Re: Fwd: [PATCH v4 07/17] kbuild: generate module BTF based on vmlinux.unstripped

[Ihor Solodrai]

On 2/20/26 1:29 AM, Thomas WeiÃschuh wrote:
> Hi BPF/BTF maintainers,
> 
> could you take a look at the patch quoted below?
> It is part of a patch series which only tangentially touches BTF [0].
> If you prefer to receive the full patch series, please let me know and
> I'll do that for the next revision.
> 
> [0] https://lore.kernel.org/lkml/20260113-module-hashes-v4-6-0b932db9b56b@xxxxxxxxxxxxxx/

Hi Thomas, thank you for the ping.

The BTF generation process has significantly changed recently:
https://lore.kernel.org/bpf/20251219181321.1283664-1-ihor.solodrai@xxxxxxxxx/

I suggest you rebase the integrity checking series on top of that
(it's already been merged into Linus' tree).

Adding a .stamp is a small and simple change, so maybe it's worth
landing separately through BPF tree?


> 
> Thomas
> 
> On 2026-01-13 13:28:51+0100, Thomas Weißschuh wrote:
>> The upcoming module hashes functionality will build the modules in
>> between the generation of the BTF data and the final link of vmlinux.
>> At this point vmlinux is not yet built and therefore can't be used for
>> module BTF generation. vmlinux.unstripped however is usable and
>> sufficient for BTF generation.
>>
>> Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
>> ---
>>  scripts/Makefile.modfinal | 8 ++++----
>>  1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
>> index adfef1e002a9..930db0524a0a 100644
>> --- a/scripts/Makefile.modfinal
>> +++ b/scripts/Makefile.modfinal
>> @@ -40,11 +40,11 @@ quiet_cmd_ld_ko_o = LD [M]  $@
>>  
>>  quiet_cmd_btf_ko = BTF [M] $@
>>        cmd_btf_ko = 							\
>> -	if [ ! -f $(objtree)/vmlinux ]; then				\
>> -		printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \
>> +	if [ ! -f $(objtree)/vmlinux.unstripped ]; then			\
>> +		printf "Skipping BTF generation for %s due to unavailability of vmlinux.unstripped\n" $@ 1>&2; \
>>  	else								\
>> -		LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) $(MODULE_PAHOLE_FLAGS) --btf_base $(objtree)/vmlinux $@; \
>> -		$(RESOLVE_BTFIDS) -b $(objtree)/vmlinux $@;		\
>> +		LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) $(MODULE_PAHOLE_FLAGS) --btf_base $(objtree)/vmlinux.unstripped $@; \
>> +		$(RESOLVE_BTFIDS) -b $(objtree)/vmlinux.unstripped $@;	\
>>  	fi;
>>  
>>  # Same as newer-prereqs, but allows to exclude specified extra dependencies
>>
>> -- 
>> 2.52.0
>>