2.2 fails to build kernel modules on aarch64

[q66]

System information

Type	Version/Name
Distribution Name	Chimera Linux
Distribution Version	rolling
Kernel Version	6.5.x
Architecture	aarch64
OpenZFS Version	2:2

Describe the problem you're observing

Does not build on aarch64:

ERROR: modpost: GPL-incompatible module zfs.ko uses GPL-only symbol 'kernel_neon_begin'
ERROR: modpost: GPL-incompatible module zfs.ko uses GPL-only symbol 'kernel_neon_end'

Describe how to reproduce the problem

Build the kernel modules on aarch64.

Include any warning/errors/backtraces from the system logs

Clang 16 compiler, but should not be relevant.

[q66]

Hm, I guess this is actually a dupe of #14555. 2.1.x builds for me because I was patching out the neon paths for raidz/fletcher, but it seems 2.2 brought changes that expand the usage of kernel NEON further, which resulted in that no longer being sufficient.

[luckylinux]

I'm facing the same issue. Kernel 6.6.1 arm64 with ZFS 2.2.1 (since OpenZFS 2.2.1 Linux Kernel 6.6 series is supported).

 make -s -j$(nproc)

  GEN      gitrev
Making all in include
Making all in tests/zfs-tests/tests
  GEN      functional/pyzfs/pyzfs_unittest.ksh
  GEN      functional/pam/utilities.kshlib
Making all in module
warning: the compiler differs from the one used to build the kernel
  The kernel was built by: gcc-13 (Debian 13.2.0-5) 13.2.0
  You are using:           gcc (Debian 12.2.0-14) 12.2.0
ERROR: modpost: GPL-incompatible module zfs.ko uses GPL-only symbol 'kernel_neon_end'
ERROR: modpost: GPL-incompatible module zfs.ko uses GPL-only symbol 'kernel_neon_begin'
make[5]: *** [scripts/Makefile.modpost:145: /usr/src/zfs/zfs-zfs-2.2.1/module/Module.symvers] Error 1
make[4]: *** [/usr/src/linux-headers-6.6.1-1-arm64/Makefile:1865: modpost] Error 2
make[3]: *** [Makefile:234: __sub-make] Error 2
make[2]: *** [Makefile:56: modules-Linux] Error 2
make[1]: *** [Makefile:12116: all-recursive] Error 1
make: *** [Makefile:4600: all] Error 2

The warning is due to using a binary Kernel built from another developer for Rock Pi 5B (on Debian Testing / GCC 13), while I'm on Debian Bookworm / GCC 12.

Any solution for this ?

[q66]

a workaround is https://github.com/chimera-linux/cports/blob/master/main/zfs/patches/aarch64-disable-neon.patch - but that will of course disable all the aarch64 simd

[luckylinux]

Do you mean SIMD as an ARM64 Instruction Set ? What consequences would that have ? Would ZFS work correctly in the end for e.g. a simple Disk / mirror VDEV ?

[q66]

everything will work, some things will miss acceleration

[luckylinux]

Alright, at least it built now. I'll try to see if I can generate the required DEB files and see how it works. Thanks :)