Kernel module cross-compile: unrecognized command-line option ‘-mrecord-mcount’

[Michał Fita]

I'm trying to build the external kernel module via cross-compilation for ARM64 on Ubuntu 23.04 and I'm getting following output w/error:

make -C /lib/modules/6.2.0-36-generic/build M=/home/user/Projekty/Opteran/platform_v4l2_driver modules
make[1]: Wejście do katalogu '/usr/src/linux-headers-6.2.0-36-generic'
warning: the compiler differs from the one used to build the kernel
  The kernel was built by: x86_64-linux-gnu-gcc-12 (Ubuntu 12.3.0-1ubuntu1~23.04) 12.3.0
  You are using: aarch64-linux-gnu-gcc-12 (Ubuntu 12.3.0-1ubuntu1~23.04) 12.3.0
  CC [M] /home/user/Projekty/Opteran/platform_v4l2_driver/ova-one.o
aarch64-linux-gnu-gcc-12: error: unrecognized command-line option ‘-mrecord-mcount’
make[2]: *** [scripts/Makefile.build:260: /home/user/Projekty/Opteran/platform_v4l2_driver/ova-one.o] Błąd 1
make[1]: *** [Makefile:2026: /home/user/Projekty/Opteran/platform_v4l2_driver] Błąd 2
make[1]: Opuszczenie katalogu '/usr/src/linux-headers-6.2.0-36-generic'
make: *** [Makefile:9: modules] Błąd 2

The key one being `unrecognized command-line option ‘-mrecord-mcount’`, what - according to Google - was a problem with some old <5 gcc. Why am I facing this today?

My invocation for the build process:

ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make

The `Makefile` I'm using:

obj-m := my-module.o

KERNELDIR ?= /lib/modules/$(shell uname -r)/build

all default: modules
install: modules_install

modules modules_install help clean:
 $(MAKE) -C $(KERNELDIR) M=$(shell pwd) $@