The patch titled Subject: revert "kbuild: fix -Wimplicit-function-declaration in license_is_gpl_compatible" has been added to the -mm mm-hotfixes-unstable branch. Its filename is revert-kbuild-fix-wimplicit-function-declaration-in-license_is_gpl_compatible.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/revert-kbuild-fix-wimplicit-function-declaration-in-license_is_gpl_compatible.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Subject: revert "kbuild: fix -Wimplicit-function-declaration in license_is_gpl_compatible" Date: Mon Nov 28 01:21:40 PM PST 2022 It causes build failures with unusual CC/HOSTCC combinations. Quoting https://lkml.kernel.org/r/A222B1E6-69B8-4085-AD1B-27BDB72CA971@xxxxxxxxxxxxx: HOSTCC scripts/mod/modpost.o - due to target missing In file included from include/linux/string.h:5, from scripts/mod/../../include/linux/license.h:5, from scripts/mod/modpost.c:24: include/linux/compiler.h:246:10: fatal error: asm/rwonce.h: No such file or directory 246 | #include <asm/rwonce.h> | ^~~~~~~~~~~~~~ compilation terminated. ... The problem is that HOSTCC is not necessarily the same compiler or even architecture as CC and pulling in <linux/compiler.h> or <asm/rwonce.h> files indirectly isn't a good idea then. My toolchain is providing HOSTCC = gcc (MacPorts) and CC = arm-linux-gnueabihf (built from gcc source) and all running on Darwin. If I change the include to <string.h> I can then "HOSTCC scripts/mod/modpost.c" but then it fails for "CC kernel/module/main.c" not finding <string.h>: CC kernel/module/main.o - due to target missing In file included from kernel/module/main.c:43:0: ./include/linux/license.h:5:20: fatal error: string.h: No such file or directory #include <string.h> ^ compilation terminated. Reportd-by: "H. Nikolaus Schaller" <hns@xxxxxxxxxxxxx> Cc: Sam James <sam@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/license.h | 2 -- 1 file changed, 2 deletions(-) --- a/include/linux/license.h~revert-kbuild-fix-wimplicit-function-declaration-in-license_is_gpl_compatible +++ a/include/linux/license.h @@ -2,8 +2,6 @@ #ifndef __LICENSE_H #define __LICENSE_H -#include <linux/string.h> - static inline int license_is_gpl_compatible(const char *license) { return (strcmp(license, "GPL") == 0 _ Patches currently in -mm which might be from akpm@xxxxxxxxxxxxxxxxxxxx are mm-replace-vm_warn_on-to-pr_warn-if-the-node-is-offline-with-__gfp_thisnode-v4-fix.patch mm-replace-vm_warn_on-to-pr_warn-if-the-node-is-offline-with-__gfp_thisnode-v4-fix-2.patch revert-kbuild-fix-wimplicit-function-declaration-in-license_is_gpl_compatible.patch mm-memremap_pages-replace-zone_device_page_init-with-pgmap_request_folios-fix.patch mm-gup-remove-foll_migration-fix.patch mm-memremap-introduce-pgmap_request_folio-using-pgmap-offsets-fix.patch mm-memremap-introduce-pgmap_request_folio-using-pgmap-offsets-fix-2.patch kasan-allow-sampling-page_alloc-allocations-for-hw_tags-fix.patch mm-hugetlb-convert-move_hugetlb_state-to-folios-fix.patch mm-introduce-encoded-page-pointers-with-embedded-extra-bits-fix.patch mm-delay-page_remove_rmap-until-after-the-tlb-has-been-flushed-fix.patch mm-document-sys-class-bdi-bdi-min_bytes-knob-fix.patch mm-document-sys-class-bdi-bdi-max_ratio_fine-knob-fix.patch mm-document-sys-class-bdi-bdi-min_ratio_fine-knob-fix.patch