Patch "kconfig: add warn-unknown-symbols sanity check" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    kconfig: add warn-unknown-symbols sanity check

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     kconfig-add-warn-unknown-symbols-sanity-check.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 1af59b231d8628d52a66f45fd98a61265158cf2a
Author: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Date:   Wed Aug 30 09:49:36 2023 +0900

    kconfig: add warn-unknown-symbols sanity check
    
    [ Upstream commit 7cd343008b967423b06af8f6d3236749c67d12e8 ]
    
    Introduce KCONFIG_WARN_UNKNOWN_SYMBOLS environment variable,
    which makes Kconfig warn about unknown config symbols.
    
    This is especially useful for continuous kernel uprevs when
    some symbols can be either removed or renamed between kernel
    releases (which can go unnoticed otherwise).
    
    By default KCONFIG_WARN_UNKNOWN_SYMBOLS generates warnings,
    which are non-terminal. There is an additional environment
    variable KCONFIG_WERROR that overrides this behaviour and
    turns warnings into errors.
    
    Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
    Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
    Stable-dep-of: a409fc1463d6 ("kconfig: fix memory leak in sym_warn_unmet_dep()")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/Documentation/kbuild/kconfig.rst b/Documentation/kbuild/kconfig.rst
index 5967c79c3baa7..eee0d298774ab 100644
--- a/Documentation/kbuild/kconfig.rst
+++ b/Documentation/kbuild/kconfig.rst
@@ -54,6 +54,15 @@ KCONFIG_OVERWRITECONFIG
 If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
 break symlinks when .config is a symlink to somewhere else.
 
+KCONFIG_WARN_UNKNOWN_SYMBOLS
+----------------------------
+This environment variable makes Kconfig warn about all unrecognized
+symbols in the config input.
+
+KCONFIG_WERROR
+--------------
+If set, Kconfig treats warnings as errors.
+
 `CONFIG_`
 ---------
 If you set `CONFIG_` in the environment, Kconfig will prefix all symbols
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index 886698a5afba1..02ac250b8fe9e 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -349,7 +349,11 @@ int conf_read_simple(const char *name, int def)
 	char *p, *p2;
 	struct symbol *sym;
 	int i, def_flags;
+	const char *warn_unknown;
+	const char *werror;
 
+	warn_unknown = getenv("KCONFIG_WARN_UNKNOWN_SYMBOLS");
+	werror = getenv("KCONFIG_WERROR");
 	if (name) {
 		in = zconf_fopen(name);
 	} else {
@@ -439,6 +443,10 @@ int conf_read_simple(const char *name, int def)
 			if (def == S_DEF_USER) {
 				sym = sym_find(line + 2 + strlen(CONFIG_));
 				if (!sym) {
+					if (warn_unknown)
+						conf_warning("unknown symbol: %s",
+							     line + 2 + strlen(CONFIG_));
+
 					conf_set_changed(true);
 					continue;
 				}
@@ -473,7 +481,7 @@ int conf_read_simple(const char *name, int def)
 
 			sym = sym_find(line + strlen(CONFIG_));
 			if (!sym) {
-				if (def == S_DEF_AUTO)
+				if (def == S_DEF_AUTO) {
 					/*
 					 * Reading from include/config/auto.conf
 					 * If CONFIG_FOO previously existed in
@@ -481,8 +489,13 @@ int conf_read_simple(const char *name, int def)
 					 * include/config/FOO must be touched.
 					 */
 					conf_touch_dep(line + strlen(CONFIG_));
-				else
+				} else {
+					if (warn_unknown)
+						conf_warning("unknown symbol: %s",
+							     line + strlen(CONFIG_));
+
 					conf_set_changed(true);
+				}
 				continue;
 			}
 
@@ -521,6 +534,10 @@ int conf_read_simple(const char *name, int def)
 	}
 	free(line);
 	fclose(in);
+
+	if (conf_warnings && werror)
+		exit(1);
+
 	return 0;
 }