Commit 9d0d2660 authored by HONG Yifan's avatar HONG Yifan Committed by Masahiro Yamada
Browse files

kconfig: recursive checks drop file/lineno 



This prevents segfault when getting filename and lineno in recursive
checks.

If the following snippet is found in Kconfig:

[Test code 1]

config FOO
        bool
        depends on BAR
        select BAR

... without BAR defined; then there is a segfault.

  Kconfig:34:error: recursive dependency detected!
  Kconfig:34:	symbol FOO depends on BAR
  make[4]: *** [scripts/kconfig/Makefile:85: allnoconfig] Segmentation fault

This is because of the following. BAR is a fake entry created by
sym_lookup() with prop being NULL. In the recursive check, there is a
NULL check for prop to fall back to stack->sym->prop if stack->prop is
NULL. However, in this case, stack->sym points to the fake BAR entry
created by sym_lookup(), so prop is still NULL. prop was then referenced
without additional NULL checks, causing segfault.

As the previous email thread suggests, the file and lineno for select is
also wrong:

[Test code 2]

config FOO
       bool

config BAR
       bool

config FOO
       bool "FOO"
       depends on BAR
       select BAR

  $ make defconfig
  *** Default configuration is based on 'x86_64_defconfig'
  Kconfig:1:error: recursive dependency detected!
  Kconfig:1: symbol FOO depends on BAR
  Kconfig:4: symbol BAR is selected by FOO
  [...]

Kconfig:4 should be Kconfig:10.

This patch deletes the wrong and segfault-prone filename/lineno
inference completely. With this patch, Test code 1 yields:

error: recursive dependency detected!
	symbol FOO depends on BAR
	symbol BAR is selected by FOO

Signed-off-by: default avatarHONG Yifan <elsk@google.com>
Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
parent 301c1090

scripts/kconfig/symbol.c

+12 −30
Original line number Diff line number Diff line
@@ -1074,10 +1074,9 @@ static void sym_check_print_recursive(struct symbol *last_sym) 
{

	struct dep_stack *stack;

	struct symbol *sym, *next_sym;

	struct menu *menu = NULL;

	struct menu *choice;

	struct property *prop;

	struct dep_stack cv_stack;

	enum prop_type type;



	choice = sym_get_choice_menu(last_sym);

	if (choice) {
@@ -1096,53 +1095,36 @@ static void sym_check_print_recursive(struct symbol *last_sym) 
	for (; stack; stack = stack->next) {

		sym = stack->sym;

		next_sym = stack->next ? stack->next->sym : last_sym;

		prop = stack->prop;

		if (prop == NULL)

			prop = stack->sym->prop;

		type = stack->prop ? stack->prop->type : P_UNKNOWN;



		/* for choice values find the menu entry (used below) */

		if (sym_is_choice(sym) || sym_is_choice_value(sym)) {

			for (prop = sym->prop; prop; prop = prop->next) {

				menu = prop->menu;

				if (prop->menu)

					break;

			}

		}

		if (stack->sym == last_sym)

			fprintf(stderr, "%s:%d:error: recursive dependency detected!\n",

				prop->filename, prop->lineno);

			fprintf(stderr, "error: recursive dependency detected!\n");



		if (sym_is_choice(next_sym)) {

			choice = list_first_entry(&next_sym->menus, struct menu, link);



			fprintf(stderr, "%s:%d:\tsymbol %s is part of choice block at %s:%d\n",

				menu->filename, menu->lineno,

			fprintf(stderr, "\tsymbol %s is part of choice block at %s:%d\n",

				sym->name ? sym->name : "<choice>",

				choice->filename, choice->lineno);

		} else if (stack->expr == &sym->dir_dep.expr) {

			fprintf(stderr, "%s:%d:\tsymbol %s depends on %s\n",

				prop->filename, prop->lineno,

			fprintf(stderr, "\tsymbol %s depends on %s\n",

				sym->name ? sym->name : "<choice>",

				next_sym->name);

		} else if (stack->expr == &sym->rev_dep.expr) {

			fprintf(stderr, "%s:%d:\tsymbol %s is selected by %s\n",

				prop->filename, prop->lineno,

			fprintf(stderr, "\tsymbol %s is selected by %s\n",

				sym->name, next_sym->name);

		} else if (stack->expr == &sym->implied.expr) {

			fprintf(stderr, "%s:%d:\tsymbol %s is implied by %s\n",

				prop->filename, prop->lineno,

			fprintf(stderr, "\tsymbol %s is implied by %s\n",

				sym->name, next_sym->name);

		} else if (stack->expr) {

			fprintf(stderr, "%s:%d:\tsymbol %s %s value contains %s\n",

				prop->filename, prop->lineno,

			fprintf(stderr, "\tsymbol %s %s value contains %s\n",

				sym->name ? sym->name : "<choice>",

				prop_get_type_name(prop->type),

				prop_get_type_name(type),

				next_sym->name);

		} else {

			fprintf(stderr, "%s:%d:\tsymbol %s %s is visible depending on %s\n",

				prop->filename, prop->lineno,

			fprintf(stderr, "\tsymbol %s %s is visible depending on %s\n",

				sym->name ? sym->name : "<choice>",

				prop_get_type_name(prop->type),

				prop_get_type_name(type),

				next_sym->name);

		}

	}

scripts/kconfig/tests/err_recursive_dep/expected_stderr

+18 −18
Original line number Diff line number Diff line 
Kconfig:5:error: recursive dependency detected!

Kconfig:5:	symbol A depends on A

error: recursive dependency detected!

	symbol A depends on A

For a resolution refer to Documentation/kbuild/kconfig-language.rst

subsection "Kconfig recursive dependency limitations"



Kconfig:11:error: recursive dependency detected!

Kconfig:11:	symbol B is selected by B

error: recursive dependency detected!

	symbol B is selected by B

For a resolution refer to Documentation/kbuild/kconfig-language.rst

subsection "Kconfig recursive dependency limitations"



Kconfig:17:error: recursive dependency detected!

Kconfig:17:	symbol C1 depends on C2

Kconfig:21:	symbol C2 depends on C1

error: recursive dependency detected!

	symbol C1 depends on C2

	symbol C2 depends on C1

For a resolution refer to Documentation/kbuild/kconfig-language.rst

subsection "Kconfig recursive dependency limitations"



Kconfig:27:error: recursive dependency detected!

Kconfig:27:	symbol D1 depends on D2

Kconfig:32:	symbol D2 is selected by D1

error: recursive dependency detected!

	symbol D1 depends on D2

	symbol D2 is selected by D1

For a resolution refer to Documentation/kbuild/kconfig-language.rst

subsection "Kconfig recursive dependency limitations"



Kconfig:37:error: recursive dependency detected!

Kconfig:37:	symbol E1 depends on E2

Kconfig:42:	symbol E2 is implied by E1

error: recursive dependency detected!

	symbol E1 depends on E2

	symbol E2 is implied by E1

For a resolution refer to Documentation/kbuild/kconfig-language.rst

subsection "Kconfig recursive dependency limitations"



Kconfig:49:error: recursive dependency detected!

Kconfig:49:	symbol F1 default value contains F2

Kconfig:51:	symbol F2 depends on F1

error: recursive dependency detected!

	symbol F1 default value contains F2

	symbol F2 depends on F1

For a resolution refer to Documentation/kbuild/kconfig-language.rst

subsection "Kconfig recursive dependency limitations"



Kconfig:60:error: recursive dependency detected!

Kconfig:60:	symbol G depends on G

error: recursive dependency detected!

	symbol G depends on G

For a resolution refer to Documentation/kbuild/kconfig-language.rst

subsection "Kconfig recursive dependency limitations"