From f5982cceb34700d15974bc38d667e280902da6d0 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 15 Apr 2024 14:20:32 +0200 Subject: kbuild: turn on -Wextra by default Patch series "kbuild: enable more warnings by default", v3. All the warning fixes I sent for these warnings have been merged into mainline or linux-next, so let's turn them on by default. This patch (of 6): The -Wextra option controls a number of different warnings that differ slightly by compiler version. Some are useful in general, others are better left at W=1 or higher. Based on earlier work, the ones that should be disabled by default are left for the higher warning levels already, and a lot of the useful ones have no remaining output when enabled. Move the -Wextra option up into the set of default-enabled warnings and just rely on the individual ones getting disabled as needed. The -Wunused warning was always grouped with this, so turn it on by default as well, except for the -Wunused-parameter warning that really has no value at all for the kernel since many interfaces have intentionally unused arguments. Link: https://lkml.kernel.org/r/20240415122037.1983124-1-arnd@kernel.org Link: https://lkml.kernel.org/r/20240415122037.1983124-2-arnd@kernel.org Signed-off-by: Arnd Bergmann Acked-by: Nathan Chancellor Cc: Kees Cook Cc: Masahiro Yamada Cc: Nicolas Schier Signed-off-by: Andrew Morton --- scripts/Makefile.extrawarn | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'scripts') diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index c5af566e911a..c247552c192c 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -82,12 +82,14 @@ KBUILD_CFLAGS += $(call cc-option,-Werror=designated-init) # Warn if there is an enum types mismatch KBUILD_CFLAGS += $(call cc-option,-Wenum-conversion) +KBUILD_CFLAGS += -Wextra +KBUILD_CFLAGS += -Wunused + # # W=1 - warnings which may be relevant and do not occur too often # ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),) -KBUILD_CFLAGS += -Wextra -Wunused -Wno-unused-parameter KBUILD_CFLAGS += $(call cc-option, -Wrestrict) KBUILD_CFLAGS += -Wmissing-format-attribute KBUILD_CFLAGS += -Wold-style-definition @@ -190,6 +192,7 @@ else # The following turn off the warnings enabled by -Wextra KBUILD_CFLAGS += -Wno-sign-compare +KBUILD_CFLAGS += -Wno-unused-parameter endif -- cgit v1.2.3 From 2c1460d3b49aa3a05c50dcc371a67b559fc68ac7 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 15 Apr 2024 14:20:33 +0200 Subject: kbuild: remove redundant extra warning flags There is no point in turning individual options off and then on again, or vice versa, as the last one always wins. Now that -Wextra always gets passed first, remove all the redundant lines about warnings that are implied by either -Wall or -Wextra, and keep only the last one that disables it in some configurations. This should not have any effect but keep the Makefile more readable and the command line shorter. Link: https://lkml.kernel.org/r/20240415122037.1983124-3-arnd@kernel.org Signed-off-by: Arnd Bergmann Cc: Kees Cook Cc: Masahiro Yamada Cc: Nathan Chancellor Cc: Nicolas Schier Signed-off-by: Andrew Morton --- scripts/Makefile.extrawarn | 15 --------------- 1 file changed, 15 deletions(-) (limited to 'scripts') diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index c247552c192c..8b3f5b62b837 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -37,11 +37,6 @@ else KBUILD_CFLAGS += -Wno-main endif -# These warnings generated too much noise in a regular build. -# Use make W=1 to enable them (see scripts/Makefile.extrawarn) -KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable) -KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable) - # These result in bogus false positives KBUILD_CFLAGS += $(call cc-disable-warning, dangling-pointer) @@ -90,16 +85,9 @@ KBUILD_CFLAGS += -Wunused # ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),) -KBUILD_CFLAGS += $(call cc-option, -Wrestrict) KBUILD_CFLAGS += -Wmissing-format-attribute -KBUILD_CFLAGS += -Wold-style-definition KBUILD_CFLAGS += -Wmissing-include-dirs -KBUILD_CFLAGS += $(call cc-option, -Wunused-but-set-variable) KBUILD_CFLAGS += $(call cc-option, -Wunused-const-variable) -KBUILD_CFLAGS += $(call cc-option, -Wpacked-not-aligned) -KBUILD_CFLAGS += $(call cc-option, -Wformat-overflow) -KBUILD_CFLAGS += $(call cc-option, -Wformat-truncation) -KBUILD_CFLAGS += $(call cc-option, -Wstringop-truncation) KBUILD_CPPFLAGS += -Wundef KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN1 @@ -150,9 +138,6 @@ ifneq ($(findstring 2, $(KBUILD_EXTRA_WARN)),) KBUILD_CFLAGS += -Wdisabled-optimization KBUILD_CFLAGS += -Wshadow KBUILD_CFLAGS += $(call cc-option, -Wlogical-op) -KBUILD_CFLAGS += -Wmissing-field-initializers -KBUILD_CFLAGS += -Wtype-limits -KBUILD_CFLAGS += $(call cc-option, -Wmaybe-uninitialized) KBUILD_CFLAGS += $(call cc-option, -Wunused-macros) KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN2 -- cgit v1.2.3 From 06bb7fc0feee32d95abc51c3226f598f30eaa261 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 15 Apr 2024 14:20:34 +0200 Subject: kbuild: turn on -Wrestrict by default All known -Wrestrict warnings are addressed now, so don't disable the warning any more. Link: https://lkml.kernel.org/r/20240415122037.1983124-4-arnd@kernel.org Signed-off-by: Arnd Bergmann Cc: Kees Cook Cc: Masahiro Yamada Cc: Nathan Chancellor Cc: Nicolas Schier Signed-off-by: Andrew Morton --- scripts/Makefile.extrawarn | 1 - 1 file changed, 1 deletion(-) (limited to 'scripts') diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 8b3f5b62b837..95466a04d51b 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -98,7 +98,6 @@ else # Suppress them by using -Wno... except for W=1. KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable) KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable) -KBUILD_CFLAGS += $(call cc-disable-warning, restrict) KBUILD_CFLAGS += $(call cc-disable-warning, packed-not-aligned) KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow) KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation) -- cgit v1.2.3 From 908dd508276da13a9b50c208577365d26692eb43 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 15 Apr 2024 14:20:35 +0200 Subject: kbuild: enable -Wformat-truncation on clang This warning option still produces output on gcc but is now clean when building with clang, so enable it conditionally on the compiler for now. As far as I can tell, the remaining warnings with gcc are the result of analysing the code more deeply across inlining, while clang only does this within a function. Link: https://lore.kernel.org/lkml/20240326230511.GA2796782@dev-arch.thelio-3990X/ Link: https://lore.kernel.org/linux-patches/20231002-disable-wformat-truncation-overflow-non-kprintf-v1-1-35179205c8d9@kernel.org/ Link: https://lkml.kernel.org/r/20240415122037.1983124-5-arnd@kernel.org Signed-off-by: Arnd Bergmann Cc: Kees Cook Cc: Masahiro Yamada Cc: Nathan Chancellor Cc: Nicolas Schier Signed-off-by: Andrew Morton --- scripts/Makefile.extrawarn | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'scripts') diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 95466a04d51b..202e26e6f29f 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -100,7 +100,14 @@ KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable) KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable) KBUILD_CFLAGS += $(call cc-disable-warning, packed-not-aligned) KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow) +ifdef CONFIG_CC_IS_GCC KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation) +else +# Clang checks for overflow/truncation with '%p', while GCC does not: +# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111219 +KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow-non-kprintf) +KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation-non-kprintf) +endif KBUILD_CFLAGS += $(call cc-disable-warning, stringop-truncation) KBUILD_CFLAGS += -Wno-override-init # alias for -Wno-initializer-overrides in clang -- cgit v1.2.3 From bd2a70e97a11b0f63a2027e1c376a18c0496908d Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 15 Apr 2024 14:20:36 +0200 Subject: kbuild: enable -Wcast-function-type-strict unconditionally All known function cast warnings are now addressed, so the warning can be enabled globally to catch new ones more quickly. Link: https://lkml.kernel.org/r/20240415122037.1983124-6-arnd@kernel.org Signed-off-by: Arnd Bergmann Reviewed-by: Kees Cook Cc: Masahiro Yamada Cc: Nathan Chancellor Cc: Nicolas Schier Signed-off-by: Andrew Morton --- scripts/Makefile.extrawarn | 1 - 1 file changed, 1 deletion(-) (limited to 'scripts') diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 202e26e6f29f..1d13cecc7cc7 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -129,7 +129,6 @@ endif KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast) KBUILD_CFLAGS += -Wno-tautological-constant-out-of-range-compare KBUILD_CFLAGS += $(call cc-disable-warning, unaligned-access) -KBUILD_CFLAGS += $(call cc-disable-warning, cast-function-type-strict) KBUILD_CFLAGS += -Wno-enum-compare-conditional KBUILD_CFLAGS += -Wno-enum-enum-conversion endif -- cgit v1.2.3