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Vincent Mailhol 660e899103
kbuild: remove gcc's -Wtype-limits 
W=2 builds are heavily polluted by the -Wtype-limits warning.

Here are some W=12 statistics on Linux v6.19-rc1 for an x86_64
defconfig (with just CONFIG_WERROR set to "n") using gcc 14.3.1:

	 Warning name			count	percent
	-------------------------------------------------
	 -Wlogical-op			    2	  0.00 %
	 -Wmaybe-uninitialized		  138	  0.20 %
	 -Wunused-macros		  869	  1.24 %
	 -Wmissing-field-initializers	 1418	  2.02 %
	 -Wshadow			 2234	  3.19 %
	 -Wtype-limits			65378	 93.35 %
	-------------------------------------------------
	 Total				70039	100.00 %

As we can see, -Wtype-limits represents the vast majority of all
warnings. The reason behind this is that these warnings appear in
some common header files, meaning that some unique warnings are
repeated tens of thousands of times (once per header inclusion).

Add to this the fact that each warning is coupled with a dozen lines
detailing some macro expansion. The end result is that the W=2 output
is just too bloated and painful to use.

Three years ago, I proposed in [1] modifying one such header to
silence that noise. Because the code was not faulty, Linus rejected
the idea and instead suggested simply removing that warning.

At that time, I could not bring myself to send such a patch because,
despite its problems, -Wtype-limits would still catch the below bug:

	unsigned int ret;

	ret = check();
	if (ret < 0)
		error();

Meanwhile, based on another suggestion from Linus, I added a new check
to sparse [2] that would catch the above bug without the useless spam.

With this, remove gcc's -Wtype-limits. People who still want to catch
incorrect comparisons between unsigned integers and zero can now use
sparse instead.

On a side note, clang also has a -Wtype-limits warning but:

  * it is not enabled in the kernel at the moment because, contrary to
    gcc, clang did not include it under -Wextra.

  * it does not warn if the code results from a macro expansion. So,
    if activated, it would not cause as much spam as gcc does.

  * -Wtype-limits is split into four sub-warnings [3] meaning that if
    it were to be activated, we could select which one to keep.

So there is no present need to explicitly disable -Wtype-limits in
clang.

[1] linux/bits.h: GENMASK_INPUT_CHECK: reduce W=2 noise by 31% treewide
Link: https://lore.kernel.org/all/20220308141201.2343757-1-mailhol.vincent@wanadoo.fr/

[2] Warn about "unsigned value that used to be signed against zero"
Link: https://lore.kernel.org/all/20250921061337.3047616-1-mailhol@kernel.org/

[3] clang's -Wtype-limits
Link: https://clang.llvm.org/docs/DiagnosticsReference.html#wtype-limits

Reviewed-by: Nicolas Schier <nsc@kernel.org>
Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
Link: https://patch.msgid.link/20251220-remove_wtype-limits-v3-1-24b170af700e@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2026-01-05 16:54:14 -07:00
..
atomic atomic: Skip alignment check for try_cmpxchg() old arg 2025-10-21 12:31:56 +02:00
bash-completion kbuild: add Kbuild bash completion 2025-03-15 21:22:52 +09:00
basic integer-wrap: Force full rebuild when .scl file changes 2025-05-08 09:42:06 -07:00
clang-tools scripts/clang-tools: Handle included .c files in gen_compile_commands 2025-11-08 12:18:00 +01:00
coccinelle coccinelle: Drop pm_runtime_barrier() error code checks 2025-12-04 20:38:13 +01:00
crypto lib/crypto: tests: Add KUnit tests for POLYVAL 2025-11-11 11:07:52 -08:00
dtc scripts: dt_to_config: fix grammar and a typo in --help text 2025-09-26 15:53:30 -05:00
dummy-tools kbuild: dummy-tools: pretend we understand -fpatchable-function-entry 2023-11-01 23:24:56 +09:00
gcc-plugins gcc-plugins: Remove TODO_verify_il for GCC >= 16 2025-09-23 13:59:39 -07:00
gdb scripts/gdb/symbols: make BPF debug info available to GDB 2025-11-20 14:03:42 -08:00
gendwarfksyms gendwarfksyms: Skip files with no exports 2025-11-11 20:37:11 +01:00
genksyms genksyms: Fix enum consts from a reference affecting new values 2025-06-07 14:38:07 +09:00
include scripts: import more list macros 2024-10-07 02:12:27 +09:00
ipe scripts: ipe: polgen: remove redundant close and error exit path 2024-11-19 13:57:03 -08:00
kconfig kconfig: move XPM icons to separate files 2025-12-19 13:34:33 -07:00
ksymoops
livepatch objtool/klp: Only enable --checksum when needed 2025-11-18 09:59:26 +01:00
mod modpost: drop '*_probe' from section check whitelist 2025-12-16 22:12:29 +09:00
package kbuild: install-extmod-build: Properly fix CC expansion when ccache is used 2025-11-11 22:31:34 -07:00
selinux docs: Remove remainders of reiserfs 2025-08-18 10:45:43 -06:00
tracing scripts/tracing: Remove scripts/tracing/draw_functrace.py 2025-03-20 07:02:21 -04:00
.gitignore scripts: add tracepoint-update to the list of ignores files 2025-10-29 08:46:05 -04:00
as-version.sh
asn1_compiler.c
bloat-o-meter
bootgraph.pl
bpf_doc.py bpf: Finish constification of 1st parameter of bpf_d_path() 2025-10-04 09:05:23 -07:00
build-version kbuild: move init/build-version to scripts/ 2024-07-16 01:08:37 +09:00
cc-can-link.sh kbuild: don't enable CC_CAN_LINK if the dummy program generates warnings 2025-11-14 20:20:34 +01:00
cc-version.sh
check-function-names.sh kbuild: Check for functions with ambiguous -ffunction-sections section names 2025-11-21 10:04:10 +01:00
check-git
check-sysctl-docs docs: Replace spaces with tabs in check-sysctl-docs 2025-07-23 11:57:05 +02:00
check-uapi.sh check-uapi: Introduce check-uapi.sh 2023-12-29 22:25:20 +09:00
check_extable.sh
checkdeclares.pl
checkincludes.pl
checkkconfigsymbols.py
checkpatch.pl checkpatch: add uninitialized pointer with __free attribute check 2025-12-10 16:07:42 -08:00
checkstack.pl scripts/checkstack.pl: fix no space expression between sp and offset 2023-12-29 12:22:28 -08:00
checksyscalls.sh
checkversion.pl
cleanfile
cleanpatch
coccicheck kbuild: change working directory to external module directory with M= 2024-11-28 08:10:23 +09:00
config kbuild: fix argument parsing in scripts/config 2025-03-15 21:22:42 +09:00
const_structs.checkpatch const_structs.checkpatch: add bin_attribute 2025-06-17 10:44:07 +02:00
decode_stacktrace.sh scripts/decode_stacktrace.sh: fix build ID and PC source parsing 2025-11-09 21:19:45 -08:00
decodecode scripts/decodecode: add support for LoongArch 2023-12-29 12:22:25 -08:00
depmod.sh kbuild: add $(objtree)/ prefix to some in-kernel build artifacts 2024-11-27 09:38:27 +09:00
dev-needs.sh
diffconfig
elf-parse.c sorttable: Move ELF parsing into scripts/elf-parse.[ch] 2025-10-24 16:43:14 -04:00
elf-parse.h sorttable: Move ELF parsing into scripts/elf-parse.[ch] 2025-10-24 16:43:14 -04:00
extract-fwblobs scripts: add script to extract built-in firmware blobs 2025-03-16 22:30:46 -07:00
extract-ikconfig
extract-module-sig.pl
extract-sys-certs.pl
extract-vmlinux extract-vmlinux: Output used decompression method 2025-08-28 15:25:48 -07:00
extract_xc3028.pl
faddr2line scripts/faddr2line: Fix "Argument list too long" error 2025-10-14 14:45:20 -07:00
file-size.sh
gen-crc-consts.py riscv/crc: add "template" for Zbc optimized CRC functions 2025-03-10 09:29:08 -07:00
gen-randstruct-seed.sh
gen_packed_field_checks.c lib: packing: add pack_fields() and unpack_fields() 2024-12-11 20:13:00 -08:00
generate_builtin_ranges.awk kbuild: exclude .rodata.(cst|str)* when building ranges 2025-03-15 21:22:52 +09:00
generate_initcall_order.pl
generate_rust_analyzer.py rust: macros: support proc-macro2, quote and syn 2025-11-24 17:15:50 +01:00
generate_rust_target.rs rust: support Rust >= 1.91.0 target spec 2025-08-31 23:34:34 +02:00
get_dvb_firmware
get_maintainer.pl get_maintainer: stop reporting subsystem status as maintainer role 2025-03-16 22:30:49 -07:00
gfp-translate scripts: fix gfp-translate after ___GFP_*_BITS conversion to an enum 2024-09-01 17:59:01 -07:00
git-resolve.sh git-resolve: add SPDX and copyright line 2025-04-25 15:54:24 +02:00
git.orderFile scripts: Introduce a default git.orderFile 2023-12-29 22:25:20 +09:00
head-object-list.txt openrisc: place exception table at the head of vmlinux 2024-12-10 12:04:19 +00:00
headerdep.pl
headers_install.sh scripts: headers_install.sh: Remove two outdated config leak ignore entries 2025-11-11 16:01:13 +01:00
insert-sys-cert.c
install.sh kbuild: Create INSTALL_PATH directory if it does not exist 2024-07-20 13:34:54 +09:00
integer-wrap-ignore.scl ubsan/overflow: Enable ignorelist parsing and add type filter 2025-03-07 19:58:05 -08:00
jobserver-exec docs: Move the python libraries to tools/lib/python 2025-11-18 09:22:40 -07:00
kallsyms.c kallsyms: Remove KALLSYMS_ABSOLUTE_PERCPU 2025-02-18 10:16:04 +01:00
Kbuild.include kbuild: add $(objtree)/ prefix to some in-kernel build artifacts 2024-11-27 09:38:27 +09:00
Kconfig.include init: deduplicate cc-can-link.sh invocations 2025-11-14 20:20:34 +01:00
kernel-doc scripts/kernel-doc: switch to use kernel-doc.py 2025-04-09 12:10:34 -06:00
kernel-doc.py docs: bring some order to our Python module hierarchy 2025-11-18 09:22:40 -07:00
ld-version.sh kbuild: Make ld-version.sh more robust against version string changes 2024-07-15 03:13:32 +09:00
leaking_addresses.pl leaking_addresses: Provide mechanism to scan binary files 2024-02-29 13:38:03 -08:00
Lindent
link-vmlinux.sh Detect unused tracepoints for v6.19: 2025-12-05 09:37:41 -08:00
macro_checker.py scripts: add macro_checker script to check unused parameters in macros 2024-09-01 20:43:28 -07:00
make_fit.py scripts/make_fit: Print DT name before libfdt errors 2025-03-27 14:03:32 -05:00
Makefile tracing: Add a tracepoint verification check at build time 2025-10-24 16:43:14 -04:00
Makefile.asm-headers kbuild: fix rebuild of generic syscall headers 2024-07-18 10:01:55 -07:00
Makefile.autofdo AutoFDO: Enable machine function split optimization for AutoFDO 2024-11-27 09:38:27 +09:00
Makefile.btf kbuild, bpf: Enable --btf_features=attributes 2025-04-15 11:17:50 -07:00
Makefile.build kbuild: Let kernel-doc.py use PYTHON3 override 2025-11-08 19:42:22 -07:00
Makefile.clang kbuild: clang: Support building UM with SUBARCH=i386 2025-03-04 09:40:13 -08:00
Makefile.clean kbuild: change working directory to external module directory with M= 2024-11-28 08:10:23 +09:00
Makefile.compiler require gcc-8 and binutils-2.30 2025-05-31 08:16:52 -07:00
Makefile.debug kbuild: rust: use -Zdebuginfo-compression 2024-04-02 17:41:22 +02:00
Makefile.defconf kbuild: suppress stdout from merge_config for silent builds 2025-01-10 23:01:21 +09:00
Makefile.dtbinst kbuild: Install dtb files as 0644 in Makefile.dtbinst 2024-06-26 00:18:57 +09:00
Makefile.dtbs kbuild: Ensure .dtbo targets are applied to a base .dtb 2025-11-17 11:27:52 -06:00
Makefile.gcc-plugins stackleak: Split KSTACK_ERASE_CFLAGS from GCC_PLUGINS_CFLAGS 2025-07-21 21:40:57 -07:00
Makefile.headersinst
Makefile.host kbuild: support building external modules in a separate build directory 2024-11-28 08:11:55 +09:00
Makefile.kasan kasan: fix GCC mem-intrinsic prefix with sw tags 2025-08-27 22:45:43 -07:00
Makefile.kcov - The 2 patch series "zram: support algorithm-specific parameters" from 2025-06-02 16:00:26 -07:00
Makefile.kcsan
Makefile.kmsan
Makefile.kstack_erase kstack_erase: Fix missed export of renamed KSTACK_ERASE_CFLAGS 2025-07-29 17:17:46 -07:00
Makefile.lib objtool/klp: Only enable --checksum when needed 2025-11-18 09:59:26 +01:00
Makefile.modfinal tracing: Add warnings for unused tracepoints for modules 2025-10-24 16:43:15 -04:00
Makefile.modinst kbuild: Use objtree for module signing key path 2025-11-08 12:17:58 +01:00
Makefile.modpost modpost: Allow extended modversions without basic MODVERSIONS 2025-01-11 02:36:32 +09:00
Makefile.package kbuild: Add top-level target for building gen_init_cpio 2025-12-19 14:58:11 -07:00
Makefile.propeller kbuild: Fix Propeller build option 2024-11-27 09:38:27 +09:00
Makefile.randstruct
Makefile.ubsan ARM: 2025-05-29 08:10:01 -07:00
Makefile.userprogs kbuild: support 'userldlibs' syntax 2023-11-01 23:26:01 +09:00
Makefile.vdsoinst more s390 updates for 6.10 merge window 2024-05-21 12:09:36 -07:00
Makefile.vmlinux kbuild: Strip trailing padding bytes from modules.builtin.modinfo 2025-11-06 09:50:23 -07:00
Makefile.vmlinux_o kbuild: Check for functions with ambiguous -ffunction-sections section names 2025-11-21 10:04:10 +01:00
Makefile.warn kbuild: remove gcc's -Wtype-limits 2026-01-05 16:54:14 -07:00
makelst
markup_oops.pl
min-tool-version.sh kbuild: Bump minimum version of LLVM for building the kernel to 15.0.0 2025-08-28 16:58:43 -07:00
misc-check scripts/misc-check: update export checks for EXPORT_SYMBOL_FOR_MODULES() 2025-08-26 12:00:17 -07:00
mkcompile_h
mksysmap modpost: Create modalias for builtin modules 2025-09-24 09:10:45 -07:00
mkuboot.sh
module-common.c kbuild: compile constant module information only once 2024-09-07 17:24:08 +09:00
module.lds.S objtool/klp: Introduce klp diff subcommand for diffing object files 2025-10-14 14:50:18 -07:00
modules-check.sh
nsdeps scripts/nsdeps: get 'make nsdeps' working again 2024-12-03 08:22:25 -08:00
objdiff
objdump-func
orc_hash.sh
pahole-version.sh
parse-maintainers.pl
patch-kernel
profile2linkerlist.pl
prune-kernel
recordmcount.c scripts: clean up IA-64 code 2023-12-03 18:51:48 +09:00
recordmcount.h
recordmcount.pl tracing: Remove redundant config HAVE_FTRACE_MCOUNT_RECORD 2025-07-22 20:15:56 -04:00
relocs_check.sh
remove-stale-files selinux: move genheaders to security/selinux/ 2024-10-03 16:07:51 -04:00
rust_is_available.sh rust: document bindgen 0.71.0 regression 2025-01-10 00:17:00 +01:00
rust_is_available_bindgen_0_66.h rust: warn about bindgen versions 0.66.0 and 0.66.1 2024-07-10 10:28:52 +02:00
rust_is_available_bindgen_libclang.h
rust_is_available_bindgen_libclang_concat.h rust: warn on bindgen < 0.69.5 and libclang >= 19.1 2024-11-12 21:26:54 +01:00
rust_is_available_test.py rust: warn on bindgen < 0.69.5 and libclang >= 19.1 2024-11-12 21:26:54 +01:00
rustc-llvm-version.sh kbuild: rust: avoid errors with old rustcs without LLVM patch version 2024-10-28 00:27:16 +01:00
rustc-version.sh kbuild: rust: add CONFIG_RUSTC_VERSION 2024-09-05 22:44:18 +02:00
rustdoc_test_builder.rs rust: use absolute paths in macros referencing core and kernel 2025-05-23 00:12:14 +02:00
rustdoc_test_gen.rs rust: allow clippy::disallowed_names for doctests 2025-11-17 22:53:27 +01:00
setlocalversion setlocalversion: add -e option 2024-11-28 08:11:56 +09:00
show_delta scripts: make python shebangs specific about desired version 2025-03-15 21:19:44 +09:00
sign-file.c sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
sorttable.c sorttable: Move ELF parsing into scripts/elf-parse.[ch] 2025-10-24 16:43:14 -04:00
spdxcheck-test.sh
spdxcheck.py scripts/spdxcheck: Handle license identifiers in Jinja comments 2025-01-08 15:38:33 +01:00
spdxexclude
spelling.txt scripts/spelling.txt: add notifer||notifier to spelling.txt 2025-08-02 12:01:40 -07:00
ssl-common.h sign-file,extract-cert: avoid using deprecated ERR_get_error_line() 2024-09-20 19:49:52 +03:00
stackdelta
stackusage
subarch.include scripts: subarch.include: fix SUBARCH on macOS hosts 2024-09-10 13:56:37 +09:00
syscall.tbl arch: hookup listns() system call 2025-11-03 17:41:18 +01:00
syscallhdr.sh
syscallnr.sh
syscalltbl.sh x86/syscall: Mark exit[_group] syscall handlers __noreturn 2024-06-28 15:23:38 +02:00
tags.sh scripts/tags.sh: allow to use alternative ctags implementation 2025-06-06 05:40:25 +09:00
tools-support-relr.sh
tracepoint-update.c tracing: Fix unused tracepoints when module uses only exported ones 2025-12-09 21:16:07 -05:00
unifdef.c scripts/unifdef: avoid constexpr keyword 2024-04-23 00:09:41 +09:00
ver_linux ver_linux: Remove checks for reiserfsprogs. 2025-06-09 14:53:16 -06:00
verify_builtin_ranges.awk scripts: add verifier script for builtin module range data 2024-09-20 09:21:52 +09:00
xen-hypercalls.sh
xz_wrap.sh xz: adjust arch-specific options for better kernel compression 2024-09-01 20:43:27 -07:00