From 2fd7e7f9317d3048a14026816d081b08ba98ea8e Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 8 Mar 2022 22:56:13 +0100 Subject: [PATCH 1/3] Kbuild: use -Wdeclaration-after-statement The kernel is moving from using `-std=gnu89` to `-std=gnu11`, permitting the use of additional C11 features such as for-loop initial declarations. One contentious aspect of C99 is that it permits mixed declarations and code, and for now at least, it seems preferable to enforce that declarations must come first. These warnings were already enabled in the kernel itself, but not for KBUILD_USERCFLAGS or the compat VDSO on arch/arm64, which uses a separate set of CFLAGS. This patch fixes an existing violation in modpost.c, which is not reported because of the missing flag in KBUILD_USERCFLAGS: | scripts/mod/modpost.c: In function ‘match’: | scripts/mod/modpost.c:837:3: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] | 837 | const char *endp = p + strlen(p) - 1; | | ^~~~~ Signed-off-by: Mark Rutland [arnd: don't add a duplicate flag to the default set, update changelog] Signed-off-by: Arnd Bergmann Reviewed-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Tested-by: Sedat Dilek # LLVM/Clang v13.0.0 (x86-64) Signed-off-by: Masahiro Yamada --- Makefile | 3 ++- arch/arm64/kernel/vdso32/Makefile | 1 + scripts/mod/modpost.c | 4 +++- 3 files changed, 6 insertions(+), 2 deletions(-) diff --git a/Makefile b/Makefile index b9e0b5c604af..cfe400032f96 100644 --- a/Makefile +++ b/Makefile @@ -416,7 +416,8 @@ HOSTCXX = g++ endif export KBUILD_USERCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \ - -O2 -fomit-frame-pointer -std=gnu89 + -O2 -fomit-frame-pointer -std=gnu89 \ + -Wdeclaration-after-statement export KBUILD_USERLDFLAGS := KBUILD_HOSTCFLAGS := $(KBUILD_USERCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS) diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile index abad38c576e1..33cd7ed3f94f 100644 --- a/arch/arm64/kernel/vdso32/Makefile +++ b/arch/arm64/kernel/vdso32/Makefile @@ -76,6 +76,7 @@ VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ -fno-strict-aliasing -fno-common \ -Werror-implicit-function-declaration \ -Wno-format-security \ + -Wdeclaration-after-statement \ -std=gnu89 VDSO_CFLAGS += -O2 # Some useful compiler-dependent flags from top-level Makefile diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 3c27a177b28b..d2b17ed27e6e 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -844,8 +844,10 @@ static int match(const char *sym, const char * const pat[]) { const char *p; while (*pat) { + const char *endp; + p = *pat++; - const char *endp = p + strlen(p) - 1; + endp = p + strlen(p) - 1; /* "*foo*" */ if (*p == '*' && *endp == '*') { -- 2.37.2