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: HONG Yifan <[e-mail]>
Signed-off-by: Masahiro Yamada <[e-mail]>

scripts/kconfig/symbol.c

···
 {
 	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) {
···
 	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

···
-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"