reproduce (this is a W=1 build):
        git checkout f83ec76bf285bea5727f478a68b894f5543ca76e
        b4 shazam https://lore.kernel.org/r/20250915-printk_legacy_thread_console_lock-v1-2-f34d42a9bcb3@thegoodpenguin.co.uk
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=s390 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash kernel/printk/