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, 475 insertions, 0 deletions

diff --git a/fs/openpromfs/inode.c b/fs/openpromfs/inode.c
new file mode 100644
index 000000000..fb8d84bde
--- /dev/null
+++ b/fs/openpromfs/inode.c
@@ -0,0 +1,475 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* inode.c: /proc/openprom handling routines
+ *
+ * Copyright (C) 1996-1999 Jakub Jelinek  (jakub@redhat.com)
+ * Copyright (C) 1998      Eddie C. Dost  (ecd@skynet.be)
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/fs_context.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/magic.h>
+
+#include <asm/openprom.h>
+#include <asm/oplib.h>
+#include <asm/prom.h>
+#include <linux/uaccess.h>
+
+static DEFINE_MUTEX(op_mutex);
+
+#define OPENPROM_ROOT_INO	0
+
+enum op_inode_type {
+	op_inode_node,
+	op_inode_prop,
+};
+
+union op_inode_data {
+	struct device_node	*node;
+	struct property		*prop;
+};
+
+struct op_inode_info {
+	struct inode		vfs_inode;
+	enum op_inode_type	type;
+	union op_inode_data	u;
+};
+
+static struct inode *openprom_iget(struct super_block *sb, ino_t ino);
+
+static inline struct op_inode_info *OP_I(struct inode *inode)
+{
+	return container_of(inode, struct op_inode_info, vfs_inode);
+}
+
+static int is_string(unsigned char *p, int len)
+{
+	int i;
+
+	for (i = 0; i < len; i++) {
+		unsigned char val = p[i];
+
+		if ((i && !val) ||
+		    (val >= ' ' && val <= '~'))
+			continue;
+
+		return 0;
+	}
+
+	return 1;
+}
+
+static int property_show(struct seq_file *f, void *v)
+{
+	struct property *prop = f->private;
+	void *pval;
+	int len;
+
+	len = prop->length;
+	pval = prop->value;
+
+	if (is_string(pval, len)) {
+		while (len > 0) {
+			int n = strlen(pval);
+
+			seq_printf(f, "%s", (char *) pval);
+
+			/* Skip over the NULL byte too.  */
+			pval += n + 1;
+			len -= n + 1;
+
+			if (len > 0)
+				seq_printf(f, " + ");
+		}
+	} else {
+		if (len & 3) {
+			while (len) {
+				len--;
+				if (len)
+					seq_printf(f, "%02x.",
+						   *(unsigned char *) pval);
+				else
+					seq_printf(f, "%02x",
+						   *(unsigned char *) pval);
+				pval++;
+			}
+		} else {
+			while (len >= 4) {
+				len -= 4;
+
+				if (len)
+					seq_printf(f, "%08x.",
+						   *(unsigned int *) pval);
+				else
+					seq_printf(f, "%08x",
+						   *(unsigned int *) pval);
+				pval += 4;
+			}
+		}
+	}
+	seq_printf(f, "\n");
+
+	return 0;
+}
+
+static void *property_start(struct seq_file *f, loff_t *pos)
+{
+	if (*pos == 0)
+		return pos;
+	return NULL;
+}
+
+static void *property_next(struct seq_file *f, void *v, loff_t *pos)
+{
+	(*pos)++;
+	return NULL;
+}
+
+static void property_stop(struct seq_file *f, void *v)
+{
+	/* Nothing to do */
+}
+
+static const struct seq_operations property_op = {
+	.start		= property_start,
+	.next		= property_next,
+	.stop		= property_stop,
+	.show		= property_show
+};
+
+static int property_open(struct inode *inode, struct file *file)
+{
+	struct op_inode_info *oi = OP_I(inode);
+	int ret;
+
+	BUG_ON(oi->type != op_inode_prop);
+
+	ret = seq_open(file, &property_op);
+	if (!ret) {
+		struct seq_file *m = file->private_data;
+		m->private = oi->u.prop;
+	}
+	return ret;
+}
+
+static const struct file_operations openpromfs_prop_ops = {
+	.open		= property_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static int openpromfs_readdir(struct file *, struct dir_context *);
+
+static const struct file_operations openprom_operations = {
+	.read		= generic_read_dir,
+	.iterate_shared	= openpromfs_readdir,
+	.llseek		= generic_file_llseek,
+};
+
+static struct dentry *openpromfs_lookup(struct inode *, struct dentry *, unsigned int);
+
+static const struct inode_operations openprom_inode_operations = {
+	.lookup		= openpromfs_lookup,
+};
+
+static struct dentry *openpromfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
+{
+	struct op_inode_info *ent_oi, *oi = OP_I(dir);
+	struct device_node *dp, *child;
+	struct property *prop;
+	enum op_inode_type ent_type;
+	union op_inode_data ent_data;
+	const char *name;
+	struct inode *inode;
+	unsigned int ino;
+	int len;
+	
+	BUG_ON(oi->type != op_inode_node);
+
+	dp = oi->u.node;
+
+	name = dentry->d_name.name;
+	len = dentry->d_name.len;
+
+	mutex_lock(&op_mutex);
+
+	child = dp->child;
+	while (child) {
+		const char *node_name = kbasename(child->full_name);
+		int n = strlen(node_name);
+
+		if (len == n &&
+		    !strncmp(node_name, name, len)) {
+			ent_type = op_inode_node;
+			ent_data.node = child;
+			ino = child->unique_id;
+			goto found;
+		}
+		child = child->sibling;
+	}
+
+	prop = dp->properties;
+	while (prop) {
+		int n = strlen(prop->name);
+
+		if (len == n && !strncmp(prop->name, name, len)) {
+			ent_type = op_inode_prop;
+			ent_data.prop = prop;
+			ino = prop->unique_id;
+			goto found;
+		}
+
+		prop = prop->next;
+	}
+
+	mutex_unlock(&op_mutex);
+	return ERR_PTR(-ENOENT);
+
+found:
+	inode = openprom_iget(dir->i_sb, ino);
+	mutex_unlock(&op_mutex);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+	if (inode_state_read_once(inode) & I_NEW) {
+		simple_inode_init_ts(inode);
+		ent_oi = OP_I(inode);
+		ent_oi->type = ent_type;
+		ent_oi->u = ent_data;
+
+		switch (ent_type) {
+		case op_inode_node:
+			inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
+			inode->i_op = &openprom_inode_operations;
+			inode->i_fop = &openprom_operations;
+			set_nlink(inode, 2);
+			break;
+		case op_inode_prop:
+			if (of_node_name_eq(dp, "options") && (len == 17) &&
+			    !strncmp (name, "security-password", 17))
+				inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
+			else
+				inode->i_mode = S_IFREG | S_IRUGO;
+			inode->i_fop = &openpromfs_prop_ops;
+			set_nlink(inode, 1);
+			inode->i_size = ent_oi->u.prop->length;
+			break;
+		}
+		unlock_new_inode(inode);
+	}
+
+	return d_splice_alias(inode, dentry);
+}
+
+static int openpromfs_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct inode *inode = file_inode(file);
+	struct op_inode_info *oi = OP_I(inode);
+	struct device_node *dp = oi->u.node;
+	struct device_node *child;
+	struct property *prop;
+	int i;
+
+	mutex_lock(&op_mutex);
+	
+	if (ctx->pos == 0) {
+		if (!dir_emit(ctx, ".", 1, inode->i_ino, DT_DIR))
+			goto out;
+		ctx->pos = 1;
+	}
+	if (ctx->pos == 1) {
+		if (!dir_emit(ctx, "..", 2,
+			    (dp->parent == NULL ?
+			     OPENPROM_ROOT_INO :
+			     dp->parent->unique_id), DT_DIR))
+			goto out;
+		ctx->pos = 2;
+	}
+	i = ctx->pos - 2;
+
+	/* First, the children nodes as directories.  */
+	child = dp->child;
+	while (i && child) {
+		child = child->sibling;
+		i--;
+	}
+	while (child) {
+		if (!dir_emit(ctx,
+			    kbasename(child->full_name),
+			    strlen(kbasename(child->full_name)),
+			    child->unique_id, DT_DIR))
+			goto out;
+
+		ctx->pos++;
+		child = child->sibling;
+	}
+
+	/* Next, the properties as files.  */
+	prop = dp->properties;
+	while (i && prop) {
+		prop = prop->next;
+		i--;
+	}
+	while (prop) {
+		if (!dir_emit(ctx, prop->name, strlen(prop->name),
+			    prop->unique_id, DT_REG))
+			goto out;
+
+		ctx->pos++;
+		prop = prop->next;
+	}
+
+out:
+	mutex_unlock(&op_mutex);
+	return 0;
+}
+
+static struct kmem_cache *op_inode_cachep;
+
+static struct inode *openprom_alloc_inode(struct super_block *sb)
+{
+	struct op_inode_info *oi;
+
+	oi = alloc_inode_sb(sb, op_inode_cachep, GFP_KERNEL);
+	if (!oi)
+		return NULL;
+
+	return &oi->vfs_inode;
+}
+
+static void openprom_free_inode(struct inode *inode)
+{
+	kmem_cache_free(op_inode_cachep, OP_I(inode));
+}
+
+static struct inode *openprom_iget(struct super_block *sb, ino_t ino)
+{
+	struct inode *inode = iget_locked(sb, ino);
+	if (!inode)
+		inode = ERR_PTR(-ENOMEM);
+	return inode;
+}
+
+static int openpromfs_reconfigure(struct fs_context *fc)
+{
+	sync_filesystem(fc->root->d_sb);
+	fc->sb_flags |= SB_NOATIME;
+	return 0;
+}
+
+static const struct super_operations openprom_sops = {
+	.alloc_inode	= openprom_alloc_inode,
+	.free_inode	= openprom_free_inode,
+	.statfs		= simple_statfs,
+};
+
+static int openprom_fill_super(struct super_block *s, struct fs_context *fc)
+{
+	struct inode *root_inode;
+	struct op_inode_info *oi;
+	int ret;
+
+	s->s_flags |= SB_NOATIME;
+	s->s_blocksize = 1024;
+	s->s_blocksize_bits = 10;
+	s->s_magic = OPENPROM_SUPER_MAGIC;
+	s->s_op = &openprom_sops;
+	s->s_time_gran = 1;
+	root_inode = openprom_iget(s, OPENPROM_ROOT_INO);
+	if (IS_ERR(root_inode)) {
+		ret = PTR_ERR(root_inode);
+		goto out_no_root;
+	}
+
+	simple_inode_init_ts(root_inode);
+	root_inode->i_op = &openprom_inode_operations;
+	root_inode->i_fop = &openprom_operations;
+	root_inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
+	oi = OP_I(root_inode);
+	oi->type = op_inode_node;
+	oi->u.node = of_find_node_by_path("/");
+	unlock_new_inode(root_inode);
+
+	s->s_root = d_make_root(root_inode);
+	if (!s->s_root)
+		goto out_no_root_dentry;
+	return 0;
+
+out_no_root_dentry:
+	ret = -ENOMEM;
+out_no_root:
+	printk("openprom_fill_super: get root inode failed\n");
+	return ret;
+}
+
+static int openpromfs_get_tree(struct fs_context *fc)
+{
+	return get_tree_single(fc, openprom_fill_super);
+}
+
+static const struct fs_context_operations openpromfs_context_ops = {
+	.get_tree	= openpromfs_get_tree,
+	.reconfigure	= openpromfs_reconfigure,
+};
+
+static int openpromfs_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &openpromfs_context_ops;
+	return 0;
+}
+
+static struct file_system_type openprom_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "openpromfs",
+	.init_fs_context = openpromfs_init_fs_context,
+	.kill_sb	= kill_anon_super,
+};
+MODULE_ALIAS_FS("openpromfs");
+
+static void op_inode_init_once(void *data)
+{
+	struct op_inode_info *oi = (struct op_inode_info *) data;
+
+	inode_init_once(&oi->vfs_inode);
+}
+
+static int __init init_openprom_fs(void)
+{
+	int err;
+
+	op_inode_cachep = kmem_cache_create("op_inode_cache",
+					    sizeof(struct op_inode_info),
+					    0,
+					    (SLAB_RECLAIM_ACCOUNT |
+					     SLAB_ACCOUNT),
+					    op_inode_init_once);
+	if (!op_inode_cachep)
+		return -ENOMEM;
+
+	err = register_filesystem(&openprom_fs_type);
+	if (err)
+		kmem_cache_destroy(op_inode_cachep);
+
+	return err;
+}
+
+static void __exit exit_openprom_fs(void)
+{
+	unregister_filesystem(&openprom_fs_type);
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(op_inode_cachep);
+}
+
+module_init(init_openprom_fs)
+module_exit(exit_openprom_fs)
+MODULE_DESCRIPTION("OpenPROM filesystem support");
+MODULE_LICENSE("GPL");