diff mbox series

[bpf] bpf: fix configuration-dependent BTF function references

Message ID 20241213-bpf-cond-ids-v1-1-881849997219@weissschuh.net (mailing list archive)
State Superseded
Commit 00a5acdbf39816ad23b8db3255c366bbc77e69af
Delegated to: BPF
Headers show
Series [bpf] bpf: fix configuration-dependent BTF function references | expand

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Commit Message

Thomas Weißschuh Dec. 12, 2024, 11 p.m. UTC 
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@weissschuh.net>
---
 kernel/bpf/helpers.c  | 4 ++++
 kernel/bpf/verifier.c | 8 ++++++++
 2 files changed, 12 insertions(+)


---
base-commit: 5d287a7de3c95b78946e71d17d15ec9c87fffe7f
change-id: 20241212-bpf-cond-ids-9bfbc64dd77b

Best regards,

Comments

Andrii Nakryiko Dec. 12, 2024, 11:27 p.m. UTC | #1 
On Thu, Dec 12, 2024 at 3:00 PM Thomas Weißschuh <linux@weissschuh.net> 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@weissschuh.net>
> ---
>  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?)

>  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@weissschuh.net>
>
Thomas Weißschuh Dec. 12, 2024, 11:37 p.m. UTC | #2 
On 2024-12-12 15:27:12-0800, Andrii Nakryiko wrote:
> On Thu, Dec 12, 2024 at 3:00 PM Thomas Weißschuh <linux@weissschuh.net> 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@weissschuh.net>
> > ---
> >  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@weissschuh.net>
> >
Andrii Nakryiko Dec. 13, 2024, 10:37 p.m. UTC | #3 
On Thu, Dec 12, 2024 at 3:37 PM Thomas Weißschuh <linux@weissschuh.net> wrote:
>
> On 2024-12-12 15:27:12-0800, Andrii Nakryiko wrote:
> > On Thu, Dec 12, 2024 at 3:00 PM Thomas Weißschuh <linux@weissschuh.net> 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@weissschuh.net>
> > > ---
> > >  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.
>

Fair enough.

Acked-by: Andrii Nakryiko <andrii@kernel.org>

> > >  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@weissschuh.net>
> > >
patchwork-bot+netdevbpf@kernel.org Dec. 13, 2024, 11:10 p.m. UTC | #4 
Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Fri, 13 Dec 2024 00:00:30 +0100 you 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
> 
> [...]

Here is the summary with links:
  - [bpf] bpf: fix configuration-dependent BTF function references
    https://git.kernel.org/bpf/bpf-next/c/00a5acdbf398

You are awesome, thank you!
Alexei Starovoitov Dec. 18, 2024, 9:18 p.m. UTC | #5 
On Fri, Dec 13, 2024 at 3:10 PM <patchwork-bot+netdevbpf@kernel.org> wrote:
>
> Hello:
>
> This patch was applied to bpf/bpf-next.git (master)
> by Andrii Nakryiko <andrii@kernel.org>:
>
> On Fri, 13 Dec 2024 00:00:30 +0100 you 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
> >
> > [...]
>
> Here is the summary with links:
>   - [bpf] bpf: fix configuration-dependent BTF function references
>     https://git.kernel.org/bpf/bpf-next/c/00a5acdbf398

Just noticed that this is broken.
The #ifdef CONFIG_NET part in special_kfunc_list()
needs to match positions in enum special_kfunc_type.
BTF_ID_UNUSED must be used when !CONFIG_NET.

Pls send the fix.
diff mbox series

Patch

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
 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)