Zfs 2.3.5 failed to build module in kernel for Fedora

[vuongtuha]

I just upgrade version from 42 to 43. Old kernel 6.17.9-cachyos1.lto.fc42.x86_64 used to work fine and is still running after upgrade process. But I cannot build zfs kernel module for these kernel line
Here's is failed log:

DKMS (dkms-3.3.0) make.log for zfs/2.3.5 for kernel 6.17.9-cachyos1.lto.fc43.x86_64 (x86_64)
Sun 30 Nov 09:51:03 +07 2025

Running the pre_build script
# command: cd /var/lib/dkms/zfs/2.3.5/build/ && /var/lib/dkms/zfs/2.3.5/build/configure --disable-dependency-tracking --prefix=/usr --with-config=kernel --with-linux=/lib/modules/6.17.9-cachyos1.lto.fc43.x86_64/source --with-linux-obj=/lib/modules/6.17.9-cachyos1.lto.fc43.x86_64/build --with-qat= 
configure: loading site script /usr/share/config.site
checking for gawk... gawk
checking metadata... META file
checking build system type... x86_64-pc-linux-gnu
checking host system type... x86_64-pc-linux-gnu
checking target system type... x86_64-pc-linux-gnu
checking whether to enable maintainer-specific portions of Makefiles... no
checking whether make supports nested variables... yes
checking for a BSD-compatible install... /usr/bin/install -c
checking whether sleep supports fractional seconds... yes
checking filesystem timestamp resolution... 0.01
checking whether build environment is sane... yes
checking for a race-free mkdir -p... /usr/sbin/mkdir -p
checking whether make sets $(MAKE)... yes
checking xargs -n works... yes
checking whether UID '0' is supported by ustar format... yes
checking whether GID '0' is supported by ustar format... yes
checking how to create a ustar tar archive... gnutar
checking how to print strings... printf
checking whether make supports the include directive... yes (GNU style)
checking for gcc... clang
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
checking for suffix of executables... 
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether the compiler supports GNU C... yes
checking whether clang accepts -g... yes
checking for clang option to enable C11 features... none needed
checking whether clang understands -c and -o together... yes
checking dependency style of clang... none
checking for a sed that does not truncate output... /usr/sbin/sed
checking for grep that handles long lines and -e... /usr/sbin/grep
checking for egrep... /usr/sbin/grep -E
checking for fgrep... /usr/sbin/grep -F
checking for ld used by clang... ld.lld
checking if the linker (ld.lld) is GNU ld... yes
checking for BSD- or MS-compatible name lister (nm)... /usr/sbin/nm -B
checking the name lister (/usr/sbin/nm -B) interface... BSD nm
checking whether ln -s works... yes
checking the maximum length of command line arguments... 1572864
checking how to convert x86_64-pc-linux-gnu file names to x86_64-pc-linux-gnu format... func_convert_file_noop
checking how to convert x86_64-pc-linux-gnu file names to toolchain format... func_convert_file_noop
checking for ld.lld option to reload object files... -r
checking for file... file
checking for objdump... objdump
checking how to recognize dependent libraries... pass_all
checking for dlltool... no
checking how to associate runtime and link libraries... printf %s\n
checking for ranlib... ranlib
checking for ar... ar
checking for archiver @FILE support... @
checking for strip... strip
checking command to parse /usr/sbin/nm -B output from clang object... ok
checking for sysroot... no
checking for a working dd... /usr/sbin/dd
checking how to truncate binary pipes... /usr/sbin/dd bs=4096 count=1
checking for mt... no
checking if : is a manifest tool... no
checking for stdio.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for strings.h... yes
checking for sys/stat.h... yes
checking for sys/types.h... yes
checking for unistd.h... yes
checking for dlfcn.h... yes
checking for objdir... .libs
checking if clang supports -fno-rtti -fno-exceptions... yes
checking for clang option to produce PIC... -fPIC -DPIC
checking if clang PIC flag -fPIC -DPIC works... yes
checking if clang static flag -static works... no
checking if clang supports -c -o file.o... yes
checking if clang supports -c -o file.o... (cached) yes
checking whether the clang linker (ld.lld -m elf_x86_64) supports shared libraries... yes
checking whether -lc should be explicitly linked in... no
checking dynamic linker characteristics... GNU/Linux ld.so
checking how to hardcode library paths into programs... immediate
checking whether stripping libraries is possible... yes
checking if libtool supports shared libraries... yes
checking whether to build shared libraries... yes
checking whether to build static libraries... yes
checking for gcc... (cached) clang
checking whether the compiler supports GNU C... (cached) yes
checking whether clang accepts -g... (cached) yes
checking for clang option to enable C11 features... (cached) none needed
checking whether clang understands -c and -o together... (cached) yes
checking dependency style of clang... (cached) none
checking whether ln -s works... yes
checking for pkg-config... /usr/sbin/pkg-config
checking pkg-config is at least version 0.9.0... yes
checking dependency style of clang... none
checking whether to build with code coverage support... no
checking how to create a pax tar archive... gnutar
checking zfs author... OpenZFS
checking zfs license... CDDL
checking whether NLS is requested... yes
checking for msgfmt... /usr/sbin/msgfmt
checking for gmsgfmt... /usr/sbin/msgfmt
checking for xgettext... /usr/sbin/xgettext
checking for msgmerge... /usr/sbin/msgmerge
checking for ld... ld.lld -m elf_x86_64
checking if the linker (ld.lld -m elf_x86_64) is GNU ld... yes
checking for shared library run path origin... done
checking 32-bit host C ABI... no
checking how to run the C preprocessor... clang -E
checking for egrep -e... (cached) /usr/sbin/grep -E
checking for ELF binary format... yes
checking for the common suffixes of directories in the library search path... lib,lib,lib64
checking zfs config... kernel
checking the number of available CPUs... 24
checking whether clang supports -Wno-clobbered... no
checking whether clang supports -Winfinite-recursion... yes
checking whether clang supports -Winfinite-recursion... yes
checking whether clang supports -Wimplicit-fallthrough... yes
checking whether clang supports -Wframe-larger-than=<size>... yes
checking whether clang supports -Wno-format-truncation... yes
checking whether clang supports -Wno-format-zero-length... yes
checking whether clang supports -Wformat-overflow... yes
checking whether clang supports -fno-omit-frame-pointer... yes
checking whether clang supports -fno-ipa-sra... no
checking whether clang supports -fno-ipa-sra... no
checking whether to build with -fsanitize=address support... no
checking whether to build with -fsanitize=undefined support... no
checking whether host toolchain supports SSE... yes
checking whether host toolchain supports SSE2... yes
checking whether host toolchain supports SSE3... yes
checking whether host toolchain supports SSSE3... yes
checking whether host toolchain supports SSE4.1... yes
checking whether host toolchain supports SSE4.2... yes
checking whether host toolchain supports AVX... yes
checking whether host toolchain supports AVX2... yes
checking whether host toolchain supports AVX512F... yes
checking whether host toolchain supports AVX512CD... yes
checking whether host toolchain supports AVX512DQ... yes
checking whether host toolchain supports AVX512BW... yes
checking whether host toolchain supports AVX512IFMA... yes
checking whether host toolchain supports AVX512VBMI... yes
checking whether host toolchain supports AVX512PF... yes
checking whether host toolchain supports AVX512ER... yes
checking whether host toolchain supports AVX512VL... yes
checking whether host toolchain supports AES... yes
checking whether host toolchain supports PCLMULQDQ... yes
checking whether host toolchain supports MOVBE... yes
checking whether host toolchain supports XSAVE... yes
checking whether host toolchain supports XSAVEOPT... yes
checking whether host toolchain supports XSAVES... yes
checking for system type (linux-gnu)... Linux
checking for python3... python3
checking for python version... 3.14
checking for python platform... linux
checking for GNU default python prefix... ${prefix}
checking for GNU default python exec_prefix... ${exec_prefix}
checking for python script directory (pythondir)... ${PYTHON_PREFIX}/lib/python3.14/site-packages
checking for python extension module directory (pyexecdir)... ${PYTHON_EXEC_PREFIX}/lib64/python3.14/site-packages
configure: Disabling pyzfs for kernel/srpm config
checking whether to enable pyzfs: ... no
checking for sed --in-place... --in-place
checking for cppcheck... no
checking for shellcheck... no
checking for checkbashisms... no
checking for parallel... no
checking kernel source and build directories... done
checking kernel source directory... /lib/modules/6.17.9-cachyos1.lto.fc43.x86_64/source
checking kernel build directory... /lib/modules/6.17.9-cachyos1.lto.fc43.x86_64/build
checking kernel source version... 6.17.9-cachyos1.lto.fc43.x86_64
checking for kernel config option compatibility... done
checking whether CONFIG_MODULES is defined... yes
checking whether CONFIG_BLOCK is defined... yes
checking whether mutex_lock() is GPL-only... no
checking whether CONFIG_TRIM_UNUSED_KSYM is disabled... yes
checking whether CONFIG_ZLIB_DEFLATE is defined... yes
checking whether CONFIG_ZLIB_INFLATE is defined... yes
checking kernel file name for module symbols... Module.symvers
checking whether fpu headers are available... asm/fpu/api.h
checking whether objtool header is available... linux/objtool.h
checking whether /dev/zfs minor is available... 249
checking whether DECLARE_EVENT_CLASS() is available... no
checking for available kernel interfaces... done
checking whether kernel defines intptr_t... yes
checking whether access_ok() has 'type' parameter... no
checking whether compile-time stack validation (objtool) is available... yes
checking whether STACK_FRAME_NON_STANDARD is defined... yes
checking whether STACK_FRAME_NON_STANDARD asm macro is defined... yes
checking whether CONFIG_OBJTOOL_WERROR is defined... no
checking whether pde_data() is lowercase... yes
checking whether generic_fadvise() is available... yes
checking whether header linux/sched/rt.h exists... yes
checking whether usleep_range() is available... yes
checking whether __vmalloc(ptr, flags, pageflags) is available... no
checking whether timestamp_truncate() exists... yes
checking whether inode_get_ctime() exists... yes
checking whether inode_set_ctime_to_ts() exists... yes
checking whether inode_get_atime() exists... yes
checking whether inode_set_atime_to_ts() exists... yes
checking whether inode_get_mtime() exists... yes
checking whether inode_set_mtime_to_ts() exists... yes
checking whether proc_ops structure exists... yes
checking whether bops->check_events() exists... yes
checking whether bops->release() is void and takes 2 args... no
checking whether bops->release() is void and takes 1 arg... yes
checking whether bops->revalidate_disk() exists... no
checking whether bio_set_op_attrs is available... no
checking whether bio_set_dev() is GPL-only... yes
checking whether bio_set_dev() is a macro... no
checking whether current->bio_list exists... yes
checking whether blkg_tryget() is available... no
checking whether bio->bi_bdev->bd_disk exists... yes
checking whether block_device_operations->submit_bio() returns void... yes
checking whether bio_alloc() wants 4 args... yes
checking whether blkdev_get_by_path() exists and takes 3 args... no
checking whether blkdev_get_by_path() exists and takes 4 args... no
checking whether bdev_open_by_path() exists... no
checking whether bdev_file_open_by_path() exists... no
configure: error: 
	*** None of the expected "blkdev_get_by_path()" interfaces were detected.
	*** This may be because your kernel version is newer than what is
	*** supported, or you are using a patched custom kernel with
	*** incompatible modifications.
	***
	*** ZFS Version: zfs-2.3.5-1
	*** Compatible Kernels: 4.18 - 6.17
	

# exit code: 1
# elapsed time: 00:01:01
----------------------------------------------------------------

My system enabled secure boot MOK, also UKI packed by dracut. I'm not really sure it's bug on zfs Fedora repo or not, but Nvidia could be rebuilt okay. Reinstall zfs-dkms could not solve itself.
dkms status zfs
zfs/2.3.5, 6.17.8-300.fc43.x86_64, x86_64: installed
Zpool is loaded and running on system that I'm typing now. So situation is still okay. And my truly desire is understand how it failed in background. Log didn't give me much info. Very irony, log show building for kernel 6.17 but failed in this kernel ver.
Here is source kernel:
https://copr.fedorainfracloud.org/coprs/bieszczaders/kernel-cachyos-lto/package/kernel-cachyos-lto/

System information

Type	Version/Name
Distribution Name	Fedora
Distribution Version	43
Kernel Version
Architecture	x86-64
OpenZFS Version	2.3.5-1

Current state:
uname -r 6.17.8-300.fc43.x86_64
cat /etc/*-release Fedora release 43 (Forty Three)
-->

[alex-moch]

You seem to be using Clang. #17684 should fix the issue.

[vuongtuha]

Upper said true, i'm using llvm-21.1.6, clang-21.1.6.
To prove it, I tried the same kernel line (cachyos), same version (6.17.9), only non-LTO. Then it ran finished automatically, auto sign all modules okay.
Now it matters to find out failed interactive layer that zfs-dkms couldn't detect right kernel version. I would expected you backport PR should be in upstream already, isn't it?

[alex-moch]

#17684 is in the master branch but not in the zfs-2.3-release branch. You were not the only one in the issue tracker with this problem.

That's why I created the backport pull request.

[vuongtuha]

Thanks your info very much,
anyway, it's not too serious trouble, then I can keep using GCC kernel normally. And I'm not a fan of patching myself. So I guess my ticket could be closed. Just wait little time to let this PR appear in release version.