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, 884 insertions, 0 deletions

diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
new file mode 100644
index 000000000..9c079e92a
--- /dev/null
+++ b/scripts/kconfig/menu.c
@@ -0,0 +1,884 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
+ */
+
+#include <ctype.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <list.h>
+#include <xalloc.h>
+#include "lkc.h"
+#include "internal.h"
+
+static const char nohelp_text[] = "There is no help available for this option.";
+
+struct menu rootmenu = { .type = M_MENU };
+static struct menu **last_entry_ptr;
+
+/**
+ * menu_next - return the next menu entry with depth-first traversal
+ * @menu: pointer to the current menu
+ * @root: root of the sub-tree to traverse. If NULL is given, the traveral
+ *        continues until it reaches the end of the entire menu tree.
+ * return: the menu to visit next, or NULL when it reaches the end.
+ */
+struct menu *menu_next(struct menu *menu, struct menu *root)
+{
+	if (menu->list)
+		return menu->list;
+
+	while (menu != root && !menu->next)
+		menu = menu->parent;
+
+	if (menu == root)
+		return NULL;
+
+	return menu->next;
+}
+
+void menu_warn(const struct menu *menu, const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	fprintf(stderr, "%s:%d:warning: ", menu->filename, menu->lineno);
+	vfprintf(stderr, fmt, ap);
+	fprintf(stderr, "\n");
+	va_end(ap);
+}
+
+static void prop_warn(const struct property *prop, const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	fprintf(stderr, "%s:%d:warning: ", prop->filename, prop->lineno);
+	vfprintf(stderr, fmt, ap);
+	fprintf(stderr, "\n");
+	va_end(ap);
+}
+
+void _menu_init(void)
+{
+	current_entry = current_menu = &rootmenu;
+	last_entry_ptr = &rootmenu.list;
+}
+
+void menu_add_entry(struct symbol *sym, enum menu_type type)
+{
+	struct menu *menu;
+
+	menu = xmalloc(sizeof(*menu));
+	memset(menu, 0, sizeof(*menu));
+	menu->type = type;
+	menu->sym = sym;
+	menu->parent = current_menu;
+	menu->filename = cur_filename;
+	menu->lineno = cur_lineno;
+
+	*last_entry_ptr = menu;
+	last_entry_ptr = &menu->next;
+	current_entry = menu;
+	if (sym)
+		list_add_tail(&menu->link, &sym->menus);
+}
+
+struct menu *menu_add_menu(void)
+{
+	last_entry_ptr = &current_entry->list;
+	current_menu = current_entry;
+	return current_menu;
+}
+
+void menu_end_menu(void)
+{
+	last_entry_ptr = &current_menu->next;
+	current_menu = current_menu->parent;
+}
+
+/*
+ * Rewrites 'm' to 'm' && MODULES, so that it evaluates to 'n' when running
+ * without modules
+ */
+static struct expr *rewrite_m(struct expr *e)
+{
+	if (!e)
+		return e;
+
+	switch (e->type) {
+	case E_NOT:
+		e = expr_alloc_one(E_NOT, rewrite_m(e->left.expr));
+		break;
+	case E_OR:
+	case E_AND:
+		e = expr_alloc_two(e->type,
+				   rewrite_m(e->left.expr),
+				   rewrite_m(e->right.expr));
+		break;
+	case E_SYMBOL:
+		/* change 'm' into 'm' && MODULES */
+		if (e->left.sym == &symbol_mod)
+			return expr_alloc_and(e, expr_alloc_symbol(modules_sym));
+		break;
+	default:
+		break;
+	}
+	return e;
+}
+
+void menu_add_dep(struct expr *dep, struct expr *cond)
+{
+	if (cond) {
+		/*
+		 * We have "depends on X if Y" and we want:
+		 *	Y != n --> X
+		 *	Y == n --> y
+		 * That simplifies to: (X || (Y == n))
+		 */
+		dep = expr_alloc_or(dep,
+				expr_trans_compare(cond, E_EQUAL, &symbol_no));
+	}
+	current_entry->dep = expr_alloc_and(current_entry->dep, dep);
+}
+
+void menu_set_type(int type)
+{
+	struct symbol *sym = current_entry->sym;
+
+	if (sym->type == type)
+		return;
+	if (sym->type == S_UNKNOWN) {
+		sym->type = type;
+		return;
+	}
+	menu_warn(current_entry,
+		"ignoring type redefinition of '%s' from '%s' to '%s'",
+		sym->name ? sym->name : "<choice>",
+		sym_type_name(sym->type), sym_type_name(type));
+}
+
+static struct property *menu_add_prop(enum prop_type type, struct expr *expr,
+				      struct expr *dep)
+{
+	struct property *prop;
+
+	prop = xmalloc(sizeof(*prop));
+	memset(prop, 0, sizeof(*prop));
+	prop->type = type;
+	prop->filename = cur_filename;
+	prop->lineno = cur_lineno;
+	prop->menu = current_entry;
+	prop->expr = expr;
+	prop->visible.expr = dep;
+
+	/* append property to the prop list of symbol */
+	if (current_entry->sym) {
+		struct property **propp;
+
+		for (propp = &current_entry->sym->prop;
+		     *propp;
+		     propp = &(*propp)->next)
+			;
+		*propp = prop;
+	}
+
+	return prop;
+}
+
+struct property *menu_add_prompt(enum prop_type type, const char *prompt,
+				 struct expr *dep)
+{
+	struct property *prop = menu_add_prop(type, NULL, dep);
+
+	if (isspace(*prompt)) {
+		prop_warn(prop, "leading whitespace ignored");
+		while (isspace(*prompt))
+			prompt++;
+	}
+	if (current_entry->prompt)
+		prop_warn(prop, "prompt redefined");
+
+	/* Apply all upper menus' visibilities to actual prompts. */
+	if (type == P_PROMPT) {
+		struct menu *menu = current_entry;
+
+		while ((menu = menu->parent) != NULL) {
+
+			if (!menu->visibility)
+				continue;
+			prop->visible.expr = expr_alloc_and(prop->visible.expr,
+							    menu->visibility);
+		}
+	}
+
+	current_entry->prompt = prop;
+	prop->text = prompt;
+
+	return prop;
+}
+
+void menu_add_visibility(struct expr *expr)
+{
+	current_entry->visibility = expr_alloc_and(current_entry->visibility,
+	    expr);
+}
+
+void menu_add_expr(enum prop_type type, struct expr *expr, struct expr *dep)
+{
+	menu_add_prop(type, expr, dep);
+}
+
+void menu_add_symbol(enum prop_type type, struct symbol *sym, struct expr *dep)
+{
+	menu_add_prop(type, expr_alloc_symbol(sym), dep);
+}
+
+static int menu_validate_number(struct symbol *sym, struct symbol *sym2)
+{
+	return sym2->type == S_INT || sym2->type == S_HEX ||
+	       (sym2->type == S_UNKNOWN && sym_string_valid(sym, sym2->name));
+}
+
+static void sym_check_prop(struct symbol *sym)
+{
+	struct property *prop;
+	struct symbol *sym2;
+	char *use;
+
+	for (prop = sym->prop; prop; prop = prop->next) {
+		switch (prop->type) {
+		case P_DEFAULT:
+			if ((sym->type == S_STRING || sym->type == S_INT || sym->type == S_HEX) &&
+			    prop->expr->type != E_SYMBOL)
+				prop_warn(prop,
+				    "default for config symbol '%s'"
+				    " must be a single symbol", sym->name);
+			if (prop->expr->type != E_SYMBOL)
+				break;
+			sym2 = prop_get_symbol(prop);
+			if (sym->type == S_HEX || sym->type == S_INT) {
+				if (!menu_validate_number(sym, sym2))
+					prop_warn(prop,
+					    "'%s': number is invalid",
+					    sym->name);
+			}
+			if (sym_is_choice(sym)) {
+				struct menu *choice = sym_get_choice_menu(sym2);
+
+				if (!choice || choice->sym != sym)
+					prop_warn(prop,
+						  "choice default symbol '%s' is not contained in the choice",
+						  sym2->name);
+			}
+			break;
+		case P_SELECT:
+		case P_IMPLY:
+			use = prop->type == P_SELECT ? "select" : "imply";
+			sym2 = prop_get_symbol(prop);
+			if (sym->type != S_BOOLEAN && sym->type != S_TRISTATE)
+				prop_warn(prop,
+				    "config symbol '%s' uses %s, but is "
+				    "not bool or tristate", sym->name, use);
+			else if (sym2->type != S_UNKNOWN &&
+				 sym2->type != S_BOOLEAN &&
+				 sym2->type != S_TRISTATE)
+				prop_warn(prop,
+				    "'%s' has wrong type. '%s' only "
+				    "accept arguments of bool and "
+				    "tristate type", sym2->name, use);
+			break;
+		case P_RANGE:
+			if (sym->type != S_INT && sym->type != S_HEX)
+				prop_warn(prop, "range is only allowed "
+						"for int or hex symbols");
+			if (!menu_validate_number(sym, prop->expr->left.sym) ||
+			    !menu_validate_number(sym, prop->expr->right.sym))
+				prop_warn(prop, "range is invalid");
+			break;
+		default:
+			;
+		}
+	}
+}
+
+static void _menu_finalize(struct menu *parent, bool inside_choice)
+{
+	struct menu *menu, *last_menu;
+	struct symbol *sym;
+	struct property *prop;
+	struct expr *basedep, *dep, *dep2;
+
+	sym = parent->sym;
+	if (parent->list) {
+		/*
+		 * This menu node has children. We (recursively) process them
+		 * and propagate parent dependencies before moving on.
+		 */
+
+		/* For each child menu node... */
+		for (menu = parent->list; menu; menu = menu->next) {
+			/*
+			 * Propagate parent dependencies to the child menu
+			 * node, also rewriting and simplifying expressions
+			 */
+			basedep = rewrite_m(menu->dep);
+			basedep = expr_transform(basedep);
+			basedep = expr_alloc_and(parent->dep, basedep);
+			basedep = expr_eliminate_dups(basedep);
+			menu->dep = basedep;
+
+			if (menu->sym)
+				/*
+				 * Note: For symbols, all prompts are included
+				 * too in the symbol's own property list
+				 */
+				prop = menu->sym->prop;
+			else
+				/*
+				 * For non-symbol menu nodes, we just need to
+				 * handle the prompt
+				 */
+				prop = menu->prompt;
+
+			/* For each property... */
+			for (; prop; prop = prop->next) {
+				if (prop->menu != menu)
+					/*
+					 * Two possibilities:
+					 *
+					 * 1. The property lacks dependencies
+					 *    and so isn't location-specific,
+					 *    e.g. an 'option'
+					 *
+					 * 2. The property belongs to a symbol
+					 *    defined in multiple locations and
+					 *    is from some other location. It
+					 *    will be handled there in that
+					 *    case.
+					 *
+					 * Skip the property.
+					 */
+					continue;
+
+				/*
+				 * Propagate parent dependencies to the
+				 * property's condition, rewriting and
+				 * simplifying expressions at the same time
+				 */
+				dep = rewrite_m(prop->visible.expr);
+				dep = expr_transform(dep);
+				dep = expr_alloc_and(basedep, dep);
+				dep = expr_eliminate_dups(dep);
+				prop->visible.expr = dep;
+
+				/*
+				 * Handle selects and implies, which modify the
+				 * dependencies of the selected/implied symbol
+				 */
+				if (prop->type == P_SELECT) {
+					struct symbol *es = prop_get_symbol(prop);
+					es->rev_dep.expr = expr_alloc_or(es->rev_dep.expr,
+							expr_alloc_and(expr_alloc_symbol(menu->sym), dep));
+				} else if (prop->type == P_IMPLY) {
+					struct symbol *es = prop_get_symbol(prop);
+					es->implied.expr = expr_alloc_or(es->implied.expr,
+							expr_alloc_and(expr_alloc_symbol(menu->sym), dep));
+				}
+			}
+		}
+
+		/*
+		 * Recursively process children in the same fashion before
+		 * moving on
+		 */
+		for (menu = parent->list; menu; menu = menu->next)
+			_menu_finalize(menu, sym && sym_is_choice(sym));
+	} else if (!inside_choice && sym) {
+		/*
+		 * Automatic submenu creation. If sym is a symbol and A, B, C,
+		 * ... are consecutive items (symbols, menus, ifs, etc.) that
+		 * all depend on sym, then the following menu structure is
+		 * created:
+		 *
+		 *	sym
+		 *	 +-A
+		 *	 +-B
+		 *	 +-C
+		 *	 ...
+		 *
+		 * This also works recursively, giving the following structure
+		 * if A is a symbol and B depends on A:
+		 *
+		 *	sym
+		 *	 +-A
+		 *	 | +-B
+		 *	 +-C
+		 *	 ...
+		 */
+
+		basedep = parent->prompt ? parent->prompt->visible.expr : NULL;
+		basedep = expr_trans_compare(basedep, E_UNEQUAL, &symbol_no);
+		basedep = expr_eliminate_dups(expr_transform(basedep));
+
+		/* Examine consecutive elements after sym */
+		last_menu = NULL;
+		for (menu = parent->next; menu; menu = menu->next) {
+			dep = menu->prompt ? menu->prompt->visible.expr : menu->dep;
+			if (!expr_contains_symbol(dep, sym))
+				/* No dependency, quit */
+				break;
+			/*
+			 * Note that it's actually possible to depend on both
+			 * 'SYM!=y' and 'SYM=y', so we need to first check if
+			 * it's a positive dependency before checking if it's
+			 * a negative dependency. See example:
+			 * 'SFC && MTD && !(SFC=y && MTD=m)'
+			 */
+			if (expr_depends_symbol(dep, sym))
+				/* Absolute dependency, put in submenu */
+				goto next;
+			if (expr_contains_symbol_negated(dep, sym))
+				/* Negative dependency, quit */
+				break;
+
+			/*
+			 * Also consider it a dependency on sym if our
+			 * dependencies contain sym and are a "superset" of
+			 * sym's dependencies, e.g. '(sym || Q) && R' when sym
+			 * depends on R.
+			 *
+			 * Note that 'R' might be from an enclosing menu or if,
+			 * making this a more common case than it might seem.
+			 */
+			dep = expr_trans_compare(dep, E_UNEQUAL, &symbol_no);
+			dep = expr_eliminate_dups(expr_transform(dep));
+			dep2 = basedep;
+			expr_eliminate_eq(&dep, &dep2);
+			if (!expr_is_yes(dep2)) {
+				/* Not superset, quit */
+				break;
+			}
+			/* Superset, put in submenu */
+		next:
+			_menu_finalize(menu, false);
+			menu->parent = parent;
+			last_menu = menu;
+		}
+		if (last_menu) {
+			parent->list = parent->next;
+			parent->next = last_menu->next;
+			last_menu->next = NULL;
+		}
+
+		sym->dir_dep.expr = expr_alloc_or(sym->dir_dep.expr, parent->dep);
+	}
+	for (menu = parent->list; menu; menu = menu->next) {
+		/*
+		 * This code serves two purposes:
+		 *
+		 * (1) Flattening 'if' blocks, which do not specify a submenu
+		 *     and only add dependencies.
+		 *
+		 *     (Automatic submenu creation might still create a submenu
+		 *     from an 'if' before this code runs.)
+		 *
+		 * (2) "Undoing" any automatic submenus created earlier below
+		 *     promptless symbols.
+		 *
+		 * Before:
+		 *
+		 *	A
+		 *	if ... (or promptless symbol)
+		 *	 +-B
+		 *	 +-C
+		 *	D
+		 *
+		 * After:
+		 *
+		 *	A
+		 *	if ... (or promptless symbol)
+		 *	B
+		 *	C
+		 *	D
+		 */
+		if (menu->list && (!menu->prompt || !menu->prompt->text)) {
+			for (last_menu = menu->list; ; last_menu = last_menu->next) {
+				last_menu->parent = parent;
+				if (!last_menu->next)
+					break;
+			}
+			last_menu->next = menu->next;
+			menu->next = menu->list;
+			menu->list = NULL;
+		}
+	}
+
+	if (sym && !(sym->flags & SYMBOL_WARNED)) {
+		if (sym->type == S_UNKNOWN)
+			menu_warn(parent, "config symbol defined without type");
+
+		/* Check properties connected to this symbol */
+		sym_check_prop(sym);
+		sym->flags |= SYMBOL_WARNED;
+	}
+}
+
+void menu_finalize(void)
+{
+	_menu_finalize(&rootmenu, false);
+}
+
+bool menu_has_prompt(const struct menu *menu)
+{
+	if (!menu->prompt)
+		return false;
+	return true;
+}
+
+/*
+ * Determine if a menu is empty.
+ * A menu is considered empty if it contains no or only
+ * invisible entries.
+ */
+bool menu_is_empty(struct menu *menu)
+{
+	struct menu *child;
+
+	for (child = menu->list; child; child = child->next) {
+		if (menu_is_visible(child))
+			return(false);
+	}
+	return(true);
+}
+
+bool menu_is_visible(struct menu *menu)
+{
+	struct menu *child;
+	struct symbol *sym;
+	tristate visible;
+
+	if (!menu->prompt)
+		return false;
+
+	if (menu->visibility) {
+		if (expr_calc_value(menu->visibility) == no)
+			return false;
+	}
+
+	sym = menu->sym;
+	if (sym) {
+		sym_calc_value(sym);
+		visible = menu->prompt->visible.tri;
+	} else
+		visible = menu->prompt->visible.tri = expr_calc_value(menu->prompt->visible.expr);
+
+	if (visible != no)
+		return true;
+
+	if (!sym || sym_get_tristate_value(menu->sym) == no)
+		return false;
+
+	for (child = menu->list; child; child = child->next)
+		if (menu_is_visible(child))
+			return true;
+
+	return false;
+}
+
+const char *menu_get_prompt(const struct menu *menu)
+{
+	if (menu->prompt)
+		return menu->prompt->text;
+	else if (menu->sym)
+		return menu->sym->name;
+	return NULL;
+}
+
+/**
+ * menu_get_parent_menu - return the parent menu or NULL
+ * @menu: pointer to the menu
+ * return: the parent menu, or NULL if there is no parent.
+ */
+struct menu *menu_get_parent_menu(struct menu *menu)
+{
+	for (menu = menu->parent; menu; menu = menu->parent)
+		if (menu->type == M_MENU)
+			return menu;
+
+	return NULL;
+}
+
+/**
+ * menu_get_menu_or_parent_menu - return the parent menu or the menu itself
+ * @menu: pointer to the menu
+ * return: the parent menu. If the given argument is already a menu, return
+ *         itself.
+ */
+struct menu *menu_get_menu_or_parent_menu(struct menu *menu)
+{
+	enum prop_type type;
+
+	for (; menu != &rootmenu; menu = menu->parent) {
+		type = menu->prompt ? menu->prompt->type : 0;
+		if (type == P_MENU)
+			break;
+	}
+	return menu;
+}
+
+static void get_def_str(struct gstr *r, const struct menu *menu)
+{
+	str_printf(r, "Defined at %s:%d\n",
+		   menu->filename, menu->lineno);
+}
+
+static void get_dep_str(struct gstr *r, const struct expr *expr,
+			const char *prefix)
+{
+	if (!expr_is_yes(expr)) {
+		str_append(r, prefix);
+		expr_gstr_print(expr, r);
+		str_append(r, "\n");
+	}
+}
+
+int __attribute__((weak)) get_jump_key_char(void)
+{
+	return -1;
+}
+
+static void get_prompt_str(struct gstr *r, struct property *prop,
+			   struct list_head *head)
+{
+	int i, j;
+	struct menu *submenu[8], *menu, *location = NULL;
+	struct jump_key *jump = NULL;
+
+	str_printf(r, "  Prompt: %s\n", prop->text);
+
+	get_dep_str(r, prop->menu->dep, "  Depends on: ");
+	/*
+	 * Most prompts in Linux have visibility that exactly matches their
+	 * dependencies. For these, we print only the dependencies to improve
+	 * readability. However, prompts with inline "if" expressions and
+	 * prompts with a parent that has a "visible if" expression have
+	 * differing dependencies and visibility. In these rare cases, we
+	 * print both.
+	 */
+	if (!expr_eq(prop->menu->dep, prop->visible.expr))
+		get_dep_str(r, prop->visible.expr, "  Visible if: ");
+
+	menu = prop->menu;
+	for (i = 0; menu != &rootmenu && i < 8; menu = menu->parent) {
+		submenu[i++] = menu;
+		if (location == NULL && menu_is_visible(menu))
+			location = menu;
+	}
+	if (head && location) {
+		jump = xmalloc(sizeof(struct jump_key));
+		jump->target = location;
+		list_add_tail(&jump->entries, head);
+	}
+
+	str_printf(r, "  Location:\n");
+	for (j = 0; --i >= 0; j++) {
+		int jk = -1;
+		int indent = 2 * j + 4;
+
+		menu = submenu[i];
+		if (jump && menu == location) {
+			jump->offset = strlen(r->s);
+			jk = get_jump_key_char();
+		}
+
+		if (jk >= 0) {
+			str_printf(r, "(%c)", jk);
+			indent -= 3;
+		}
+
+		str_printf(r, "%*c-> %s", indent, ' ', menu_get_prompt(menu));
+		if (menu->sym) {
+			str_printf(r, " (%s [=%s])", menu->sym->name ?
+				menu->sym->name : "<choice>",
+				sym_get_string_value(menu->sym));
+		}
+		str_append(r, "\n");
+	}
+}
+
+static void get_symbol_props_str(struct gstr *r, struct symbol *sym,
+				 enum prop_type tok, const char *prefix)
+{
+	bool hit = false;
+	struct property *prop;
+
+	for_all_properties(sym, prop, tok) {
+		if (!hit) {
+			str_append(r, prefix);
+			hit = true;
+		} else
+			str_printf(r, " && ");
+		expr_gstr_print(prop->expr, r);
+	}
+	if (hit)
+		str_append(r, "\n");
+}
+
+/*
+ * head is optional and may be NULL
+ */
+static void get_symbol_str(struct gstr *r, struct symbol *sym,
+		    struct list_head *head)
+{
+	struct property *prop;
+	struct menu *menu;
+
+	if (sym && sym->name) {
+		str_printf(r, "Symbol: %s [=%s]\n", sym->name,
+			   sym_get_string_value(sym));
+		str_printf(r, "Type  : %s\n", sym_type_name(sym->type));
+		if (sym->type == S_INT || sym->type == S_HEX) {
+			prop = sym_get_range_prop(sym);
+			if (prop) {
+				str_printf(r, "Range : ");
+				expr_gstr_print(prop->expr, r);
+				str_append(r, "\n");
+			}
+		}
+	}
+
+	/* Print the definitions with prompts before the ones without */
+	list_for_each_entry(menu, &sym->menus, link) {
+		if (menu->prompt) {
+			get_def_str(r, menu);
+			get_prompt_str(r, menu->prompt, head);
+		}
+	}
+
+	list_for_each_entry(menu, &sym->menus, link) {
+		if (!menu->prompt) {
+			get_def_str(r, menu);
+			get_dep_str(r, menu->dep, "  Depends on: ");
+		}
+	}
+
+	get_symbol_props_str(r, sym, P_SELECT, "Selects: ");
+	if (sym->rev_dep.expr) {
+		expr_gstr_print_revdep(sym->rev_dep.expr, r, yes, "Selected by [y]:\n");
+		expr_gstr_print_revdep(sym->rev_dep.expr, r, mod, "Selected by [m]:\n");
+		expr_gstr_print_revdep(sym->rev_dep.expr, r, no, "Selected by [n]:\n");
+	}
+
+	get_symbol_props_str(r, sym, P_IMPLY, "Implies: ");
+	if (sym->implied.expr) {
+		expr_gstr_print_revdep(sym->implied.expr, r, yes, "Implied by [y]:\n");
+		expr_gstr_print_revdep(sym->implied.expr, r, mod, "Implied by [m]:\n");
+		expr_gstr_print_revdep(sym->implied.expr, r, no, "Implied by [n]:\n");
+	}
+
+	str_append(r, "\n\n");
+}
+
+struct gstr get_relations_str(struct symbol **sym_arr, struct list_head *head)
+{
+	struct symbol *sym;
+	struct gstr res = str_new();
+	int i;
+
+	for (i = 0; sym_arr && (sym = sym_arr[i]); i++)
+		get_symbol_str(&res, sym, head);
+	if (!i)
+		str_append(&res, "No matches found.\n");
+	return res;
+}
+
+
+void menu_get_ext_help(struct menu *menu, struct gstr *help)
+{
+	struct symbol *sym = menu->sym;
+	const char *help_text = nohelp_text;
+
+	if (menu->help) {
+		if (sym->name)
+			str_printf(help, "%s%s:\n\n", CONFIG_, sym->name);
+		help_text = menu->help;
+	}
+	str_printf(help, "%s\n", help_text);
+	if (sym)
+		get_symbol_str(help, sym, NULL);
+}
+
+/**
+ * menu_dump - dump all menu entries in a tree-like format
+ */
+void menu_dump(void)
+{
+	struct menu *menu = &rootmenu;
+	unsigned long long bits = 0;
+	int indent = 0;
+
+	while (menu) {
+
+		for (int i = indent - 1; i >= 0; i--) {
+			if (bits & (1ULL << i)) {
+				if (i > 0)
+					printf("|   ");
+				else
+					printf("|-- ");
+			} else {
+				if (i > 0)
+					printf("    ");
+				else
+					printf("`-- ");
+			}
+		}
+
+		switch (menu->type) {
+		case M_CHOICE:
+			printf("choice \"%s\"\n", menu->prompt->text);
+			break;
+		case M_COMMENT:
+			printf("comment \"%s\"\n", menu->prompt->text);
+			break;
+		case M_IF:
+			printf("if\n");
+			break;
+		case M_MENU:
+			printf("menu \"%s\"", menu->prompt->text);
+			if (!menu->sym) {
+				printf("\n");
+				break;
+			}
+			printf(" + ");
+			/* fallthrough */
+		case M_NORMAL:
+			printf("symbol %s\n", menu->sym->name);
+			break;
+		}
+		if (menu->list) {
+			bits <<= 1;
+			menu = menu->list;
+			if (menu->next)
+				bits |= 1;
+			else
+				bits &= ~1;
+			indent++;
+			continue;
+		}
+
+		while (menu && !menu->next) {
+			menu = menu->parent;
+			bits >>= 1;
+			indent--;
+		}
+
+		if (menu) {
+			menu = menu->next;
+			if (menu->next)
+				bits |= 1;
+			else
+				bits &= ~1;
+		}
+	}
+}