan_dents) {
+				fd = ic->scan_dents;
+				ic->scan_dents = fd->next;
+				jffs2_free_full_dirent(fd);
+			}
+		}
+		jffs2_clear_xattr_subsystem(c);
+	}
+
+	return ret;
+}
+
+static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *c,
+					struct jffs2_inode_cache *ic,
+					struct jffs2_full_dirent **dead_fds)
+{
+	struct jffs2_raw_node_ref *raw;
+	struct jffs2_full_dirent *fd;
+
+	dbg_fsbuild("removing ino #%u with nlink == zero.\n", ic->ino);
+
+	raw = ic->nodes;
+	while (raw != (void *)ic) {
+		struct jffs2_raw_node_ref *next = raw->next_in_ino;
+		dbg_fsbuild("obsoleting node at 0x%08x\n", ref_offset(raw));
+		jffs2_mark_node_obsolete(c, raw);
+		raw = next;
+	}
+
+	if (ic->scan_dents) {
+		int whinged = 0;
+		dbg_fsbuild("inode #%u was a directory which may have children...\n", ic->ino);
+
+		while(ic->scan_dents) {
+			struct jffs2_inode_cache *child_ic;
+
+			fd = ic->scan_dents;
+			ic->scan_dents = fd->next;
+
+			if (!fd->ino) {
+				/* It's a deletion dirent. Ignore it */
+				dbg_fsbuild("child \"%s\" is a deletion dirent, skipping...\n", fd->name);
+				jffs2_free_full_dirent(fd);
+				continue;
+			}
+			if (!whinged)
+				whinged = 1;
+
+			dbg_fsbuild("removing child \"%s\", ino #%u\n", fd->name, fd->ino);
+
+			child_ic = jffs2_get_ino_cache(c, fd->ino);
+			if (!child_ic) {
+				dbg_fsbuild("cannot remove child \"%s\", ino #%u, because it doesn't exist\n",
+						fd->name, fd->ino);
+				jffs2_free_full_dirent(fd);
+				continue;
+			}
+
+			/* Reduce nlink of the child. If it's now zero, stick it on the
+			   dead_fds list to be cleaned up later. Else just free the fd */
+			child_ic->pino_nlink--;
+
+			if (!child_ic->pino_nlink) {
+				dbg_fsbuild("inode #%u (\"%s\") now has no links; adding to dead_fds list.\n",
+					  fd->ino, fd->name);
+				fd->next = *dead_fds;
+				*dead_fds = fd;
+			} else {
+				dbg_fsbuild("inode #%u (\"%s\") has now got nlink %d. Ignoring.\n",
+					  fd->ino, fd->name, child_ic->pino_nlink);
+				jffs2_free_full_dirent(fd);
+			}
+		}
+	}
+
+	/*
+	   We don't delete the inocache from the hash list and free it yet.
+	   The erase code will do that, when all the nodes are completely gone.
+	*/
+}
+
+static void jffs2_calc_trigger_levels(struct jffs2_sb_info *c)
+{
+	uint32_t size;
+
+	/* Deletion should almost _always_ be allowed. We're fairly
+	   buggered once we stop allowing people to delete stuff
+	   because there's not enough free space... */
+	c->resv_blocks_deletion = 2;
+
+	/* Be conservative about how much space we need before we allow writes.
+	   On top of that which is required for deletia, require an extra 2%
+	   of the medium to be available, for overhead caused by nodes being
+	   split across blocks, etc. */
+
+	size = c->flash_size / 50; /* 2% of flash size */
+	size += c->nr_blocks * 100; /* And 100 bytes per eraseblock */
+	size += c->sector_size - 1; /* ... and round up */
+
+	c->resv_blocks_write = c->resv_blocks_deletion + (size / c->sector_size);
+
+	/* When do we let the GC thread run in the background */
+
+	c->resv_blocks_gctrigger = c->resv_blocks_write + 1;
+
+	/* When do we allow garbage collection to merge nodes to make
+	   long-term progress at the expense of short-term space exhaustion? */
+	c->resv_blocks_gcmerge = c->resv_blocks_deletion + 1;
+
+	/* When do we allow garbage collection to eat from bad blocks rather
+	   than actually making progress? */
+	c->resv_blocks_gcbad = 0;//c->resv_blocks_deletion + 2;
+
+	/* What number of 'very dirty' eraseblocks do we allow before we
+	   trigger the GC thread even if we don't _need_ the space. When we
+	   can't mark nodes obsolete on the medium, the old dirty nodes cause
+	   performance problems because we have to inspect and discard them. */
+	c->vdirty_blocks_gctrigger = c->resv_blocks_gctrigger;
+	if (jffs2_can_mark_obsolete(c))
+		c->vdirty_blocks_gctrigger *= 10;
+
+	/* If there's less than this amount of dirty space, don't bother
+	   trying to GC to make more space. It'll be a fruitless task */
+	c->nospc_dirty_size = c->sector_size + (c->flash_size / 100);
+
+	dbg_fsbuild("trigger levels (size %d KiB, block size %d KiB, %d blocks)\n",
+		    c->flash_size / 1024, c->sector_size / 1024, c->nr_blocks);
+	dbg_fsbuild("Blocks required to allow deletion:    %d (%d KiB)\n",
+		  c->resv_blocks_deletion, c->resv_blocks_deletion*c->sector_size/1024);
+	dbg_fsbuild("Blocks required to allow writes:      %d (%d KiB)\n",
+		  c->resv_blocks_write, c->resv_blocks_write*c->sector_size/1024);
+	dbg_fsbuild("Blocks required to quiesce GC thread: %d (%d KiB)\n",
+		  c->resv_blocks_gctrigger, c->resv_blocks_gctrigger*c->sector_size/1024);
+	dbg_fsbuild("Blocks required to allow GC merges:   %d (%d KiB)\n",
+		  c->resv_blocks_gcmerge, c->resv_blocks_gcmerge*c->sector_size/1024);
+	dbg_fsbuild("Blocks required to GC bad blocks:     %d (%d KiB)\n",
+		  c->resv_blocks_gcbad, c->resv_blocks_gcbad*c->sector_size/1024);
+	dbg_fsbuild("Amount of dirty space required to GC: %d bytes\n",
+		  c->nospc_dirty_size);
+	dbg_fsbuild("Very dirty blocks before GC triggered: %d\n",
+		  c->vdirty_blocks_gctrigger);
+}
+
+int jffs2_do_mount_fs(struct jffs2_sb_info *c)
+{
+	int ret;
+	int i;
+	int size;
+
+	c->free_size = c->flash_size;
+	c->nr_blocks = c->flash_size / c->sector_size;
+	size = sizeof(struct jffs2_eraseblock) * c->nr_blocks;
+#ifndef __ECOS
+	if (jffs2_blocks_use_vmalloc(c))
+		c->blocks = vzalloc(size);
+	else
+#endif
+		c->blocks = kzalloc(size, GFP_KERNEL);
+	if (!c->blocks)
+		return -ENOMEM;
+
+	for (i=0; i<c->nr_blocks; i++) {
+		INIT_LIST_HEAD(&c->blocks[i].list);
+		c->blocks[i].offset = i * c->sector_size;
+		c->blocks[i].free_size = c->sector_size;
+	}
+
+	INIT_LIST_HEAD(&c->clean_list);
+	INIT_LIST_HEAD(&c->very_dirty_list);
+	INIT_LIST_HEAD(&c->dirty_list);
+	INIT_LIST_HEAD(&c->erasable_list);
+	INIT_LIST_HEAD(&c->erasing_list);
+	INIT_LIST_HEAD(&c->erase_checking_list);
+	INIT_LIST_HEAD(&c->erase_pending_list);
+	INIT_LIST_HEAD(&c->erasable_pending_wbuf_list);
+	INIT_LIST_HEAD(&c->erase_complete_list);
+	INIT_LIST_HEAD(&c->free_list);
+	INIT_LIST_HEAD(&c->bad_list);
+	INIT_LIST_HEAD(&c->bad_used_list);
+	c->highest_ino = 1;
+	c->summary = NULL;
+
+	ret = jffs2_sum_init(c);
+	if (ret)
+		goto out_free;
+
+	if (jffs2_build_filesystem(c)) {
+		dbg_fsbuild("build_fs failed\n");
+		jffs2_free_ino_caches(c);
+		jffs2_free_raw_node_refs(c);
+		ret = -EIO;
+		goto out_sum_exit;
+	}
+
+	jffs2_calc_trigger_levels(c);
+
+	return 0;
+
+ out_sum_exit:
+	jffs2_sum_exit(c);
+ out_free:
+	kvfree(c->blocks);
+
+	return ret;
+}