diff mbox series

[RFCv2,bpf-next,2/4] bpf: Add bpf_kprobe_multi_is_return kfunc

Message ID 20240228090242.4040210-3-jolsa@kernel.org (mailing list archive)
State RFC
Delegated to: BPF
Headers show
Series bpf: Introduce kprobe multi wrapper attach | expand

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Commit Message

Jiri Olsa Feb. 28, 2024, 9:02 a.m. UTC 
Adding bpf_kprobe_multi_is_return kfunc that returns true if the
bpf program is executed from the exit probe of the kprobe multi
link attached in wrapper mode. It returns false otherwise.

Adding new kprobe hook for kprobe program type.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 kernel/bpf/btf.c         |  3 +++
 kernel/trace/bpf_trace.c | 49 +++++++++++++++++++++++++++++++++++++---
 2 files changed, 49 insertions(+), 3 deletions(-)

Comments

Andrii Nakryiko Feb. 29, 2024, 1:23 a.m. UTC | #1 
On Wed, Feb 28, 2024 at 1:03 AM Jiri Olsa <jolsa@kernel.org> wrote:
>
> Adding bpf_kprobe_multi_is_return kfunc that returns true if the
> bpf program is executed from the exit probe of the kprobe multi
> link attached in wrapper mode. It returns false otherwise.
>
> Adding new kprobe hook for kprobe program type.
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  kernel/bpf/btf.c         |  3 +++
>  kernel/trace/bpf_trace.c | 49 +++++++++++++++++++++++++++++++++++++---
>  2 files changed, 49 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> index 6ff0bd1a91d5..5ab55720e881 100644
> --- a/kernel/bpf/btf.c
> +++ b/kernel/bpf/btf.c
> @@ -218,6 +218,7 @@ enum btf_kfunc_hook {
>         BTF_KFUNC_HOOK_SOCKET_FILTER,
>         BTF_KFUNC_HOOK_LWT,
>         BTF_KFUNC_HOOK_NETFILTER,
> +       BTF_KFUNC_HOOK_KPROBE,
>         BTF_KFUNC_HOOK_MAX,
>  };
>
> @@ -8112,6 +8113,8 @@ static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
>                 return BTF_KFUNC_HOOK_LWT;
>         case BPF_PROG_TYPE_NETFILTER:
>                 return BTF_KFUNC_HOOK_NETFILTER;
> +       case BPF_PROG_TYPE_KPROBE:
> +               return BTF_KFUNC_HOOK_KPROBE;
>         default:
>                 return BTF_KFUNC_HOOK_MAX;
>         }
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 726a8c71f0da..cb801c94b8fa 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -2594,6 +2594,7 @@ struct bpf_kprobe_multi_run_ctx {
>         struct bpf_run_ctx run_ctx;
>         struct bpf_kprobe_multi_link *link;
>         unsigned long entry_ip;
> +       bool is_return;
>  };
>
>  struct user_syms {
> @@ -2793,11 +2794,13 @@ static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx)
>
>  static int
>  kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
> -                          unsigned long entry_ip, struct pt_regs *regs)
> +                          unsigned long entry_ip, struct pt_regs *regs,
> +                          bool is_return)
>  {
>         struct bpf_kprobe_multi_run_ctx run_ctx = {
>                 .link = link,
>                 .entry_ip = entry_ip,
> +               .is_return = is_return,
>         };
>         struct bpf_run_ctx *old_run_ctx;
>         int err;
> @@ -2830,7 +2833,7 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,
>         int err;
>
>         link = container_of(fp, struct bpf_kprobe_multi_link, fp);
> -       err = kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
> +       err = kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs, false);
>         return link->is_wrapper ? err : 0;
>  }
>
> @@ -2842,7 +2845,7 @@ kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip,
>         struct bpf_kprobe_multi_link *link;
>
>         link = container_of(fp, struct bpf_kprobe_multi_link, fp);
> -       kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
> +       kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs, true);
>  }
>
>  static int symbols_cmp_r(const void *a, const void *b, const void *priv)
> @@ -3111,6 +3114,46 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
>         kvfree(cookies);
>         return err;
>  }
> +
> +__bpf_kfunc_start_defs();
> +
> +__bpf_kfunc bool bpf_kprobe_multi_is_return(void)

and for uprobes we'll have bpf_uprobe_multi_is_return?...

BTW, have you tried implementing a "session cookie" idea?


> +{
> +       struct bpf_kprobe_multi_run_ctx *run_ctx;
> +
> +       run_ctx = container_of(current->bpf_ctx, struct bpf_kprobe_multi_run_ctx, run_ctx);
> +       return run_ctx->is_return;
> +}
> +
> +__bpf_kfunc_end_defs();
> +
> +BTF_KFUNCS_START(kprobe_multi_kfunc_set_ids)
> +BTF_ID_FLAGS(func, bpf_kprobe_multi_is_return)
> +BTF_KFUNCS_END(kprobe_multi_kfunc_set_ids)
> +
> +static int bpf_kprobe_multi_filter(const struct bpf_prog *prog, u32 kfunc_id)
> +{
> +       if (!btf_id_set8_contains(&kprobe_multi_kfunc_set_ids, kfunc_id))
> +               return 0;
> +
> +       if (prog->expected_attach_type != BPF_TRACE_KPROBE_MULTI)
> +               return -EACCES;
> +
> +       return 0;
> +}
> +
> +static const struct btf_kfunc_id_set bpf_kprobe_multi_kfunc_set = {
> +       .owner = THIS_MODULE,
> +       .set = &kprobe_multi_kfunc_set_ids,
> +       .filter = bpf_kprobe_multi_filter,
> +};
> +
> +static int __init bpf_kprobe_multi_kfuncs_init(void)
> +{
> +       return register_btf_kfunc_id_set(BPF_PROG_TYPE_KPROBE, &bpf_kprobe_multi_kfunc_set);
> +}
> +
> +late_initcall(bpf_kprobe_multi_kfuncs_init);
>  #else /* !CONFIG_FPROBE */
>  int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
>  {
> --
> 2.43.2
>
Jiri Olsa Feb. 29, 2024, 10:16 a.m. UTC | #2 
On Wed, Feb 28, 2024 at 05:23:45PM -0800, Andrii Nakryiko wrote:

SNIP

> >  static int
> >  kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
> > -                          unsigned long entry_ip, struct pt_regs *regs)
> > +                          unsigned long entry_ip, struct pt_regs *regs,
> > +                          bool is_return)
> >  {
> >         struct bpf_kprobe_multi_run_ctx run_ctx = {
> >                 .link = link,
> >                 .entry_ip = entry_ip,
> > +               .is_return = is_return,
> >         };
> >         struct bpf_run_ctx *old_run_ctx;
> >         int err;
> > @@ -2830,7 +2833,7 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,
> >         int err;
> >
> >         link = container_of(fp, struct bpf_kprobe_multi_link, fp);
> > -       err = kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
> > +       err = kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs, false);
> >         return link->is_wrapper ? err : 0;
> >  }
> >
> > @@ -2842,7 +2845,7 @@ kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip,
> >         struct bpf_kprobe_multi_link *link;
> >
> >         link = container_of(fp, struct bpf_kprobe_multi_link, fp);
> > -       kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
> > +       kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs, true);
> >  }
> >
> >  static int symbols_cmp_r(const void *a, const void *b, const void *priv)
> > @@ -3111,6 +3114,46 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
> >         kvfree(cookies);
> >         return err;
> >  }
> > +
> > +__bpf_kfunc_start_defs();
> > +
> > +__bpf_kfunc bool bpf_kprobe_multi_is_return(void)
> 
> and for uprobes we'll have bpf_uprobe_multi_is_return?...

yes, but now I'm thinking maybe we could also have 'session' api and
have single 'bpf_session_is_return' because both kprobe and uprobe
are KPROBE program type.. and align it together with other session
kfuncs:

  bpf_session_is_return
  bpf_session_set_cookie
  bpf_session_get_cookie

> 
> BTW, have you tried implementing a "session cookie" idea?

yep, with a little fix [0] it's working on top of Masami's 'fprobe over fgraph'
changes, you can check last 2 patches in [1] .. I did not do this on top of the
current fprobe/rethook kernel code, because it seems it's about to go away

I still need to implement that on top of uprobes and I will send rfc, so we can
see all of it and discuss the interface

jirka


[0] https://lore.kernel.org/bpf/ZdyKaRiI-PnG80Q0@krava/
[1] https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git/log/?h=bpf/session_data

> 
> 
> > +{
> > +       struct bpf_kprobe_multi_run_ctx *run_ctx;
> > +
> > +       run_ctx = container_of(current->bpf_ctx, struct bpf_kprobe_multi_run_ctx, run_ctx);
> > +       return run_ctx->is_return;
> > +}
> > +
> > +__bpf_kfunc_end_defs();
> > +
> > +BTF_KFUNCS_START(kprobe_multi_kfunc_set_ids)
> > +BTF_ID_FLAGS(func, bpf_kprobe_multi_is_return)
> > +BTF_KFUNCS_END(kprobe_multi_kfunc_set_ids)
> > +
> > +static int bpf_kprobe_multi_filter(const struct bpf_prog *prog, u32 kfunc_id)
> > +{
> > +       if (!btf_id_set8_contains(&kprobe_multi_kfunc_set_ids, kfunc_id))
> > +               return 0;
> > +
> > +       if (prog->expected_attach_type != BPF_TRACE_KPROBE_MULTI)
> > +               return -EACCES;
> > +
> > +       return 0;
> > +}
> > +
> > +static const struct btf_kfunc_id_set bpf_kprobe_multi_kfunc_set = {
> > +       .owner = THIS_MODULE,
> > +       .set = &kprobe_multi_kfunc_set_ids,
> > +       .filter = bpf_kprobe_multi_filter,
> > +};
> > +
> > +static int __init bpf_kprobe_multi_kfuncs_init(void)
> > +{
> > +       return register_btf_kfunc_id_set(BPF_PROG_TYPE_KPROBE, &bpf_kprobe_multi_kfunc_set);
> > +}
> > +
> > +late_initcall(bpf_kprobe_multi_kfuncs_init);
> >  #else /* !CONFIG_FPROBE */
> >  int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
> >  {
> > --
> > 2.43.2
> >
Andrii Nakryiko March 1, 2024, 6:01 p.m. UTC | #3 
On Thu, Feb 29, 2024 at 2:16 AM Jiri Olsa <olsajiri@gmail.com> wrote:
>
> On Wed, Feb 28, 2024 at 05:23:45PM -0800, Andrii Nakryiko wrote:
>
> SNIP
>
> > >  static int
> > >  kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
> > > -                          unsigned long entry_ip, struct pt_regs *regs)
> > > +                          unsigned long entry_ip, struct pt_regs *regs,
> > > +                          bool is_return)
> > >  {
> > >         struct bpf_kprobe_multi_run_ctx run_ctx = {
> > >                 .link = link,
> > >                 .entry_ip = entry_ip,
> > > +               .is_return = is_return,
> > >         };
> > >         struct bpf_run_ctx *old_run_ctx;
> > >         int err;
> > > @@ -2830,7 +2833,7 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,
> > >         int err;
> > >
> > >         link = container_of(fp, struct bpf_kprobe_multi_link, fp);
> > > -       err = kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
> > > +       err = kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs, false);
> > >         return link->is_wrapper ? err : 0;
> > >  }
> > >
> > > @@ -2842,7 +2845,7 @@ kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip,
> > >         struct bpf_kprobe_multi_link *link;
> > >
> > >         link = container_of(fp, struct bpf_kprobe_multi_link, fp);
> > > -       kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
> > > +       kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs, true);
> > >  }
> > >
> > >  static int symbols_cmp_r(const void *a, const void *b, const void *priv)
> > > @@ -3111,6 +3114,46 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
> > >         kvfree(cookies);
> > >         return err;
> > >  }
> > > +
> > > +__bpf_kfunc_start_defs();
> > > +
> > > +__bpf_kfunc bool bpf_kprobe_multi_is_return(void)
> >
> > and for uprobes we'll have bpf_uprobe_multi_is_return?...
>
> yes, but now I'm thinking maybe we could also have 'session' api and
> have single 'bpf_session_is_return' because both kprobe and uprobe
> are KPROBE program type.. and align it together with other session
> kfuncs:
>
>   bpf_session_is_return
>   bpf_session_set_cookie
>   bpf_session_get_cookie
>

We can do that. But I was thinking more of a

u64 *bpf_session_cookie()

which would return a read/write pointer that BPF program can
manipulate. Instead of doing two calls (get_cookie + set_cookie), it
would be one call. Is there any benefit to having separate set/get
cookie calls?

> >
> > BTW, have you tried implementing a "session cookie" idea?
>
> yep, with a little fix [0] it's working on top of Masami's 'fprobe over fgraph'
> changes, you can check last 2 patches in [1] .. I did not do this on top of the
> current fprobe/rethook kernel code, because it seems it's about to go away

do you know what is the timeline for fprobe over fgraph work to be finished?

>
> I still need to implement that on top of uprobes and I will send rfc, so we can
> see all of it and discuss the interface
>

great, yeah, I think the session cookie idea should go in at the same
time, if possible, so that we can assume it is supported for new
[ku]probe.wrapper programs.


> jirka
>
>
> [0] https://lore.kernel.org/bpf/ZdyKaRiI-PnG80Q0@krava/
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git/log/?h=bpf/session_data
>
> >
> >
> > > +{
> > > +       struct bpf_kprobe_multi_run_ctx *run_ctx;
> > > +
> > > +       run_ctx = container_of(current->bpf_ctx, struct bpf_kprobe_multi_run_ctx, run_ctx);
> > > +       return run_ctx->is_return;
> > > +}
> > > +
> > > +__bpf_kfunc_end_defs();
> > > +
> > > +BTF_KFUNCS_START(kprobe_multi_kfunc_set_ids)
> > > +BTF_ID_FLAGS(func, bpf_kprobe_multi_is_return)
> > > +BTF_KFUNCS_END(kprobe_multi_kfunc_set_ids)
> > > +
> > > +static int bpf_kprobe_multi_filter(const struct bpf_prog *prog, u32 kfunc_id)
> > > +{
> > > +       if (!btf_id_set8_contains(&kprobe_multi_kfunc_set_ids, kfunc_id))
> > > +               return 0;
> > > +
> > > +       if (prog->expected_attach_type != BPF_TRACE_KPROBE_MULTI)
> > > +               return -EACCES;
> > > +
> > > +       return 0;
> > > +}
> > > +
> > > +static const struct btf_kfunc_id_set bpf_kprobe_multi_kfunc_set = {
> > > +       .owner = THIS_MODULE,
> > > +       .set = &kprobe_multi_kfunc_set_ids,
> > > +       .filter = bpf_kprobe_multi_filter,
> > > +};
> > > +
> > > +static int __init bpf_kprobe_multi_kfuncs_init(void)
> > > +{
> > > +       return register_btf_kfunc_id_set(BPF_PROG_TYPE_KPROBE, &bpf_kprobe_multi_kfunc_set);
> > > +}
> > > +
> > > +late_initcall(bpf_kprobe_multi_kfuncs_init);
> > >  #else /* !CONFIG_FPROBE */
> > >  int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
> > >  {
> > > --
> > > 2.43.2
> > >
Jiri Olsa March 4, 2024, 8:28 a.m. UTC | #4 
On Fri, Mar 01, 2024 at 10:01:16AM -0800, Andrii Nakryiko wrote:

sNIP

> > > > +__bpf_kfunc bool bpf_kprobe_multi_is_return(void)
> > >
> > > and for uprobes we'll have bpf_uprobe_multi_is_return?...
> >
> > yes, but now I'm thinking maybe we could also have 'session' api and
> > have single 'bpf_session_is_return' because both kprobe and uprobe
> > are KPROBE program type.. and align it together with other session
> > kfuncs:
> >
> >   bpf_session_is_return
> >   bpf_session_set_cookie
> >   bpf_session_get_cookie
> >
> 
> We can do that. But I was thinking more of a
> 
> u64 *bpf_session_cookie()
> 
> which would return a read/write pointer that BPF program can
> manipulate. Instead of doing two calls (get_cookie + set_cookie), it
> would be one call. Is there any benefit to having separate set/get
> cookie calls?

ok, that would be easier, will check on that

> 
> > >
> > > BTW, have you tried implementing a "session cookie" idea?
> >
> > yep, with a little fix [0] it's working on top of Masami's 'fprobe over fgraph'
> > changes, you can check last 2 patches in [1] .. I did not do this on top of the
> > current fprobe/rethook kernel code, because it seems it's about to go away
> 
> do you know what is the timeline for fprobe over fgraph work to be finished?

good question ;-) Masami, any idea?

fwiw there's new version needed for [1] fix

[1] https://lore.kernel.org/bpf/ZdyKaRiI-PnG80Q0@krava/

> 
> >
> > I still need to implement that on top of uprobes and I will send rfc, so we can
> > see all of it and discuss the interface
> >
> 
> great, yeah, I think the session cookie idea should go in at the same
> time, if possible, so that we can assume it is supported for new
> [ku]probe.wrapper programs.

makes sense, even though with new kfuncs detection stuff,
it will be easy to find out

jirka
diff mbox series

Patch

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 6ff0bd1a91d5..5ab55720e881 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -218,6 +218,7 @@  enum btf_kfunc_hook {
 	BTF_KFUNC_HOOK_SOCKET_FILTER,
 	BTF_KFUNC_HOOK_LWT,
 	BTF_KFUNC_HOOK_NETFILTER,
+	BTF_KFUNC_HOOK_KPROBE,
 	BTF_KFUNC_HOOK_MAX,
 };
 
@@ -8112,6 +8113,8 @@  static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
 		return BTF_KFUNC_HOOK_LWT;
 	case BPF_PROG_TYPE_NETFILTER:
 		return BTF_KFUNC_HOOK_NETFILTER;
+	case BPF_PROG_TYPE_KPROBE:
+		return BTF_KFUNC_HOOK_KPROBE;
 	default:
 		return BTF_KFUNC_HOOK_MAX;
 	}
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 726a8c71f0da..cb801c94b8fa 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2594,6 +2594,7 @@  struct bpf_kprobe_multi_run_ctx {
 	struct bpf_run_ctx run_ctx;
 	struct bpf_kprobe_multi_link *link;
 	unsigned long entry_ip;
+	bool is_return;
 };
 
 struct user_syms {
@@ -2793,11 +2794,13 @@  static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx)
 
 static int
 kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
-			   unsigned long entry_ip, struct pt_regs *regs)
+			   unsigned long entry_ip, struct pt_regs *regs,
+			   bool is_return)
 {
 	struct bpf_kprobe_multi_run_ctx run_ctx = {
 		.link = link,
 		.entry_ip = entry_ip,
+		.is_return = is_return,
 	};
 	struct bpf_run_ctx *old_run_ctx;
 	int err;
@@ -2830,7 +2833,7 @@  kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,
 	int err;
 
 	link = container_of(fp, struct bpf_kprobe_multi_link, fp);
-	err = kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
+	err = kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs, false);
 	return link->is_wrapper ? err : 0;
 }
 
@@ -2842,7 +2845,7 @@  kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip,
 	struct bpf_kprobe_multi_link *link;
 
 	link = container_of(fp, struct bpf_kprobe_multi_link, fp);
-	kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
+	kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs, true);
 }
 
 static int symbols_cmp_r(const void *a, const void *b, const void *priv)
@@ -3111,6 +3114,46 @@  int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 	kvfree(cookies);
 	return err;
 }
+
+__bpf_kfunc_start_defs();
+
+__bpf_kfunc bool bpf_kprobe_multi_is_return(void)
+{
+	struct bpf_kprobe_multi_run_ctx *run_ctx;
+
+	run_ctx = container_of(current->bpf_ctx, struct bpf_kprobe_multi_run_ctx, run_ctx);
+	return run_ctx->is_return;
+}
+
+__bpf_kfunc_end_defs();
+
+BTF_KFUNCS_START(kprobe_multi_kfunc_set_ids)
+BTF_ID_FLAGS(func, bpf_kprobe_multi_is_return)
+BTF_KFUNCS_END(kprobe_multi_kfunc_set_ids)
+
+static int bpf_kprobe_multi_filter(const struct bpf_prog *prog, u32 kfunc_id)
+{
+	if (!btf_id_set8_contains(&kprobe_multi_kfunc_set_ids, kfunc_id))
+		return 0;
+
+	if (prog->expected_attach_type != BPF_TRACE_KPROBE_MULTI)
+		return -EACCES;
+
+	return 0;
+}
+
+static const struct btf_kfunc_id_set bpf_kprobe_multi_kfunc_set = {
+	.owner = THIS_MODULE,
+	.set = &kprobe_multi_kfunc_set_ids,
+	.filter = bpf_kprobe_multi_filter,
+};
+
+static int __init bpf_kprobe_multi_kfuncs_init(void)
+{
+	return register_btf_kfunc_id_set(BPF_PROG_TYPE_KPROBE, &bpf_kprobe_multi_kfunc_set);
+}
+
+late_initcall(bpf_kprobe_multi_kfuncs_init);
 #else /* !CONFIG_FPROBE */
 int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
 {