exfat driver not compiling on rpi4

[KacperSynator]

The dkms exfat-nofuse is not compiling on RPI4.

I run the crankshaft systemcheck and the output was:

Crankshaft Management Tool v2.4.0 is executing command...

Checking systemd automount flag:

CSMT has detected a wrong setup in systemd for usb drives!
Applying fix for it...
Reboot your system to activate the fix!

Checking dkms exfat module:

CSMT has detected mising exfat module!
Trying to rebuild it...

Kernel preparation unnecessary for this kernel.  Skipping...

Building module:
cleaning build area...
KDIR=/lib/modules/5.10.103-v7l+/build MDIR=/lib/modules/5.10.103-v7l+ make.....(bad exit status: 2)
Error! Bad return status for module build on kernel: 5.10.103-v7l+ (armv7l)
Consult /var/lib/dkms/exfat/1.2.8/build/make.log for more information.
Module build failed.


All checks done.

Done.

The log file:

cat  /var/lib/dkms/exfat/1.2.8/build/make.log
DKMS make.log for exfat-1.2.8 for kernel 5.10.103-v7l+ (armv7l)
Sun Sep 11 23:58:57 CEST 2022
make -C /lib/modules/5.10.103-v7l+/build M=/var/lib/dkms/exfat/1.2.8/build modules
make[1]: Entering directory '/usr/src/linux-headers-5.10.103-v7l+'
  CC [M]  /var/lib/dkms/exfat/1.2.8/build/exfat_core.o
  CC [M]  /var/lib/dkms/exfat/1.2.8/build/exfat_super.o
/var/lib/dkms/exfat/1.2.8/build/exfat_super.c: In function ‘exfat_readpages’:
/var/lib/dkms/exfat/1.2.8/build/exfat_super.c:1635:9: error: implicit declaration of function ‘mpage_readpages’; did you mean ‘mpage_readpage’? [-Werror=implicit-function-declaration]
  ret =  mpage_readpages(mapping, pages, nr_pages, exfat_get_block);
         ^~~~~~~~~~~~~~~
         mpage_readpage
cc1: some warnings being treated as errors
make[2]: *** [scripts/Makefile.build:280: /var/lib/dkms/exfat/1.2.8/build/exfat_super.o] Error 1
make[1]: *** [Makefile:1825: /var/lib/dkms/exfat/1.2.8/build] Error 2
make[1]: Leaving directory '/usr/src/linux-headers-5.10.103-v7l+'
make: *** [Makefile:35: all] Error 2

I did a small research and some functions are not supported in newer kernel versions: barrybingo/exfat-nofuse#5.
The exfat-nofuse repo which it is build from, contains a branch with fixes for newer kernel versions: https://github.com/barrybingo/exfat-nofuse/tree/new-kernel-patches. So i changed this line

crankshaft/stage3/03-crankshaft-base/02-run-chroot.sh

Line 282 in e43c74e

git merge barrybingo/master

to point the new-kernel-patches branch instead of master and build the image. But the dkms is still not building properly:

cat /var/lib/dkms/exfat/1.2.8/build/make.log
DKMS make.log for exfat-1.2.8 for kernel 5.10.103-v7l+ (armv7l)
Sun 23 Feb 11:40:09 UTC 2025
make -C /lib/modules/5.10.103-v7l+/build M=/var/lib/dkms/exfat/1.2.8/build modules
make[1]: Entering directory '/usr/src/linux-headers-5.10.103-v7l+'
  CC [M]  /var/lib/dkms/exfat/1.2.8/build/exfat_core.o
  CC [M]  /var/lib/dkms/exfat/1.2.8/build/exfat_super.o
  CC [M]  /var/lib/dkms/exfat/1.2.8/build/exfat_api.o
  CC [M]  /var/lib/dkms/exfat/1.2.8/build/exfat_blkdev.o
  CC [M]  /var/lib/dkms/exfat/1.2.8/build/exfat_cache.o
  CC [M]  /var/lib/dkms/exfat/1.2.8/build/exfat_data.o
  CC [M]  /var/lib/dkms/exfat/1.2.8/build/exfat_bitmap.o
  CC [M]  /var/lib/dkms/exfat/1.2.8/build/exfat_nls.o
  CC [M]  /var/lib/dkms/exfat/1.2.8/build/exfat_oal.o
  CC [M]  /var/lib/dkms/exfat/1.2.8/build/exfat_upcase.o
  LD [M]  /var/lib/dkms/exfat/1.2.8/build/exfat.o
  MODPOST /var/lib/dkms/exfat/1.2.8/build/Module.symvers
ERROR: modpost: "__aeabi_ldivmod" [/var/lib/dkms/exfat/1.2.8/build/exfat.ko] undefined!
ERROR: modpost: "__aeabi_uldivmod" [/var/lib/dkms/exfat/1.2.8/build/exfat.ko] undefined!
make[2]: *** [scripts/Makefile.modpost:124: /var/lib/dkms/exfat/1.2.8/build/Module.symvers] Error 1
make[2]: *** Deleting file '/var/lib/dkms/exfat/1.2.8/build/Module.symvers'
make[1]: *** [Makefile:1729: modules] Error 2
make[1]: Leaving directory '/usr/src/linux-headers-5.10.103-v7l+'
make: *** [Makefile:35: all] Error 2