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Wysocki" , linux-kernel@vger.kernel.org, llvm@lists.linux.dev, Justin Stitt Content-Type: text/plain; charset="utf-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable When building x86/defconfig with Clang-18 I encounter the following warning: | init/main.c:189:13: warning: no previous extern declaration for non-stati= c variable 'envp_init' [-Wmissing-variable-declarations] | 189 | const char *envp_init[MAX_INIT_ENVS+2] =3D { "HOME=3D/", "TERM=3D= linux", NULL, }; | init/main.c:189:7: note: declare 'static' if the variable is not intended= to be used outside of this translation unit | 189 | const char *envp_init[MAX_INIT_ENVS+2] =3D { "HOME=3D/", "TERM=3D= linux", NULL, }; Move the extern declaration to a header file so that the compiler can find = it when compiling init/main.c. Add `const` qualifier to extern declaration so that the types match and we follow the One-Definition Rule (ODR). Link: https://github.com/ClangBuiltLinux/linux/issues/1920 Signed-off-by: Justin Stitt --- Note: build-tested only. There's a previous RFC [1] wherein the kernel test robot reported some build errors which lead me to creating this patch which both fixes the errors as well as the -Wmissing-variable-declarations warning. [1]: https://lore.kernel.org/all/20230829-missingvardecl-init-main-c-v1-1-d= df0f1a71215@google.com/ Also, get_maintainer.pl had a hard time finding folks to Cc here, not sure = why. --- include/linux/initrd.h | 2 ++ init/do_mounts_initrd.c | 1 - 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/initrd.h b/include/linux/initrd.h index f1a1f4c92ded..0114f1acbb45 100644 --- a/include/linux/initrd.h +++ b/include/linux/initrd.h @@ -34,4 +34,6 @@ extern unsigned long __initramfs_size; =20 void console_on_rootfs(void); =20 +extern const char *envp_init[]; + #endif /* __LINUX_INITRD_H */ diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c index 425f4bcf4b77..b35c1b0babc2 100644 --- a/init/do_mounts_initrd.c +++ b/init/do_mounts_initrd.c @@ -87,7 +87,6 @@ static void __init handle_initrd(char *root_device_name) { struct subprocess_info *info; static char *argv[] =3D { "linuxrc", NULL, }; - extern char *envp_init[]; int error; =20 pr_warn("using deprecated initrd support, will be removed in 2021.\n"); --- base-commit: 706a741595047797872e669b3101429ab8d378ef change-id: 20230830-missingvardecl2-init-main-c-93dc1013ff8a Best regards, -- Justin Stitt