Hi Eduard, On 04/10/2025 01:37, Eduard Zingerman wrote: > On Fri, 2025-10-03 at 17:24 +0200, Matthieu Baerts (NGI0) wrote: >> When trying to build the latest BPF selftests, with a debug kernel >> config, Pahole 1.30 and CLang 20.1.8 (and GCC 15.2), I got these errors: >> >> progs/dynptr_success.c:579:9: error: call to undeclared function >> 'bpf_dynptr_slice'; ISO C99 and later do not support implicit function >> declarations [-Wimplicit-function-declaration] >> 579 | data = bpf_dynptr_slice(&ptr, 0, NULL, 1); >> | ^ >> progs/dynptr_success.c:579:9: note: did you mean 'bpf_dynptr_size'? >> .virtme/build-debug-btf//tools/include/vmlinux.h:120280:14: note: >> 'bpf_dynptr_size' declared here >> 120280 | extern __u32 bpf_dynptr_size(const struct bpf_dynptr *p) __weak >> __ksym; >> | ^ >> progs/dynptr_success.c:579:7: error: incompatible integer to pointer >> conversion assigning to '__u64 *' (aka 'unsigned long long *') from 'int' >> [-Wint-conversion] >> 579 | data = bpf_dynptr_slice(&ptr, 0, NULL, 1); >> | ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> progs/dynptr_success.c:596:9: error: call to undeclared function >> 'bpf_dynptr_slice'; ISO C99 and later do not support implicit function >> declarations [-Wimplicit-function-declaration] >> 596 | data = bpf_dynptr_slice(&ptr, 0, NULL, 10); >> | ^ >> progs/dynptr_success.c:596:7: error: incompatible integer to pointer >> conversion assigning to 'char *' from 'int' [-Wint-conversion] >> 596 | data = bpf_dynptr_slice(&ptr, 0, NULL, 10); >> | ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> >> I don't have these errors without the debug kernel config from >> kernel/configs/debug.config. With the debug kernel, bpf_dynptr_slice() >> is not declared in vmlinux.h. It is declared there without debug.config. >> >> The fix is similar to what is done in dynptr_fail.c which is also using >> bpf_dynptr_slice(): bpf_kfuncs.h is now included. >> >> Signed-off-by: Matthieu Baerts (NGI0) <[email protected]> >> --- > > I can reproduce similar issue when including > kernel/configs/debug.config with my regular dev config, but for > different functions: bpf_rcu_read_{un,}lock().
Thank you for having checked! I also had issues with these functions on my side, when testing on top of 'net'. > However, this is not a way to fix this. > Kfuncs are not supposed to just disappear from DWARF. Indeed. But strange it was fine before. Or fine without debug.config. Cheers, Matt -- Sponsored by the NGI0 Core fund.
