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, 581 insertions, 0 deletions

diff --git a/scripts/kconfig/preprocess.c b/scripts/kconfig/preprocess.c
new file mode 100644
index 000000000..783abcaa5
--- /dev/null
+++ b/scripts/kconfig/preprocess.c
@@ -0,0 +1,581 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (C) 2018 Masahiro Yamada <yamada.masahiro@socionext.com>
+
+#include <ctype.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <array_size.h>
+#include <list.h>
+#include <xalloc.h>
+#include "internal.h"
+#include "lkc.h"
+#include "preprocess.h"
+
+static char *expand_string_with_args(const char *in, int argc, char *argv[]);
+static char *expand_string(const char *in);
+
+static void __attribute__((noreturn)) pperror(const char *format, ...)
+{
+	va_list ap;
+
+	fprintf(stderr, "%s:%d: ", cur_filename, yylineno);
+	va_start(ap, format);
+	vfprintf(stderr, format, ap);
+	va_end(ap);
+	fprintf(stderr, "\n");
+
+	exit(1);
+}
+
+/*
+ * Environment variables
+ */
+static LIST_HEAD(env_list);
+
+struct env {
+	char *name;
+	char *value;
+	struct list_head node;
+};
+
+static void env_add(const char *name, const char *value)
+{
+	struct env *e;
+
+	e = xmalloc(sizeof(*e));
+	e->name = xstrdup(name);
+	e->value = xstrdup(value);
+
+	list_add_tail(&e->node, &env_list);
+}
+
+static void env_del(struct env *e)
+{
+	list_del(&e->node);
+	free(e->name);
+	free(e->value);
+	free(e);
+}
+
+/* The returned pointer must be freed when done */
+static char *env_expand(const char *name)
+{
+	struct env *e;
+	const char *value;
+
+	if (!*name)
+		return NULL;
+
+	list_for_each_entry(e, &env_list, node) {
+		if (!strcmp(name, e->name))
+			return xstrdup(e->value);
+	}
+
+	value = getenv(name);
+	if (!value)
+		return NULL;
+
+	/*
+	 * We need to remember all referenced environment variables.
+	 * They will be written out to include/config/auto.conf.cmd
+	 */
+	env_add(name, value);
+
+	return xstrdup(value);
+}
+
+void env_write_dep(struct gstr *s)
+{
+	struct env *e, *tmp;
+
+	list_for_each_entry_safe(e, tmp, &env_list, node) {
+		str_printf(s,
+			   "\n"
+			   "ifneq \"$(%s)\" \"%s\"\n"
+			   "$(autoconfig): FORCE\n"
+			   "endif\n",
+			   e->name, e->value);
+		env_del(e);
+	}
+}
+
+/*
+ * Built-in functions
+ */
+struct function {
+	const char *name;
+	unsigned int min_args;
+	unsigned int max_args;
+	char *(*func)(int argc, char *argv[]);
+};
+
+static char *do_error_if(int argc, char *argv[])
+{
+	if (!strcmp(argv[0], "y"))
+		pperror("%s", argv[1]);
+
+	return xstrdup("");
+}
+
+static char *do_filename(int argc, char *argv[])
+{
+	return xstrdup(cur_filename);
+}
+
+static char *do_info(int argc, char *argv[])
+{
+	printf("%s\n", argv[0]);
+
+	return xstrdup("");
+}
+
+static char *do_lineno(int argc, char *argv[])
+{
+	char buf[16];
+
+	sprintf(buf, "%d", yylineno);
+
+	return xstrdup(buf);
+}
+
+static char *do_shell(int argc, char *argv[])
+{
+	FILE *p;
+	char buf[4096];
+	char *cmd;
+	size_t nread;
+	int i;
+
+	cmd = argv[0];
+
+	p = popen(cmd, "r");
+	if (!p) {
+		perror(cmd);
+		exit(1);
+	}
+
+	nread = fread(buf, 1, sizeof(buf), p);
+	if (nread == sizeof(buf))
+		nread--;
+
+	/* remove trailing new lines */
+	while (nread > 0 && buf[nread - 1] == '\n')
+		nread--;
+
+	buf[nread] = 0;
+
+	/* replace a new line with a space */
+	for (i = 0; i < nread; i++) {
+		if (buf[i] == '\n')
+			buf[i] = ' ';
+	}
+
+	if (pclose(p) == -1) {
+		perror(cmd);
+		exit(1);
+	}
+
+	return xstrdup(buf);
+}
+
+static char *do_warning_if(int argc, char *argv[])
+{
+	if (!strcmp(argv[0], "y"))
+		fprintf(stderr, "%s:%d: %s\n", cur_filename, yylineno, argv[1]);
+
+	return xstrdup("");
+}
+
+static const struct function function_table[] = {
+	/* Name		MIN	MAX	Function */
+	{ "error-if",	2,	2,	do_error_if },
+	{ "filename",	0,	0,	do_filename },
+	{ "info",	1,	1,	do_info },
+	{ "lineno",	0,	0,	do_lineno },
+	{ "shell",	1,	1,	do_shell },
+	{ "warning-if",	2,	2,	do_warning_if },
+};
+
+#define FUNCTION_MAX_ARGS		16
+
+static char *function_expand(const char *name, int argc, char *argv[])
+{
+	const struct function *f;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(function_table); i++) {
+		f = &function_table[i];
+		if (strcmp(f->name, name))
+			continue;
+
+		if (argc < f->min_args)
+			pperror("too few function arguments passed to '%s'",
+				name);
+
+		if (argc > f->max_args)
+			pperror("too many function arguments passed to '%s'",
+				name);
+
+		return f->func(argc, argv);
+	}
+
+	return NULL;
+}
+
+/*
+ * Variables (and user-defined functions)
+ */
+static LIST_HEAD(variable_list);
+
+struct variable {
+	char *name;
+	char *value;
+	enum variable_flavor flavor;
+	int exp_count;
+	struct list_head node;
+};
+
+static struct variable *variable_lookup(const char *name)
+{
+	struct variable *v;
+
+	list_for_each_entry(v, &variable_list, node) {
+		if (!strcmp(name, v->name))
+			return v;
+	}
+
+	return NULL;
+}
+
+static char *variable_expand(const char *name, int argc, char *argv[])
+{
+	struct variable *v;
+	char *res;
+
+	v = variable_lookup(name);
+	if (!v)
+		return NULL;
+
+	if (argc == 0 && v->exp_count)
+		pperror("Recursive variable '%s' references itself (eventually)",
+			name);
+
+	if (v->exp_count > 1000)
+		pperror("Too deep recursive expansion");
+
+	v->exp_count++;
+
+	if (v->flavor == VAR_RECURSIVE)
+		res = expand_string_with_args(v->value, argc, argv);
+	else
+		res = xstrdup(v->value);
+
+	v->exp_count--;
+
+	return res;
+}
+
+void variable_add(const char *name, const char *value,
+		  enum variable_flavor flavor)
+{
+	struct variable *v;
+	char *new_value;
+	bool append = false;
+
+	v = variable_lookup(name);
+	if (v) {
+		/* For defined variables, += inherits the existing flavor */
+		if (flavor == VAR_APPEND) {
+			flavor = v->flavor;
+			append = true;
+		} else {
+			free(v->value);
+		}
+	} else {
+		/* For undefined variables, += assumes the recursive flavor */
+		if (flavor == VAR_APPEND)
+			flavor = VAR_RECURSIVE;
+
+		v = xmalloc(sizeof(*v));
+		v->name = xstrdup(name);
+		v->exp_count = 0;
+		list_add_tail(&v->node, &variable_list);
+	}
+
+	v->flavor = flavor;
+
+	if (flavor == VAR_SIMPLE)
+		new_value = expand_string(value);
+	else
+		new_value = xstrdup(value);
+
+	if (append) {
+		v->value = xrealloc(v->value,
+				    strlen(v->value) + strlen(new_value) + 2);
+		strcat(v->value, " ");
+		strcat(v->value, new_value);
+		free(new_value);
+	} else {
+		v->value = new_value;
+	}
+}
+
+static void variable_del(struct variable *v)
+{
+	list_del(&v->node);
+	free(v->name);
+	free(v->value);
+	free(v);
+}
+
+void variable_all_del(void)
+{
+	struct variable *v, *tmp;
+
+	list_for_each_entry_safe(v, tmp, &variable_list, node)
+		variable_del(v);
+}
+
+/*
+ * Evaluate a clause with arguments.  argc/argv are arguments from the upper
+ * function call.
+ *
+ * Returned string must be freed when done
+ */
+static char *eval_clause(const char *str, size_t len, int argc, char *argv[])
+{
+	char *tmp, *name, *res, *endptr, *prev, *p;
+	int new_argc = 0;
+	char *new_argv[FUNCTION_MAX_ARGS];
+	int nest = 0;
+	int i;
+	unsigned long n;
+
+	tmp = xstrndup(str, len);
+
+	/*
+	 * If variable name is '1', '2', etc.  It is generally an argument
+	 * from a user-function call (i.e. local-scope variable).  If not
+	 * available, then look-up global-scope variables.
+	 */
+	n = strtoul(tmp, &endptr, 10);
+	if (!*endptr && n > 0 && n <= argc) {
+		res = xstrdup(argv[n - 1]);
+		goto free_tmp;
+	}
+
+	prev = p = tmp;
+
+	/*
+	 * Split into tokens
+	 * The function name and arguments are separated by a comma.
+	 * For example, if the function call is like this:
+	 *   $(foo,$(x),$(y))
+	 *
+	 * The input string for this helper should be:
+	 *   foo,$(x),$(y)
+	 *
+	 * and split into:
+	 *   new_argv[0] = 'foo'
+	 *   new_argv[1] = '$(x)'
+	 *   new_argv[2] = '$(y)'
+	 */
+	while (*p) {
+		if (nest == 0 && *p == ',') {
+			*p = 0;
+			if (new_argc >= FUNCTION_MAX_ARGS)
+				pperror("too many function arguments");
+			new_argv[new_argc++] = prev;
+			prev = p + 1;
+		} else if (*p == '(') {
+			nest++;
+		} else if (*p == ')') {
+			nest--;
+		}
+
+		p++;
+	}
+
+	if (new_argc >= FUNCTION_MAX_ARGS)
+		pperror("too many function arguments");
+	new_argv[new_argc++] = prev;
+
+	/*
+	 * Shift arguments
+	 * new_argv[0] represents a function name or a variable name.  Put it
+	 * into 'name', then shift the rest of the arguments.  This simplifies
+	 * 'const' handling.
+	 */
+	name = expand_string_with_args(new_argv[0], argc, argv);
+	new_argc--;
+	for (i = 0; i < new_argc; i++)
+		new_argv[i] = expand_string_with_args(new_argv[i + 1],
+						      argc, argv);
+
+	/* Search for variables */
+	res = variable_expand(name, new_argc, new_argv);
+	if (res)
+		goto free;
+
+	/* Look for built-in functions */
+	res = function_expand(name, new_argc, new_argv);
+	if (res)
+		goto free;
+
+	/* Last, try environment variable */
+	if (new_argc == 0) {
+		res = env_expand(name);
+		if (res)
+			goto free;
+	}
+
+	res = xstrdup("");
+free:
+	for (i = 0; i < new_argc; i++)
+		free(new_argv[i]);
+	free(name);
+free_tmp:
+	free(tmp);
+
+	return res;
+}
+
+/*
+ * Expand a string that follows '$'
+ *
+ * For example, if the input string is
+ *     ($(FOO)$($(BAR)))$(BAZ)
+ * this helper evaluates
+ *     $($(FOO)$($(BAR)))
+ * and returns a new string containing the expansion (note that the string is
+ * recursively expanded), also advancing 'str' to point to the next character
+ * after the corresponding closing parenthesis, in this case, *str will be
+ *     $(BAR)
+ */
+static char *expand_dollar_with_args(const char **str, int argc, char *argv[])
+{
+	const char *p = *str;
+	const char *q;
+	int nest = 0;
+
+	/*
+	 * In Kconfig, variable/function references always start with "$(".
+	 * Neither single-letter variables as in $A nor curly braces as in ${CC}
+	 * are supported.  '$' not followed by '(' loses its special meaning.
+	 */
+	if (*p != '(') {
+		*str = p;
+		return xstrdup("$");
+	}
+
+	p++;
+	q = p;
+	while (*q) {
+		if (*q == '(') {
+			nest++;
+		} else if (*q == ')') {
+			if (nest-- == 0)
+				break;
+		}
+		q++;
+	}
+
+	if (!*q)
+		pperror("unterminated reference to '%s': missing ')'", p);
+
+	/* Advance 'str' to after the expanded initial portion of the string */
+	*str = q + 1;
+
+	return eval_clause(p, q - p, argc, argv);
+}
+
+char *expand_dollar(const char **str)
+{
+	return expand_dollar_with_args(str, 0, NULL);
+}
+
+static char *__expand_string(const char **str, bool (*is_end)(char c),
+			     int argc, char *argv[])
+{
+	const char *in, *p;
+	char *expansion, *out;
+	size_t in_len, out_len;
+
+	out = xmalloc(1);
+	*out = 0;
+	out_len = 1;
+
+	p = in = *str;
+
+	while (1) {
+		if (*p == '$') {
+			in_len = p - in;
+			p++;
+			expansion = expand_dollar_with_args(&p, argc, argv);
+			out_len += in_len + strlen(expansion);
+			out = xrealloc(out, out_len);
+			strncat(out, in, in_len);
+			strcat(out, expansion);
+			free(expansion);
+			in = p;
+			continue;
+		}
+
+		if (is_end(*p))
+			break;
+
+		p++;
+	}
+
+	in_len = p - in;
+	out_len += in_len;
+	out = xrealloc(out, out_len);
+	strncat(out, in, in_len);
+
+	/* Advance 'str' to the end character */
+	*str = p;
+
+	return out;
+}
+
+static bool is_end_of_str(char c)
+{
+	return !c;
+}
+
+/*
+ * Expand variables and functions in the given string.  Undefined variables
+ * expand to an empty string.
+ * The returned string must be freed when done.
+ */
+static char *expand_string_with_args(const char *in, int argc, char *argv[])
+{
+	return __expand_string(&in, is_end_of_str, argc, argv);
+}
+
+static char *expand_string(const char *in)
+{
+	return expand_string_with_args(in, 0, NULL);
+}
+
+static bool is_end_of_token(char c)
+{
+	return !(isalnum(c) || c == '_' || c == '-');
+}
+
+/*
+ * Expand variables in a token.  The parsing stops when a token separater
+ * (in most cases, it is a whitespace) is encountered.  'str' is updated to
+ * point to the next character.
+ *
+ * The returned string must be freed when done.
+ */
+char *expand_one_token(const char **str)
+{
+	return __expand_string(str, is_end_of_token, 0, NULL);
+}