On 2024-12-12 15:27:12-0800, Andrii Nakryiko wrote: > On Thu, Dec 12, 2024 at 3:00 PM Thomas Weißschuh <linux@xxxxxxxxxxxxxx> wrote: > > > > These BTF functions are not available unconditionally, > > only reference them when they are available. > > > > Avoid the following build warnings: > > > > BTF .tmp_vmlinux1.btf.o > > btf_encoder__tag_kfunc: failed to find kfunc 'bpf_send_signal_task' in BTF > > btf_encoder__tag_kfuncs: failed to tag kfunc 'bpf_send_signal_task' > > NM .tmp_vmlinux1.syms > > KSYMS .tmp_vmlinux1.kallsyms.S > > AS .tmp_vmlinux1.kallsyms.o > > LD .tmp_vmlinux2 > > NM .tmp_vmlinux2.syms > > KSYMS .tmp_vmlinux2.kallsyms.S > > AS .tmp_vmlinux2.kallsyms.o > > LD vmlinux > > BTFIDS vmlinux > > WARN: resolve_btfids: unresolved symbol prog_test_ref_kfunc > > WARN: resolve_btfids: unresolved symbol bpf_crypto_ctx > > WARN: resolve_btfids: unresolved symbol bpf_send_signal_task > > WARN: resolve_btfids: unresolved symbol bpf_modify_return_test_tp > > WARN: resolve_btfids: unresolved symbol bpf_dynptr_from_xdp > > WARN: resolve_btfids: unresolved symbol bpf_dynptr_from_skb > > > > Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx> > > --- > > kernel/bpf/helpers.c | 4 ++++ > > kernel/bpf/verifier.c | 8 ++++++++ > > 2 files changed, 12 insertions(+) > > > > diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c > > index 751c150f9e1cd7f56e6a2b68a7ebb4ae89a30d2d..5edf5436a7804816b7dcf1bbef2624d71a985f20 100644 > > --- a/kernel/bpf/helpers.c > > +++ b/kernel/bpf/helpers.c > > @@ -3089,7 +3089,9 @@ BTF_ID_FLAGS(func, bpf_task_get_cgroup1, KF_ACQUIRE | KF_RCU | KF_RET_NULL) > > BTF_ID_FLAGS(func, bpf_task_from_pid, KF_ACQUIRE | KF_RET_NULL) > > BTF_ID_FLAGS(func, bpf_task_from_vpid, KF_ACQUIRE | KF_RET_NULL) > > BTF_ID_FLAGS(func, bpf_throw) > > +#ifdef CONFIG_BPF_EVENTS > > BTF_ID_FLAGS(func, bpf_send_signal_task, KF_TRUSTED_ARGS) > > +#endif > > BTF_KFUNCS_END(generic_btf_ids) > > > > static const struct btf_kfunc_id_set generic_kfunc_set = { > > @@ -3135,7 +3137,9 @@ BTF_ID_FLAGS(func, bpf_dynptr_is_null) > > BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly) > > BTF_ID_FLAGS(func, bpf_dynptr_size) > > BTF_ID_FLAGS(func, bpf_dynptr_clone) > > +#ifdef CONFIG_NET > > BTF_ID_FLAGS(func, bpf_modify_return_test_tp) > > +#endif > > It makes little sense to have bpf_prog_test_run_tracing() and > bpf_modify_return_test_tp() depend on CONFIG_NET... It's just > historically where BPF_PROG_TEST_RUN functionality was implemented, > but it seems like we need to move bpf_prog_test_run_tracing() and > other tracing-related testing stuff into kernel/trace/bpf_trace.c or > somewhere under kernel/bpf/ (core.c? helpers.c?) I agree. But today these are the config values which are in effect. When the functions get moved, the config values can be adapted. With my commit "kbuild/btf: Propagate CONFIG_WERROR to resolve_btfids" in bpf-next the warnings can actually become errors. So I'd propose to apply this fix to avoid issues in the near future and then do a proper move without any urgency. > > BTF_ID_FLAGS(func, bpf_wq_init) > > BTF_ID_FLAGS(func, bpf_wq_set_callback_impl) > > BTF_ID_FLAGS(func, bpf_wq_start) > > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > > index 5e541339b2f6d1870561033fd55cca7144db14bc..77bbf58418fee7533bce539c8e005d2342ee1a48 100644 > > --- a/kernel/bpf/verifier.c > > +++ b/kernel/bpf/verifier.c > > @@ -5526,7 +5526,9 @@ static bool in_rcu_cs(struct bpf_verifier_env *env) > > > > /* Once GCC supports btf_type_tag the following mechanism will be replaced with tag check */ > > BTF_SET_START(rcu_protected_types) > > +#ifdef CONFIG_NET > > BTF_ID(struct, prog_test_ref_kfunc) > > +#endif > > #ifdef CONFIG_CGROUPS > > BTF_ID(struct, cgroup) > > #endif > > @@ -5534,7 +5536,9 @@ BTF_ID(struct, cgroup) > > BTF_ID(struct, bpf_cpumask) > > #endif > > BTF_ID(struct, task_struct) > > +#ifdef CONFIG_CRYPTO > > BTF_ID(struct, bpf_crypto_ctx) > > +#endif > > BTF_SET_END(rcu_protected_types) > > > > static bool rcu_protected_object(const struct btf *btf, u32 btf_id) > > @@ -11529,8 +11533,10 @@ BTF_ID(func, bpf_rdonly_cast) > > BTF_ID(func, bpf_rbtree_remove) > > BTF_ID(func, bpf_rbtree_add_impl) > > BTF_ID(func, bpf_rbtree_first) > > +#ifdef CONFIG_NET > > BTF_ID(func, bpf_dynptr_from_skb) > > BTF_ID(func, bpf_dynptr_from_xdp) > > +#endif > > BTF_ID(func, bpf_dynptr_slice) > > BTF_ID(func, bpf_dynptr_slice_rdwr) > > BTF_ID(func, bpf_dynptr_clone) > > @@ -11558,8 +11564,10 @@ BTF_ID(func, bpf_rcu_read_unlock) > > BTF_ID(func, bpf_rbtree_remove) > > BTF_ID(func, bpf_rbtree_add_impl) > > BTF_ID(func, bpf_rbtree_first) > > +#ifdef CONFIG_NET > > BTF_ID(func, bpf_dynptr_from_skb) > > BTF_ID(func, bpf_dynptr_from_xdp) > > +#endif > > BTF_ID(func, bpf_dynptr_slice) > > BTF_ID(func, bpf_dynptr_slice_rdwr) > > BTF_ID(func, bpf_dynptr_clone) > > > > --- > > base-commit: 5d287a7de3c95b78946e71d17d15ec9c87fffe7f > > change-id: 20241212-bpf-cond-ids-9bfbc64dd77b > > > > Best regards, > > -- > > Thomas Weißschuh <linux@xxxxxxxxxxxxxx> > >