Please build linux kernel with CONFIG_MODULE_COMPRESS_ZSTD

Is this a new report?

Yes

System Info

Void 7.0.0-30-generic x86_64 GenuineIntel notuptodate r

Package(s) Affected

linux-6.18_1 linux6.18-6.18.48_1

Does a report exist for this bug with the project's home (upstream) and/or another distro?

No response

Expected behaviour

Loading kernel modules with busybox's modprobe should work.

Please build linux kernel with CONFIG_MODULE_COMPRESS_ZSTD to let the kernel read the zstd compressed kernel modules.

# grep ZST /boot/config-6.18.48_1 
CONFIG_HAVE_KERNEL_ZSTD=y
# CONFIG_KERNEL_ZSTD is not set
CONFIG_RD_ZSTD=y
# CONFIG_MODULE_COMPRESS_ZSTD is not set
# CONFIG_ZSWAP_COMPRESSOR_DEFAULT_ZSTD is not set
CONFIG_FW_LOADER_COMPRESS_ZSTD=y
CONFIG_ZRAM_BACKEND_ZSTD=y
# CONFIG_ZRAM_DEF_COMP_ZSTD is not set
CONFIG_F2FS_FS_ZSTD=y
CONFIG_SQUASHFS_ZSTD=y
# CONFIG_EROFS_FS_ZIP_ZSTD is not set
CONFIG_CRYPTO_ZSTD=y
CONFIG_ZSTD_COMMON=y
CONFIG_ZSTD_COMPRESS=y
CONFIG_ZSTD_DECOMPRESS=y
CONFIG_DECOMPRESS_ZSTD=y
# CONFIG_DEBUG_INFO_COMPRESSED_ZSTD is not set

Actual behaviour

Loading kernel modules with busybox's modprobe fails because modprobe does not have zstd support:

# busybox modprobe ext4
[    7.470059] Invalid ELF header magic: != ELF
[    7.470729] Invalid ELF header magic: != ELF
modprobe: 'kernel/fs/ext4/ext4.ko.zst': invalid module format

Steps to reproduce

Run the busybox test on void: https://github.com/dracut-ng/dracut/pull/2697

test/test.sh void:latest 15

Start with the linux-6.18_1 and linux6.18-6.18.48_1 package configuration, comparing it with /boot/config-6.18.48_1 and the requested CONFIG_MODULE_COMPRESS_ZSTD setting. Run test/test.sh void:latest 15, and consider the work done when BusyBox modprobe can load the zstd-compressed ext4 module without an invalid module format error.