modprobe: can't load module zstd (kernel/crypto/zstd.ko): unknown symbol in module, or unknown parameter

[frzb]

Booting a focal suite kernel 5.15.0-48-generic with zram bootflag ends up in a kernel panic:

$ qemu-system-x86_64 -kernel coinboot-vmlinuz-5.15.0-48-generic -initrd coinboot-initramfs-5.15.0-48-generic  -m 4096 -smp 2 -nographic  -serial mon:stdio -append "console=ttyS0 net.ifnames=0 biosdevname=0 break=skip_loading_plugins zram"

[...]

Honoring zram kernel arg
[    4.269253] zram: Added device: zram0
[    4.284727] zstd: Unknown symbol ZSTD_initCCtx (err -2)
[    4.285098] zstd: Unknown symbol ZSTD_getParams (err -2)
[    4.285335] zstd: Unknown symbol ZSTD_CCtxWorkspaceBound (err -2)
[    4.285609] zstd: Unknown symbol ZSTD_compressCCtx (err -2)
modprobe: can't load module zstd (kernel/crypto/zstd.ko): unknown symbol in module, or unknown parameter
[    4.360702] Can't allocate a compression stream
[    4.361164] zram: Cannot initialise zstd compressing backend
sh: write error: Cannot allocate memory

[frzb]

When booting with kernel commandline flag break=top to enter an interactive debugging in early user space init we can see that the module zstd_compress.ko is missing. zstd_compress.ko is a depency of the module zstd.ko as we can see with modinfo zstd.

$ qemu-system-x86_64 -kernel coinboot-vmlinuz-5.15.0-48-generic -initrd coinboot-initramfs-5.15.0-48-generic  -m 4096 -smp 2 -nographic  -serial mon:stdio -append "console=ttyS0 net.ifnames=0 biosdevname=0 break=top zram"

[...]

cd /lib/modules/5.15.0-48-generic
/lib/modules/5.15.0-48-generic # ls -R .
.:
kernel

./kernel:
crypto   drivers

./kernel/crypto:
zstd.ko

./kernel/drivers:
block

./kernel/drivers/block:
zram

./kernel/drivers/block/zram:
zram.ko

[frzb]

Did a fix at: 6b6517ef51ec884a9ba31c4bd656e36f1731fc91