From: Andrew Jones Date: Wed, 27 May 2026 14:27:03 +0000 (-0500) Subject: kconfig: add kconfig-sym-check static checker X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=f58316a441b4626324993db585fa4b7b7c780fac;p=thirdparty%2Flinux.git kconfig: add kconfig-sym-check static checker Add 'make kconfig-sym-check', a static checker that finds Kconfig symbols referenced in expressions (select, depends on, default, etc.) but never defined via config/menuconfig anywhere in the tree. New dangling symbols are reported as errors (exit 1) unless they are listed in an exclusion file, e.g. KCONFIG_SYM_CHECK_EXCLUDES=sym-check-excludes make kconfig-sym-check The exclusion file lists one symbol per line; blank lines and lines starting with '#' are ignored. The checker also warns about uppercase N/Y/M used as tristate literal values following the same logic as checkpatch. This new static checker is the script used for [1] with a few improvements to avoid some false positives. Link: https://bugzilla.kernel.org/show_bug.cgi?id=216748 [1] Assisted-by: Claude:claude-sonnet-4-6 Signed-off-by: Andrew Jones Acked-by: Andy Shevchenko Acked-by: Randy Dunlap Tested-by: Randy Dunlap Tested-by: Julian Braha Tested-by: Nicolas Schier Acked-by: Nicolas Schier Link: https://patch.msgid.link/20260527142703.107110-1-andrew.jones@linux.dev Signed-off-by: Nathan Chancellor --- diff --git a/Makefile b/Makefile index 857f08dcc952..37fdb454b637 100644 --- a/Makefile +++ b/Makefile @@ -293,6 +293,7 @@ version_h := include/generated/uapi/linux/version.h clean-targets := %clean mrproper cleandocs no-dot-config-targets := $(clean-targets) \ cscope gtags TAGS tags help% %docs check% coccicheck \ + kconfig-sym-check \ $(version_h) headers headers_% archheaders archscripts \ %asm-generic kernelversion %src-pkg dt_binding_check \ outputmakefile rustavailable rustfmt rustfmtcheck \ @@ -1800,14 +1801,15 @@ help: echo ' (default: $(INSTALL_HDR_PATH))'; \ echo '' @echo 'Static analysers:' - @echo ' checkstack - Generate a list of stack hogs and consider all functions' - @echo ' with a stack size larger than MINSTACKSIZE (default: 100)' - @echo ' versioncheck - Sanity check on version.h usage' - @echo ' includecheck - Check for duplicate included header files' - @echo ' headerdep - Detect inclusion cycles in headers' - @echo ' coccicheck - Check with Coccinelle' - @echo ' clang-analyzer - Check with clang static analyzer' - @echo ' clang-tidy - Check with clang-tidy' + @echo ' checkstack - Generate a list of stack hogs and consider all functions' + @echo ' with a stack size larger than MINSTACKSIZE (default: 100)' + @echo ' versioncheck - Sanity check on version.h usage' + @echo ' includecheck - Check for duplicate included header files' + @echo ' headerdep - Detect inclusion cycles in headers' + @echo ' coccicheck - Check with Coccinelle' + @echo ' kconfig-sym-check - Check for dangling Kconfig symbol references' + @echo ' clang-analyzer - Check with clang static analyzer' + @echo ' clang-tidy - Check with clang-tidy' @echo '' @echo 'Tools:' @echo ' nsdeps - Generate missing symbol namespace dependencies' @@ -2227,7 +2229,7 @@ endif # Scripts to check various things for consistency # --------------------------------------------------------------------------- -PHONY += includecheck versioncheck coccicheck +PHONY += includecheck versioncheck coccicheck kconfig-sym-check includecheck: find $(srctree)/* $(RCS_FIND_IGNORE) \ @@ -2242,6 +2244,9 @@ versioncheck: coccicheck: $(Q)$(BASH) $(srctree)/scripts/$@ +kconfig-sym-check: + $(Q)$(PERL) $(srctree)/scripts/kconfig/kconfig-sym-check.pl $(srctree) $(KCONFIG_SYM_CHECK_EXCLUDES) + PHONY += checkstack kernelrelease kernelversion image_name # UML needs a little special treatment here. It wants to use the host diff --git a/scripts/kconfig/kconfig-sym-check.pl b/scripts/kconfig/kconfig-sym-check.pl new file mode 100755 index 000000000000..daa5285fdefc --- /dev/null +++ b/scripts/kconfig/kconfig-sym-check.pl @@ -0,0 +1,132 @@ +#!/usr/bin/env perl +# SPDX-License-Identifier: GPL-2.0 + +use warnings; +use strict; + +my $srctree = shift @ARGV; +unless (defined $srctree) { + $srctree = `git rev-parse --show-toplevel 2>/dev/null`; + chomp $srctree; + my $msg = "Usage: $0 [excludes file]\n"; + $msg .= "Please provide ."; + $msg .= " Is it '$srctree'?" if $srctree; + $msg .= "\n"; + die $msg; +} +my $kconfig_sym_check_excludes = defined $ARGV[0] ? $ARGV[0] : undef; + +sub indent_depth { + my ($ws) = @_; + my $col = 0; + for my $c (split //, $ws) { + $col = $c eq "\t" ? int($col / 8) * 8 + 8 : $col + 1; + } + return $col; +} + +my @files = `git -C \Q$srctree\E ls-files '*Kconfig*' 2>/dev/null`; +if (@files) { + chomp @files; + @files = map { "$srctree/$_" } @files; +} else { + @files = `find \Q$srctree\E -name '*Kconfig*'`; + chomp @files; +} + +@files = grep { !m{/scripts/kconfig/tests/} } @files; + +my %configs = (); +my %refs = (); + +foreach my $file (@files) { + open F, $file or die "Cannot open $file: $!"; + + my $help = 0; + my $help_level; + my $level; + + while () { + chomp; + + while (/\\\s*$/) { + s/\\\s*$/ /; + my $cont = // last; + chomp $cont; + $_ .= $cont; + } + + next if /^\s*$/; + next if /^\s*#/; + + /^(\s*)/; + $level = indent_depth($1); + + if ($help && $level < $help_level) { + $help = 0; + } + + next if ($help); + + if (/^\s*(help|\-\-\-help\-\-\-)$/) { + $help = 1; + my $next; + while (defined($next = )) { + last unless $next =~ /^\s*(?:#.*)?$/; + } + last unless defined $next; + $next =~ /^(\s*)/; + if (indent_depth($1) >= $level) { + $help_level = indent_depth($1); + } else { + $help = 0; + } + $_ = $next; + redo; + } + + if (/^\s*(config|menuconfig)\s+([a-zA-Z0-9_]+)\s*(#.*)?$/) { + $configs{$2}++; + next; + } + + if (/^\s*(default|def_bool|def_tristate|select|depends\s+on|imply|visible\s+if|range|if|bool|tristate|int|hex|string|prompt)\s+(.+)\s*$/) { + my $s = $2; + $s =~ s/"(?:[^"\\]|\\.)*"|'(?:[^'\\]|\\.)*'//g; + $s =~ s/#.*//; + $s =~ s/\$\((?:[^()]*|\((?:[^()]*|\([^()]*\))*\))*\)//g; + $s =~ s/%%[^%]*%%//g; + my @syms = split /[^a-zA-Z0-9_]+/, $s; + map { + $refs{$_}++ if (/[a-zA-Z]/ && $_ ne "if" && $_ ne "y" && $_ ne "n" && $_ ne "m" && !/^0[xX][0-9a-fA-F]+$/); + } @syms + } + } + + close F; +} + +my %known_syms = (); +if (defined $kconfig_sym_check_excludes) { + my $file = $kconfig_sym_check_excludes; + open(F, "<", $file) or die "Cannot open $file: $!"; + while () { + chomp; + next if /^\s*$/; + next if /^\s*#/; + $known_syms{$1}++ if (/^\s*([a-zA-Z0-9_]+)\s*(#.*)?$/); + } +} + +my $ret = 0; +foreach my $k (sort keys %refs) { + next if (exists $configs{$k} || exists $known_syms{$k}); + + print "$k"; + print " - warning: '$k' is probably not what you want; Kconfig tristate literals are always lowercase ('n', 'y', 'm')" if ($k eq "N" || $k eq "Y" || $k eq "M"); + print "\n"; + + $ret = 1; +} + +exit $ret;