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, 390 insertions, 0 deletions

diff --git a/fs/fs_parser.c b/fs/fs_parser.c
new file mode 100644
index 000000000..b4cc4cce5
--- /dev/null
+++ b/fs/fs_parser.c
@@ -0,0 +1,390 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Filesystem parameter parser.
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/export.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+#include <linux/slab.h>
+#include <linux/security.h>
+#include <linux/namei.h>
+#include "internal.h"
+
+static const struct constant_table bool_names[] = {
+	{ "0",		false },
+	{ "1",		true },
+	{ "false",	false },
+	{ "no",		false },
+	{ "true",	true },
+	{ "yes",	true },
+	{ },
+};
+
+static const struct constant_table *
+__lookup_constant(const struct constant_table *tbl, const char *name)
+{
+	for ( ; tbl->name; tbl++)
+		if (strcmp(name, tbl->name) == 0)
+			return tbl;
+	return NULL;
+}
+
+/**
+ * lookup_constant - Look up a constant by name in an ordered table
+ * @tbl: The table of constants to search.
+ * @name: The name to look up.
+ * @not_found: The value to return if the name is not found.
+ */
+int lookup_constant(const struct constant_table *tbl, const char *name, int not_found)
+{
+	const struct constant_table *p = __lookup_constant(tbl, name);
+
+	return p ? p->value : not_found;
+}
+EXPORT_SYMBOL(lookup_constant);
+
+static inline bool is_flag(const struct fs_parameter_spec *p)
+{
+	return p->type == NULL;
+}
+
+static const struct fs_parameter_spec *fs_lookup_key(
+	const struct fs_parameter_spec *desc,
+	struct fs_parameter *param, bool *negated)
+{
+	const struct fs_parameter_spec *p, *other = NULL;
+	const char *name = param->key;
+	bool want_flag = param->type == fs_value_is_flag;
+
+	*negated = false;
+	for (p = desc; p->name; p++) {
+		if (strcmp(p->name, name) != 0)
+			continue;
+		if (likely(is_flag(p) == want_flag))
+			return p;
+		other = p;
+	}
+	if (want_flag) {
+		if (name[0] == 'n' && name[1] == 'o' && name[2]) {
+			for (p = desc; p->name; p++) {
+				if (strcmp(p->name, name + 2) != 0)
+					continue;
+				if (!(p->flags & fs_param_neg_with_no))
+					continue;
+				*negated = true;
+				return p;
+			}
+		}
+	}
+	return other;
+}
+
+/*
+ * __fs_parse - Parse a filesystem configuration parameter
+ * @log: The filesystem context to log errors through.
+ * @desc: The parameter description to use.
+ * @param: The parameter.
+ * @result: Where to place the result of the parse
+ *
+ * Parse a filesystem configuration parameter and attempt a conversion for a
+ * simple parameter for which this is requested.  If successful, the determined
+ * parameter ID is placed into @result->key, the desired type is indicated in
+ * @result->t and any converted value is placed into an appropriate member of
+ * the union in @result.
+ *
+ * The function returns the parameter number if the parameter was matched,
+ * -ENOPARAM if it wasn't matched and @desc->ignore_unknown indicated that
+ * unknown parameters are okay and -EINVAL if there was a conversion issue or
+ * the parameter wasn't recognised and unknowns aren't okay.
+ */
+int __fs_parse(struct p_log *log,
+	     const struct fs_parameter_spec *desc,
+	     struct fs_parameter *param,
+	     struct fs_parse_result *result)
+{
+	const struct fs_parameter_spec *p;
+
+	result->uint_64 = 0;
+
+	p = fs_lookup_key(desc, param, &result->negated);
+	if (!p)
+		return -ENOPARAM;
+
+	if (p->flags & fs_param_deprecated)
+		warn_plog(log, "Deprecated parameter '%s'", param->key);
+
+	/* Try to turn the type we were given into the type desired by the
+	 * parameter and give an error if we can't.
+	 */
+	if (is_flag(p)) {
+		if (param->type != fs_value_is_flag)
+			return inval_plog(log, "Unexpected value for '%s'",
+				      param->key);
+		result->boolean = !result->negated;
+	} else  {
+		int ret = p->type(log, p, param, result);
+		if (ret)
+			return ret;
+	}
+	return p->opt;
+}
+EXPORT_SYMBOL(__fs_parse);
+
+/**
+ * fs_lookup_param - Look up a path referred to by a parameter
+ * @fc: The filesystem context to log errors through.
+ * @param: The parameter.
+ * @want_bdev: T if want a blockdev
+ * @flags: Pathwalk flags passed to filename_lookup()
+ * @_path: The result of the lookup
+ */
+int fs_lookup_param(struct fs_context *fc,
+		    struct fs_parameter *param,
+		    bool want_bdev,
+		    unsigned int flags,
+		    struct path *_path)
+{
+	struct filename *f;
+	bool put_f;
+	int ret;
+
+	switch (param->type) {
+	case fs_value_is_string:
+		f = getname_kernel(param->string);
+		if (IS_ERR(f))
+			return PTR_ERR(f);
+		param->dirfd = AT_FDCWD;
+		put_f = true;
+		break;
+	case fs_value_is_filename:
+		f = param->name;
+		put_f = false;
+		break;
+	default:
+		return invalf(fc, "%s: not usable as path", param->key);
+	}
+
+	ret = filename_lookup(param->dirfd, f, flags, _path, NULL);
+	if (ret < 0) {
+		errorf(fc, "%s: Lookup failure for '%s'", param->key, f->name);
+		goto out;
+	}
+
+	if (want_bdev &&
+	    !S_ISBLK(d_backing_inode(_path->dentry)->i_mode)) {
+		path_put(_path);
+		_path->dentry = NULL;
+		_path->mnt = NULL;
+		errorf(fc, "%s: Non-blockdev passed as '%s'",
+		       param->key, f->name);
+		ret = -ENOTBLK;
+	}
+
+out:
+	if (put_f)
+		putname(f);
+	return ret;
+}
+EXPORT_SYMBOL(fs_lookup_param);
+
+static int fs_param_bad_value(struct p_log *log, struct fs_parameter *param)
+{
+	return inval_plog(log, "Bad value for '%s'", param->key);
+}
+
+int fs_param_is_bool(struct p_log *log, const struct fs_parameter_spec *p,
+		     struct fs_parameter *param, struct fs_parse_result *result)
+{
+	int b;
+	if (param->type != fs_value_is_string)
+		return fs_param_bad_value(log, param);
+	if (!*param->string && (p->flags & fs_param_can_be_empty))
+		return 0;
+	b = lookup_constant(bool_names, param->string, -1);
+	if (b == -1)
+		return fs_param_bad_value(log, param);
+	result->boolean = b;
+	return 0;
+}
+EXPORT_SYMBOL(fs_param_is_bool);
+
+int fs_param_is_u32(struct p_log *log, const struct fs_parameter_spec *p,
+		    struct fs_parameter *param, struct fs_parse_result *result)
+{
+	int base = (unsigned long)p->data;
+	if (param->type != fs_value_is_string)
+		return fs_param_bad_value(log, param);
+	if (!*param->string && (p->flags & fs_param_can_be_empty))
+		return 0;
+	if (kstrtouint(param->string, base, &result->uint_32) < 0)
+		return fs_param_bad_value(log, param);
+	return 0;
+}
+EXPORT_SYMBOL(fs_param_is_u32);
+
+int fs_param_is_s32(struct p_log *log, const struct fs_parameter_spec *p,
+		    struct fs_parameter *param, struct fs_parse_result *result)
+{
+	if (param->type != fs_value_is_string)
+		return fs_param_bad_value(log, param);
+	if (!*param->string && (p->flags & fs_param_can_be_empty))
+		return 0;
+	if (kstrtoint(param->string, 0, &result->int_32) < 0)
+		return fs_param_bad_value(log, param);
+	return 0;
+}
+EXPORT_SYMBOL(fs_param_is_s32);
+
+int fs_param_is_u64(struct p_log *log, const struct fs_parameter_spec *p,
+		    struct fs_parameter *param, struct fs_parse_result *result)
+{
+	if (param->type != fs_value_is_string)
+		return fs_param_bad_value(log, param);
+	if (!*param->string && (p->flags & fs_param_can_be_empty))
+		return 0;
+	if (kstrtoull(param->string, 0, &result->uint_64) < 0)
+		return fs_param_bad_value(log, param);
+	return 0;
+}
+EXPORT_SYMBOL(fs_param_is_u64);
+
+int fs_param_is_enum(struct p_log *log, const struct fs_parameter_spec *p,
+		     struct fs_parameter *param, struct fs_parse_result *result)
+{
+	const struct constant_table *c;
+	if (param->type != fs_value_is_string)
+		return fs_param_bad_value(log, param);
+	if (!*param->string && (p->flags & fs_param_can_be_empty))
+		return 0;
+	c = __lookup_constant(p->data, param->string);
+	if (!c)
+		return fs_param_bad_value(log, param);
+	result->uint_32 = c->value;
+	return 0;
+}
+EXPORT_SYMBOL(fs_param_is_enum);
+
+int fs_param_is_string(struct p_log *log, const struct fs_parameter_spec *p,
+		       struct fs_parameter *param, struct fs_parse_result *result)
+{
+	if (param->type != fs_value_is_string ||
+	    (!*param->string && !(p->flags & fs_param_can_be_empty)))
+		return fs_param_bad_value(log, param);
+	return 0;
+}
+EXPORT_SYMBOL(fs_param_is_string);
+
+int fs_param_is_fd(struct p_log *log, const struct fs_parameter_spec *p,
+		  struct fs_parameter *param, struct fs_parse_result *result)
+{
+	switch (param->type) {
+	case fs_value_is_string:
+		if ((!*param->string && !(p->flags & fs_param_can_be_empty)) ||
+		    kstrtouint(param->string, 0, &result->uint_32) < 0)
+			break;
+		if (result->uint_32 <= INT_MAX)
+			return 0;
+		break;
+	case fs_value_is_file:
+		result->uint_32 = param->dirfd;
+		if (result->uint_32 <= INT_MAX)
+			return 0;
+		break;
+	default:
+		break;
+	}
+	return fs_param_bad_value(log, param);
+}
+EXPORT_SYMBOL(fs_param_is_fd);
+
+int fs_param_is_file_or_string(struct p_log *log,
+			       const struct fs_parameter_spec *p,
+			       struct fs_parameter *param,
+			       struct fs_parse_result *result)
+{
+	switch (param->type) {
+	case fs_value_is_string:
+		return fs_param_is_string(log, p, param, result);
+	case fs_value_is_file:
+		result->uint_32 = param->dirfd;
+		if (result->uint_32 <= INT_MAX)
+			return 0;
+		break;
+	default:
+		break;
+	}
+	return fs_param_bad_value(log, param);
+}
+EXPORT_SYMBOL(fs_param_is_file_or_string);
+
+int fs_param_is_uid(struct p_log *log, const struct fs_parameter_spec *p,
+		    struct fs_parameter *param, struct fs_parse_result *result)
+{
+	kuid_t uid;
+
+	if (fs_param_is_u32(log, p, param, result) != 0)
+		return fs_param_bad_value(log, param);
+
+	uid = make_kuid(current_user_ns(), result->uint_32);
+	if (!uid_valid(uid))
+		return inval_plog(log, "Invalid uid '%s'", param->string);
+
+	result->uid = uid;
+	return 0;
+}
+EXPORT_SYMBOL(fs_param_is_uid);
+
+int fs_param_is_gid(struct p_log *log, const struct fs_parameter_spec *p,
+		    struct fs_parameter *param, struct fs_parse_result *result)
+{
+	kgid_t gid;
+
+	if (fs_param_is_u32(log, p, param, result) != 0)
+		return fs_param_bad_value(log, param);
+
+	gid = make_kgid(current_user_ns(), result->uint_32);
+	if (!gid_valid(gid))
+		return inval_plog(log, "Invalid gid '%s'", param->string);
+
+	result->gid = gid;
+	return 0;
+}
+EXPORT_SYMBOL(fs_param_is_gid);
+
+int fs_param_is_blockdev(struct p_log *log, const struct fs_parameter_spec *p,
+		  struct fs_parameter *param, struct fs_parse_result *result)
+{
+	return 0;
+}
+EXPORT_SYMBOL(fs_param_is_blockdev);
+
+#ifdef CONFIG_VALIDATE_FS_PARSER
+/**
+ * fs_validate_description - Validate a parameter specification array
+ * @name: Owner name of the parameter specification array
+ * @desc: The parameter specification array to validate.
+ */
+bool fs_validate_description(const char *name,
+	const struct fs_parameter_spec *desc)
+{
+	const struct fs_parameter_spec *param, *p2;
+	bool good = true;
+
+	for (param = desc; param->name; param++) {
+		/* Check for duplicate parameter names */
+		for (p2 = desc; p2 < param; p2++) {
+			if (strcmp(param->name, p2->name) == 0) {
+				if (is_flag(param) != is_flag(p2))
+					continue;
+				pr_err("VALIDATE %s: PARAM[%s]: Duplicate\n",
+				       name, param->name);
+				good = false;
+			}
+		}
+	}
+	return good;
+}
+#endif /* CONFIG_VALIDATE_FS_PARSER */