+CC: Nathan On Sat, May 11, 2024 at 8:18 PM Bagas Sanjaya <bagasdotme@xxxxxxxxx> wrote: > > Hi, > > Xu Zhen <xuzhen@xxxxxxxxxxxx> reported on Bugzilla (https://bugzilla.kernel.org/show_bug.cgi?id=218825) thinlto build directory problem (especially on > DKMS modules). He wrote: > > > In Makefile, the ld flag `--thinlto-cache-dir' is set to > > `$(extmod_prefix).thinlto-cache'. But at that time, the variable extmod_prefix > > had not been assigned yet. Therefore, the thinlto cache dir is always created > > in the current directory. > > > > Even worse, the cache dir cannot be deleted when executing `make clean'. This > > is because its path was written as `$(KBUILD_EXTMOD)/.thinlto-cache' in the > > clean: target. > > > > Some users have been troubled by it: https://github.com/dell/dkms/issues/292 > > > > This bug was introduced by commit dc5723b02e523b2c4a68667f7e28c65018f7202f I agree this is a bug. line 945: KBUILD_LDFLAGS += --thinlto-cache-dir=$(extmod_prefix).thinlto-cache line 1034: KBUILD_LDFLAGS += $(call ld-option,--no-warn-rwx-segments) line 1095: export extmod_prefix = $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/) $(call ld-option ) at line 1034 adds --thinlto-cache-dir=.thinlto-cache because --thinlto-cache-dir=$(extmod_prefix).thinlto-cache was added at line 945, but $(extmod_prefix) is empty until it is defined at line 1095. However, the offending line was already removed for another issue. See the following in linux-next: Author: Nathan Chancellor <nathan@xxxxxxxxxx> Date: Wed May 1 15:55:25 2024 -0700 kbuild: Remove support for Clang's ThinLTO caching If --thinlto-cache-dir comes back, I hope Nathan will take care of this issue. > Thanks. > > -- > An old man doll... just what I always wanted! - Clara -- Best Regards Masahiro Yamada
