Hi!

When updating the Alpine Linux kernel to 6.6.70 I bumped into a new compile error:

LD .tmp_vmlinux.kallsyms1 ld: vmlinux.o: in function `__crash_kexec': /home/ncopa/aports/main/linux-lts/src/linux-6.6/kernel/kexec_core.c:1075:(.text+0x1bffd0): undefined reference to `machine_crash_shutdown' ld: vmlinux.o: in function `do_kexec_load': /home/ncopa/aports/main/linux-lts/src/linux-6.6/kernel/kexec.c:166:(.text+0x1c1b4e): undefined reference to `arch_kexec_protect_crashkres' ld: /home/ncopa/aports/main/linux-lts/src/linux-6.6/kernel/kexec.c:105:(.text+0x1c1b94): undefined reference to `arch_kexec_unprotect_crashkres' make[2]: *** [/home/ncopa/aports/main/linux-lts/src/linux-6.6/scripts/Makefile.vmlinux:37: vmlinux] Error 1 make[1]: *** [/home/ncopa/aports/main/linux-lts/src/linux-6.6/Makefile:1164: vmlinux] Error 2 make: *** [/home/ncopa/aports/main/linux-lts/src/linux-6.6/Makefile:234: __sub-make] Error 2

$ grep -E '(CRASH_CORE|_KEXEC)' .config CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_KEXEC=y # CONFIG_KEXEC_FILE is not set # CONFIG_KEXEC_JUMP is not set CONFIG_ARCH_SUPPORTS_KEXEC=y CONFIG_ARCH_SUPPORTS_KEXEC_FILE=y CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY=y CONFIG_ARCH_SUPPORTS_KEXEC_SIG=y CONFIG_ARCH_SUPPORTS_KEXEC_SIG_FORCE=y CONFIG_ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG=y CONFIG_ARCH_SUPPORTS_KEXEC_JUMP=y

Looking at the git history I notice this commit:

From e5b1574a8ca28c40cf53eda43f6c3b016ed41e27 Mon Sep 17 00:00:00 2001 From: Baoquan He bhe@redhat.com Date: Wed, 24 Jan 2024 13:12:46 +0800 Subject: x86, crash: wrap crash dumping code into crash related ifdefs

[ Upstream commit a4eeb2176d89fdf2785851521577b94b31690a60 ]

Now crash codes under kernel/ folder has been split out from kexec code, crash dumping can be separated from kexec reboot in config items on x86 with some adjustments.

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=l...

So a wild guess is that the commit(s) that splits out crash codes under kernel/ directory from kexec code also needs to be backported to linux-6.6.y?

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=l...

Thanks!

-nc