The patch titled Subject: kernel/Kconfig.kexec: drop select of KEXEC for CRASH_DUMP has been added to the -mm mm-hotfixes-unstable branch. Its filename is kernel-kconfigkexec-drop-select-of-kexec-for-crash_dump.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kernel-kconfigkexec-drop-select-of-kexec-for-crash_dump.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: Baoquan He <bhe@xxxxxxxxxx> Subject: kernel/Kconfig.kexec: drop select of KEXEC for CRASH_DUMP Date: Tue, 28 Nov 2023 13:44:57 +0800 Ignat Korchagin complained that a potential config regression was introduced by commit 89cde455915f ("kexec: consolidate kexec and crash options into kernel/Kconfig.kexec"). Before the commit, CONFIG_CRASH_DUMP has no dependency on CONFIG_KEXEC. After the commit, CRASH_DUMP selects KEXEC. That enforces system to have CONFIG_KEXEC=y as long as CONFIG_CRASH_DUMP=Y which people may not want. In Ignat's case, he sets CONFIG_CRASH_DUMP=y, CONFIG_KEXEC_FILE=y and CONFIG_KEXEC=n because kexec_load interface could have security issue if kernel/initrd has no chance to be signed and verified. CRASH_DUMP has select of KEXEC because Eric, author of above commit, met a LKP report of build failure when posting patch of earlier version. Please see below link to get detail of the LKP report: https://lore.kernel.org/all/3e8eecd1-a277-2cfb-690e-5de2eb7b988e@xxxxxxxxxx/T/#u In fact, that LKP report is triggered because arm's <asm/kexec.h> is wrapped in CONFIG_KEXEC ifdeffery scope. That is wrong. CONFIG_KEXEC controls the enabling/disabling of kexec_load interface, but not kexec feature. Removing the wrongly added CONFIG_KEXEC ifdeffery scope in <asm/kexec.h> of arm allows us to drop the select KEXEC for CRASH_DUMP. Meanwhile, change arch/arm/kernel/Makefile to let machine_kexec.o relocate_kernel.o depend on KEXEC_CORE. Link: https://lkml.kernel.org/r/20231128054457.659452-1-bhe@xxxxxxxxxx Fixes: commit 89cde455915f ("kexec: consolidate kexec and crash options into kernel/Kconfig.kexec") Signed-off-by: Baoquan He <bhe@xxxxxxxxxx> Reported-by: Ignat Korchagin <ignat@xxxxxxxxxxxxxx> Tested-by: Ignat Korchagin <ignat@xxxxxxxxxxxxxx> [compile-time only] Tested-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx> Reviewed-by: Eric DeVolder <eric_devolder@xxxxxxxxx> Tested-by: Eric DeVolder <eric_devolder@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/arm/include/asm/kexec.h | 4 ---- arch/arm/kernel/Makefile | 2 +- kernel/Kconfig.kexec | 1 - 3 files changed, 1 insertion(+), 6 deletions(-) --- a/arch/arm/include/asm/kexec.h~kernel-kconfigkexec-drop-select-of-kexec-for-crash_dump +++ a/arch/arm/include/asm/kexec.h @@ -2,8 +2,6 @@ #ifndef _ARM_KEXEC_H #define _ARM_KEXEC_H -#ifdef CONFIG_KEXEC - /* Maximum physical address we can use pages from */ #define KEXEC_SOURCE_MEMORY_LIMIT (-1UL) /* Maximum address we can reach in physical address mode */ @@ -82,6 +80,4 @@ static inline struct page *boot_pfn_to_p #endif /* __ASSEMBLY__ */ -#endif /* CONFIG_KEXEC */ - #endif /* _ARM_KEXEC_H */ --- a/arch/arm/kernel/Makefile~kernel-kconfigkexec-drop-select-of-kexec-for-crash_dump +++ a/arch/arm/kernel/Makefile @@ -59,7 +59,7 @@ obj-$(CONFIG_FUNCTION_TRACER) += entry-f obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o insn.o patch.o obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o insn.o patch.o obj-$(CONFIG_JUMP_LABEL) += jump_label.o insn.o patch.o -obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o +obj-$(CONFIG_KEXEC_CORE) += machine_kexec.o relocate_kernel.o # Main staffs in KPROBES are in arch/arm/probes/ . obj-$(CONFIG_KPROBES) += patch.o insn.o obj-$(CONFIG_OABI_COMPAT) += sys_oabi-compat.o --- a/kernel/Kconfig.kexec~kernel-kconfigkexec-drop-select-of-kexec-for-crash_dump +++ a/kernel/Kconfig.kexec @@ -99,7 +99,6 @@ config CRASH_DUMP depends on ARCH_SUPPORTS_KEXEC select CRASH_CORE select KEXEC_CORE - select KEXEC help Generate crash dump after being started by kexec. This should be normally only set in special crash dump kernels _ Patches currently in -mm which might be from bhe@xxxxxxxxxx are drivers-base-cpu-crash-data-showing-should-depends-on-kexec_core.patch kernel-kconfigkexec-drop-select-of-kexec-for-crash_dump.patch resource-add-walk_system_ram_res_rev.patch kexec_file-load-kernel-at-top-of-system-ram-if-required.patch