[PATCH v3] libbpf: Cleanup the legacy kprobe_event on failed add/attach_event()

[PATCH v3] libbpf: Cleanup the legacy kprobe_event on failed add/attach_event()

[Chuang W]

Before the 0bc11ed5ab60 commit ("kprobes: Allow kprobes coexist with
livepatch"), in a scenario where livepatch and kprobe coexist on the
same function entry, the creation of kprobe_event using
add_kprobe_event_legacy() will be successful, at the same time as a
trace event (e.g. /debugfs/tracing/events/kprobe/XXX) will exist, but
perf_event_open() will return an error because both livepatch and kprobe
use FTRACE_OPS_FL_IPMODIFY. As follows:

1) add a livepatch

$ insmod livepatch-XXX.ko

2) add a kprobe using tracefs API (i.e. add_kprobe_event_legacy)

$ echo 'p:mykprobe XXX' > /sys/kernel/debug/tracing/kprobe_events

3) enable this kprobe (i.e. sys_perf_event_open)

This will return an error, -EBUSY.

On Andrii Nakryiko's comment, few error paths in
bpf_program__attach_kprobe_opts() which should need to call
remove_kprobe_event_legacy().

With this patch, whenever an error is returned after
add_kprobe_event_legacy() or bpf_program__attach_perf_event_opts(), this
ensures that the created kprobe_event is cleaned.

Signed-off-by: Chuang W <nashuiliang@gmail.com>
Signed-off-by: Jingren Zhou <zhoujingren@didiglobal.com>
---
V2->v3:
- add detail commits
- call remove_kprobe_event_legacy() on failed bpf_program__attach_perf_event_opts()

 tools/lib/bpf/libbpf.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 49e359cd34df..038b0cb3313f 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -10811,10 +10811,11 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
 	}
 	type = determine_kprobe_perf_type_legacy(probe_name, retprobe);
 	if (type < 0) {
+		err = type;
 		pr_warn("failed to determine legacy kprobe event id for '%s+0x%zx': %s\n",
 			kfunc_name, offset,
-			libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
-		return type;
+			libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
+		goto clear_kprobe_event;
 	}
 	attr.size = sizeof(attr);
 	attr.config = type;
@@ -10828,9 +10829,14 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
 		err = -errno;
 		pr_warn("legacy kprobe perf_event_open() failed: %s\n",
 			libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
-		return err;
+		goto clear_kprobe_event;
 	}
 	return pfd;
+
+clear_kprobe_event:
+	/* Clear the newly added legacy kprobe_event */
+	remove_kprobe_event_legacy(probe_name, retprobe);
+	return err;
 }
 
 struct bpf_link *
@@ -10899,6 +10905,9 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
 
 	return link;
 err_out:
+	/* Clear the newly added legacy kprobe_event */
+	if (legacy)
+		remove_kprobe_event_legacy(legacy_probe, retprobe);
 	free(legacy_probe);
 	return libbpf_err_ptr(err);
 }
-- 
2.34.1

Re: [PATCH v3] libbpf: Cleanup the legacy kprobe_event on failed add/attach_event()

[Andrii Nakryiko]

On Sat, Jun 25, 2022 at 8:13 PM Chuang W <nashuiliang@gmail.com> wrote:
>
> Before the 0bc11ed5ab60 commit ("kprobes: Allow kprobes coexist with
> livepatch"), in a scenario where livepatch and kprobe coexist on the
> same function entry, the creation of kprobe_event using
> add_kprobe_event_legacy() will be successful, at the same time as a
> trace event (e.g. /debugfs/tracing/events/kprobe/XXX) will exist, but
> perf_event_open() will return an error because both livepatch and kprobe
> use FTRACE_OPS_FL_IPMODIFY. As follows:
>
> 1) add a livepatch
>
> $ insmod livepatch-XXX.ko
>
> 2) add a kprobe using tracefs API (i.e. add_kprobe_event_legacy)
>
> $ echo 'p:mykprobe XXX' > /sys/kernel/debug/tracing/kprobe_events
>
> 3) enable this kprobe (i.e. sys_perf_event_open)
>
> This will return an error, -EBUSY.
>
> On Andrii Nakryiko's comment, few error paths in
> bpf_program__attach_kprobe_opts() which should need to call
> remove_kprobe_event_legacy().
>
> With this patch, whenever an error is returned after
> add_kprobe_event_legacy() or bpf_program__attach_perf_event_opts(), this
> ensures that the created kprobe_event is cleaned.
>
> Signed-off-by: Chuang W <nashuiliang@gmail.com>

Is this your full name? Signed-off-by is required to have a full name
of a person, please update if it's not

> Signed-off-by: Jingren Zhou <zhoujingren@didiglobal.com>
> ---
> V2->v3:
> - add detail commits
> - call remove_kprobe_event_legacy() on failed bpf_program__attach_perf_event_opts()
>
>  tools/lib/bpf/libbpf.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 49e359cd34df..038b0cb3313f 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -10811,10 +10811,11 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
>         }
>         type = determine_kprobe_perf_type_legacy(probe_name, retprobe);
>         if (type < 0) {
> +               err = type;
>                 pr_warn("failed to determine legacy kprobe event id for '%s+0x%zx': %s\n",
>                         kfunc_name, offset,
> -                       libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
> -               return type;
> +                       libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
> +               goto clear_kprobe_event;
>         }
>         attr.size = sizeof(attr);
>         attr.config = type;
> @@ -10828,9 +10829,14 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
>                 err = -errno;
>                 pr_warn("legacy kprobe perf_event_open() failed: %s\n",
>                         libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
> -               return err;
> +               goto clear_kprobe_event;
>         }
>         return pfd;
> +
> +clear_kprobe_event:
> +       /* Clear the newly added legacy kprobe_event */
> +       remove_kprobe_event_legacy(probe_name, retprobe);
> +       return err;
>  }
>

this part looks good


>  struct bpf_link *
> @@ -10899,6 +10905,9 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
>
>         return link;
>  err_out:
> +       /* Clear the newly added legacy kprobe_event */
> +       if (legacy)
> +               remove_kprobe_event_legacy(legacy_probe, retprobe);

this one will call remove_kprobe_event_legacy() even if we failed to
create that kprobe_event in the first place. So let's maybe add

err_clean_legacy:
    if (legacy)
         remove_kprobe_event_legacy(legacy_probe, retprobe);

before err_out: and goto there if we fail to attach (but not if we
fail to create pfd)?


Also, looking through libbpf code, I realized that we have exactly the
same problem for uprobes, so please add same fixed to
perf_event_uprobe_open_legacy and attach_uprobe_opts. Thanks!




>         free(legacy_probe);
>         return libbpf_err_ptr(err);
>  }
> --
> 2.34.1
>

Re: [PATCH v3] libbpf: Cleanup the legacy kprobe_event on failed add/attach_event()

[Chuang W]

Hi Andrii,

On Tue, Jun 28, 2022 at 5:27 AM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Sat, Jun 25, 2022 at 8:13 PM Chuang W <nashuiliang@gmail.com> wrote:
> >
> > Before the 0bc11ed5ab60 commit ("kprobes: Allow kprobes coexist with
> > livepatch"), in a scenario where livepatch and kprobe coexist on the
> > same function entry, the creation of kprobe_event using
> > add_kprobe_event_legacy() will be successful, at the same time as a
> > trace event (e.g. /debugfs/tracing/events/kprobe/XXX) will exist, but
> > perf_event_open() will return an error because both livepatch and kprobe
> > use FTRACE_OPS_FL_IPMODIFY. As follows:
> >
> > 1) add a livepatch
> >
> > $ insmod livepatch-XXX.ko
> >
> > 2) add a kprobe using tracefs API (i.e. add_kprobe_event_legacy)
> >
> > $ echo 'p:mykprobe XXX' > /sys/kernel/debug/tracing/kprobe_events
> >
> > 3) enable this kprobe (i.e. sys_perf_event_open)
> >
> > This will return an error, -EBUSY.
> >
> > On Andrii Nakryiko's comment, few error paths in
> > bpf_program__attach_kprobe_opts() which should need to call
> > remove_kprobe_event_legacy().
> >
> > With this patch, whenever an error is returned after
> > add_kprobe_event_legacy() or bpf_program__attach_perf_event_opts(), this
> > ensures that the created kprobe_event is cleaned.
> >
> > Signed-off-by: Chuang W <nashuiliang@gmail.com>
>
> Is this your full name? Signed-off-by is required to have a full name
> of a person, please update if it's not
>
> > Signed-off-by: Jingren Zhou <zhoujingren@didiglobal.com>
> > ---
> > V2->v3:
> > - add detail commits
> > - call remove_kprobe_event_legacy() on failed bpf_program__attach_perf_event_opts()
> >
> >  tools/lib/bpf/libbpf.c | 15 ++++++++++++---
> >  1 file changed, 12 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > index 49e359cd34df..038b0cb3313f 100644
> > --- a/tools/lib/bpf/libbpf.c
> > +++ b/tools/lib/bpf/libbpf.c
> > @@ -10811,10 +10811,11 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
> >         }
> >         type = determine_kprobe_perf_type_legacy(probe_name, retprobe);
> >         if (type < 0) {
> > +               err = type;
> >                 pr_warn("failed to determine legacy kprobe event id for '%s+0x%zx': %s\n",
> >                         kfunc_name, offset,
> > -                       libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
> > -               return type;
> > +                       libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
> > +               goto clear_kprobe_event;
> >         }
> >         attr.size = sizeof(attr);
> >         attr.config = type;
> > @@ -10828,9 +10829,14 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
> >                 err = -errno;
> >                 pr_warn("legacy kprobe perf_event_open() failed: %s\n",
> >                         libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
> > -               return err;
> > +               goto clear_kprobe_event;
> >         }
> >         return pfd;
> > +
> > +clear_kprobe_event:
> > +       /* Clear the newly added legacy kprobe_event */
> > +       remove_kprobe_event_legacy(probe_name, retprobe);
> > +       return err;
> >  }
> >
>
> this part looks good
>
>
> >  struct bpf_link *
> > @@ -10899,6 +10905,9 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
> >
> >         return link;
> >  err_out:
> > +       /* Clear the newly added legacy kprobe_event */
> > +       if (legacy)
> > +               remove_kprobe_event_legacy(legacy_probe, retprobe);
>
> this one will call remove_kprobe_event_legacy() even if we failed to
> create that kprobe_event in the first place. So let's maybe add
>
> err_clean_legacy:
>     if (legacy)
>          remove_kprobe_event_legacy(legacy_probe, retprobe);
>
> before err_out: and goto there if we fail to attach (but not if we
> fail to create pfd)?
>

Nice, I will modify it.

>
> Also, looking through libbpf code, I realized that we have exactly the
> same problem for uprobes, so please add same fixed to
> perf_event_uprobe_open_legacy and attach_uprobe_opts. Thanks!
>

Oh, yes. I also noticed this problem for uprobes, I was planning to
submit a patch for uprobes.
Do you think I should submit another patch for uprobes or combine
kprobes and uprobes into one?

Thanks,
>
>
> >         free(legacy_probe);
> >         return libbpf_err_ptr(err);
> >  }
> > --
> > 2.34.1
> >

Re: [PATCH v3] libbpf: Cleanup the legacy kprobe_event on failed add/attach_event()

[Andrii Nakryiko]

On Mon, Jun 27, 2022 at 6:51 PM Chuang W <nashuiliang@gmail.com> wrote:
>
> Hi Andrii,
>
> On Tue, Jun 28, 2022 at 5:27 AM Andrii Nakryiko
> <andrii.nakryiko@gmail.com> wrote:
> >
> > On Sat, Jun 25, 2022 at 8:13 PM Chuang W <nashuiliang@gmail.com> wrote:
> > >
> > > Before the 0bc11ed5ab60 commit ("kprobes: Allow kprobes coexist with
> > > livepatch"), in a scenario where livepatch and kprobe coexist on the
> > > same function entry, the creation of kprobe_event using
> > > add_kprobe_event_legacy() will be successful, at the same time as a
> > > trace event (e.g. /debugfs/tracing/events/kprobe/XXX) will exist, but
> > > perf_event_open() will return an error because both livepatch and kprobe
> > > use FTRACE_OPS_FL_IPMODIFY. As follows:
> > >
> > > 1) add a livepatch
> > >
> > > $ insmod livepatch-XXX.ko
> > >
> > > 2) add a kprobe using tracefs API (i.e. add_kprobe_event_legacy)
> > >
> > > $ echo 'p:mykprobe XXX' > /sys/kernel/debug/tracing/kprobe_events
> > >
> > > 3) enable this kprobe (i.e. sys_perf_event_open)
> > >
> > > This will return an error, -EBUSY.
> > >
> > > On Andrii Nakryiko's comment, few error paths in
> > > bpf_program__attach_kprobe_opts() which should need to call
> > > remove_kprobe_event_legacy().
> > >
> > > With this patch, whenever an error is returned after
> > > add_kprobe_event_legacy() or bpf_program__attach_perf_event_opts(), this
> > > ensures that the created kprobe_event is cleaned.
> > >
> > > Signed-off-by: Chuang W <nashuiliang@gmail.com>
> >
> > Is this your full name? Signed-off-by is required to have a full name
> > of a person, please update if it's not
> >
> > > Signed-off-by: Jingren Zhou <zhoujingren@didiglobal.com>
> > > ---
> > > V2->v3:
> > > - add detail commits
> > > - call remove_kprobe_event_legacy() on failed bpf_program__attach_perf_event_opts()
> > >
> > >  tools/lib/bpf/libbpf.c | 15 ++++++++++++---
> > >  1 file changed, 12 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > > index 49e359cd34df..038b0cb3313f 100644
> > > --- a/tools/lib/bpf/libbpf.c
> > > +++ b/tools/lib/bpf/libbpf.c
> > > @@ -10811,10 +10811,11 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
> > >         }
> > >         type = determine_kprobe_perf_type_legacy(probe_name, retprobe);
> > >         if (type < 0) {
> > > +               err = type;
> > >                 pr_warn("failed to determine legacy kprobe event id for '%s+0x%zx': %s\n",
> > >                         kfunc_name, offset,
> > > -                       libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
> > > -               return type;
> > > +                       libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
> > > +               goto clear_kprobe_event;
> > >         }
> > >         attr.size = sizeof(attr);
> > >         attr.config = type;
> > > @@ -10828,9 +10829,14 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
> > >                 err = -errno;
> > >                 pr_warn("legacy kprobe perf_event_open() failed: %s\n",
> > >                         libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
> > > -               return err;
> > > +               goto clear_kprobe_event;
> > >         }
> > >         return pfd;
> > > +
> > > +clear_kprobe_event:
> > > +       /* Clear the newly added legacy kprobe_event */
> > > +       remove_kprobe_event_legacy(probe_name, retprobe);
> > > +       return err;
> > >  }
> > >
> >
> > this part looks good
> >
> >
> > >  struct bpf_link *
> > > @@ -10899,6 +10905,9 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
> > >
> > >         return link;
> > >  err_out:
> > > +       /* Clear the newly added legacy kprobe_event */
> > > +       if (legacy)
> > > +               remove_kprobe_event_legacy(legacy_probe, retprobe);
> >
> > this one will call remove_kprobe_event_legacy() even if we failed to
> > create that kprobe_event in the first place. So let's maybe add
> >
> > err_clean_legacy:
> >     if (legacy)
> >          remove_kprobe_event_legacy(legacy_probe, retprobe);
> >
> > before err_out: and goto there if we fail to attach (but not if we
> > fail to create pfd)?
> >
>
> Nice, I will modify it.
>
> >
> > Also, looking through libbpf code, I realized that we have exactly the
> > same problem for uprobes, so please add same fixed to
> > perf_event_uprobe_open_legacy and attach_uprobe_opts. Thanks!
> >
>
> Oh, yes. I also noticed this problem for uprobes, I was planning to
> submit a patch for uprobes.
> Do you think I should submit another patch for uprobes or combine
> kprobes and uprobes into one?
>

two separate patches make more sense, but send them as a patch series?

> Thanks,
> >
> >
> > >         free(legacy_probe);
> > >         return libbpf_err_ptr(err);
> > >  }
> > > --
> > > 2.34.1
> > >

Re: [PATCH v3] libbpf: Cleanup the legacy kprobe_event on failed add/attach_event()

[Chuang W]

Ok.

Thanks,

On Tue, Jun 28, 2022 at 10:35 AM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Mon, Jun 27, 2022 at 6:51 PM Chuang W <nashuiliang@gmail.com> wrote:
> >
> > Hi Andrii,
> >
> > On Tue, Jun 28, 2022 at 5:27 AM Andrii Nakryiko
> > <andrii.nakryiko@gmail.com> wrote:
> > >
> > > On Sat, Jun 25, 2022 at 8:13 PM Chuang W <nashuiliang@gmail.com> wrote:
> > > >
> > > > Before the 0bc11ed5ab60 commit ("kprobes: Allow kprobes coexist with
> > > > livepatch"), in a scenario where livepatch and kprobe coexist on the
> > > > same function entry, the creation of kprobe_event using
> > > > add_kprobe_event_legacy() will be successful, at the same time as a
> > > > trace event (e.g. /debugfs/tracing/events/kprobe/XXX) will exist, but
> > > > perf_event_open() will return an error because both livepatch and kprobe
> > > > use FTRACE_OPS_FL_IPMODIFY. As follows:
> > > >
> > > > 1) add a livepatch
> > > >
> > > > $ insmod livepatch-XXX.ko
> > > >
> > > > 2) add a kprobe using tracefs API (i.e. add_kprobe_event_legacy)
> > > >
> > > > $ echo 'p:mykprobe XXX' > /sys/kernel/debug/tracing/kprobe_events
> > > >
> > > > 3) enable this kprobe (i.e. sys_perf_event_open)
> > > >
> > > > This will return an error, -EBUSY.
> > > >
> > > > On Andrii Nakryiko's comment, few error paths in
> > > > bpf_program__attach_kprobe_opts() which should need to call
> > > > remove_kprobe_event_legacy().
> > > >
> > > > With this patch, whenever an error is returned after
> > > > add_kprobe_event_legacy() or bpf_program__attach_perf_event_opts(), this
> > > > ensures that the created kprobe_event is cleaned.
> > > >
> > > > Signed-off-by: Chuang W <nashuiliang@gmail.com>
> > >
> > > Is this your full name? Signed-off-by is required to have a full name
> > > of a person, please update if it's not
> > >
> > > > Signed-off-by: Jingren Zhou <zhoujingren@didiglobal.com>
> > > > ---
> > > > V2->v3:
> > > > - add detail commits
> > > > - call remove_kprobe_event_legacy() on failed bpf_program__attach_perf_event_opts()
> > > >
> > > >  tools/lib/bpf/libbpf.c | 15 ++++++++++++---
> > > >  1 file changed, 12 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > > > index 49e359cd34df..038b0cb3313f 100644
> > > > --- a/tools/lib/bpf/libbpf.c
> > > > +++ b/tools/lib/bpf/libbpf.c
> > > > @@ -10811,10 +10811,11 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
> > > >         }
> > > >         type = determine_kprobe_perf_type_legacy(probe_name, retprobe);
> > > >         if (type < 0) {
> > > > +               err = type;
> > > >                 pr_warn("failed to determine legacy kprobe event id for '%s+0x%zx': %s\n",
> > > >                         kfunc_name, offset,
> > > > -                       libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
> > > > -               return type;
> > > > +                       libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
> > > > +               goto clear_kprobe_event;
> > > >         }
> > > >         attr.size = sizeof(attr);
> > > >         attr.config = type;
> > > > @@ -10828,9 +10829,14 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
> > > >                 err = -errno;
> > > >                 pr_warn("legacy kprobe perf_event_open() failed: %s\n",
> > > >                         libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
> > > > -               return err;
> > > > +               goto clear_kprobe_event;
> > > >         }
> > > >         return pfd;
> > > > +
> > > > +clear_kprobe_event:
> > > > +       /* Clear the newly added legacy kprobe_event */
> > > > +       remove_kprobe_event_legacy(probe_name, retprobe);
> > > > +       return err;
> > > >  }
> > > >
> > >
> > > this part looks good
> > >
> > >
> > > >  struct bpf_link *
> > > > @@ -10899,6 +10905,9 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
> > > >
> > > >         return link;
> > > >  err_out:
> > > > +       /* Clear the newly added legacy kprobe_event */
> > > > +       if (legacy)
> > > > +               remove_kprobe_event_legacy(legacy_probe, retprobe);
> > >
> > > this one will call remove_kprobe_event_legacy() even if we failed to
> > > create that kprobe_event in the first place. So let's maybe add
> > >
> > > err_clean_legacy:
> > >     if (legacy)
> > >          remove_kprobe_event_legacy(legacy_probe, retprobe);
> > >
> > > before err_out: and goto there if we fail to attach (but not if we
> > > fail to create pfd)?
> > >
> >
> > Nice, I will modify it.
> >
> > >
> > > Also, looking through libbpf code, I realized that we have exactly the
> > > same problem for uprobes, so please add same fixed to
> > > perf_event_uprobe_open_legacy and attach_uprobe_opts. Thanks!
> > >
> >
> > Oh, yes. I also noticed this problem for uprobes, I was planning to
> > submit a patch for uprobes.
> > Do you think I should submit another patch for uprobes or combine
> > kprobes and uprobes into one?
> >
>
> two separate patches make more sense, but send them as a patch series?
>
> > Thanks,
> > >
> > >
> > > >         free(legacy_probe);
> > > >         return libbpf_err_ptr(err);
> > > >  }
> > > > --
> > > > 2.34.1
> > > >