[v5,bpf-next,03/11] bpftool: Show kprobe_multi link info

Message ID	20230623141546.3751-4-laoar.shao@gmail.com (mailing list archive)
State	Superseded
Headers	show Return-Path: <linux-trace-kernel-owner@vger.kernel.org> From: Yafang Shao <laoar.shao@gmail.com> To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, quentin@isovalent.com, rostedt@goodmis.org, mhiramat@kernel.org Cc: bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Yafang Shao <laoar.shao@gmail.com> Subject: [PATCH v5 bpf-next 03/11] bpftool: Show kprobe_multi link info Date: Fri, 23 Jun 2023 14:15:38 +0000 Message-Id: <20230623141546.3751-4-laoar.shao@gmail.com> In-Reply-To: <20230623141546.3751-1-laoar.shao@gmail.com> References: <20230623141546.3751-1-laoar.shao@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk
Series	bpf: Support ->fill_link_info for kprobe_multi and perf_event links \| expand [v5,bpf-next,00/11] bpf: Support ->fill_link_info for kprobe_multi and perf_event links [v5,bpf-next,01/11] bpf: Support ->fill_link_info for kprobe_multi [v5,bpf-next,02/11] bpftool: Dump the kernel symbol's module name [v5,bpf-next,03/11] bpftool: Show kprobe_multi link info [v5,bpf-next,04/11] bpf: Protect probed address based on kptr_restrict setting [v5,bpf-next,05/11] bpf: Clear the probe_addr for uprobe [v5,bpf-next,06/11] bpf: Expose symbol's respective address [v5,bpf-next,07/11] bpf: Add a common helper bpf_copy_to_user() [v5,bpf-next,08/11] bpf: Add bpf_perf_link_fill_common() [v5,bpf-next,09/11] bpf: Support ->fill_link_info for perf_event [v5,bpf-next,10/11] bpftool: Add perf event names [v5,bpf-next,11/11] bpftool: Show perf link info

Message ID

20230623141546.3751-4-laoar.shao@gmail.com (mailing list archive)

State

Superseded

Headers

From: Yafang Shao <laoar.shao@gmail.com>
To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com,
        andrii@kernel.org, martin.lau@linux.dev, song@kernel.org,
        yhs@fb.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com,
        jolsa@kernel.org, quentin@isovalent.com, rostedt@goodmis.org,
        mhiramat@kernel.org
Cc: bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
        Yafang Shao <laoar.shao@gmail.com>
Subject: [PATCH v5 bpf-next 03/11] bpftool: Show kprobe_multi link info
Date: Fri, 23 Jun 2023 14:15:38 +0000
Message-Id: <20230623141546.3751-4-laoar.shao@gmail.com>
In-Reply-To: <20230623141546.3751-1-laoar.shao@gmail.com>
References: <20230623141546.3751-1-laoar.shao@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

Series

bpf: Support ->fill_link_info for kprobe_multi and perf_event links | expand

Commit Message

Yafang Shao June 23, 2023, 2:15 p.m. UTC

Show the already expose kprobe_multi link info in bpftool. The result as
follows,

$ tools/bpf/bpftool/bpftool link show
4: kprobe_multi  prog 22
        kprobe.multi  func_cnt 7
        addr             func [module]
        ffffffffbbc44f20 schedule_timeout_interruptible
        ffffffffbbc44f60 schedule_timeout_killable
        ffffffffbbc44fa0 schedule_timeout_uninterruptible
        ffffffffbbc44fe0 schedule_timeout_idle
        ffffffffc08028d0 xfs_trans_get_efd [xfs]
        ffffffffc080fa10 xfs_trans_get_buf_map [xfs]
        ffffffffc0813320 xfs_trans_get_dqtrx [xfs]
        pids kprobe_multi(1434978)
5: kprobe_multi  prog 22
        kretprobe.multi  func_cnt 7
        addr             func [module]
        ffffffffbbc44f20 schedule_timeout_interruptible
        ffffffffbbc44f60 schedule_timeout_killable
        ffffffffbbc44fa0 schedule_timeout_uninterruptible
        ffffffffbbc44fe0 schedule_timeout_idle
        ffffffffc08028d0 xfs_trans_get_efd [xfs]
        ffffffffc080fa10 xfs_trans_get_buf_map [xfs]
        ffffffffc0813320 xfs_trans_get_dqtrx [xfs]
        pids kprobe_multi(1434978)

$ tools/bpf/bpftool/bpftool link show -j
[{"id":4,"type":"kprobe_multi","prog_id":22,"retprobe":false,"func_cnt":7,"funcs":[{"addr":18446744072564789024,"func":"schedule_timeout_interruptible","module":""},{"addr":18446744072564789088,"func":"schedule_timeout_killable","module":""},{"addr":18446744072564789152,"func":"schedule_timeout_uninterruptible","module":""},{"addr":18446744072564789216,"func":"schedule_timeout_idle","module":""},{"addr":18446744072644208848,"func":"xfs_trans_get_efd","module":"xfs"},{"addr":18446744072644262416,"func":"xfs_trans_get_buf_map","module":"xfs"},{"addr":18446744072644277024,"func":"xfs_trans_get_dqtrx","module":"xfs"}],"pids":[{"pid":1434978,"comm":"kprobe_multi"}]},{"id":5,"type":"kprobe_multi","prog_id":22,"retprobe":true,"func_cnt":7,"funcs":[{"addr":18446744072564789024,"func":"schedule_timeout_interruptible","module":""},{"addr":18446744072564789088,"func":"schedule_timeout_killable","module":""},{"addr":18446744072564789152,"func":"schedule_timeout_uninterruptible","module":""},{"addr":18446744072564789216,"func":"schedule_timeout_idle","module":""},{"addr":18446744072644208848,"func":"xfs_trans_get_efd","module":"xfs"},{"addr":18446744072644262416,"func":"xfs_trans_get_buf_map","module":"xfs"},{"addr":18446744072644277024,"func":"xfs_trans_get_dqtrx","module":"xfs"}],"pids":[{"pid":1434978,"comm":"kprobe_multi"}]}]

When kptr_restrict is 2, the result is,

$ tools/bpf/bpftool/bpftool link show
4: kprobe_multi  prog 22
        kprobe.multi  func_cnt 7
5: kprobe_multi  prog 22
        kretprobe.multi  func_cnt 7

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
 tools/bpf/bpftool/link.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 108 insertions(+), 1 deletion(-)

Comments

Quentin Monnet June 23, 2023, 4:48 p.m. UTC | #1

2023-06-23 14:15 UTC+0000 ~ Yafang Shao <laoar.shao@gmail.com>
> Show the already expose kprobe_multi link info in bpftool. The result as
> follows,
> 
> $ tools/bpf/bpftool/bpftool link show
> 4: kprobe_multi  prog 22
>         kprobe.multi  func_cnt 7
>         addr             func [module]
>         ffffffffbbc44f20 schedule_timeout_interruptible
>         ffffffffbbc44f60 schedule_timeout_killable
>         ffffffffbbc44fa0 schedule_timeout_uninterruptible
>         ffffffffbbc44fe0 schedule_timeout_idle
>         ffffffffc08028d0 xfs_trans_get_efd [xfs]
>         ffffffffc080fa10 xfs_trans_get_buf_map [xfs]
>         ffffffffc0813320 xfs_trans_get_dqtrx [xfs]
>         pids kprobe_multi(1434978)
> 5: kprobe_multi  prog 22
>         kretprobe.multi  func_cnt 7
>         addr             func [module]
>         ffffffffbbc44f20 schedule_timeout_interruptible
>         ffffffffbbc44f60 schedule_timeout_killable
>         ffffffffbbc44fa0 schedule_timeout_uninterruptible
>         ffffffffbbc44fe0 schedule_timeout_idle
>         ffffffffc08028d0 xfs_trans_get_efd [xfs]
>         ffffffffc080fa10 xfs_trans_get_buf_map [xfs]
>         ffffffffc0813320 xfs_trans_get_dqtrx [xfs]
>         pids kprobe_multi(1434978)
> 
> $ tools/bpf/bpftool/bpftool link show -j
> [{"id":4,"type":"kprobe_multi","prog_id":22,"retprobe":false,"func_cnt":7,"funcs":[{"addr":18446744072564789024,"func":"schedule_timeout_interruptible","module":""},{"addr":18446744072564789088,"func":"schedule_timeout_killable","module":""},{"addr":18446744072564789152,"func":"schedule_timeout_uninterruptible","module":""},{"addr":18446744072564789216,"func":"schedule_timeout_idle","module":""},{"addr":18446744072644208848,"func":"xfs_trans_get_efd","module":"xfs"},{"addr":18446744072644262416,"func":"xfs_trans_get_buf_map","module":"xfs"},{"addr":18446744072644277024,"func":"xfs_trans_get_dqtrx","module":"xfs"}],"pids":[{"pid":1434978,"comm":"kprobe_multi"}]},{"id":5,"type":"kprobe_multi","prog_id":22,"retprobe":true,"func_cnt":7,"funcs":[{"addr":18446744072564789024,"func":"schedule_timeout_interruptible","module":""},{"addr":18446744072564789088,"func":"schedule_timeout_killable","module":""},{"addr":18446744072564789152,"func":"schedule_timeout_uninterruptible","module":""},{"addr":18446744072564789216,"func":"schedule_timeout_idle","module":""},{"addr":18446744072644208848,"func":"xfs_trans_get_efd","module":"xfs"},{"addr":18446744072644262416,"func":"xfs_trans_get_buf_map","module":"xfs"},{"addr":18446744072644277024,"func":"xfs_trans_get_dqtrx","module":"xfs"}],"pids":[{"pid":1434978,"comm":"kprobe_multi"}]}]
> 
> When kptr_restrict is 2, the result is,
> 
> $ tools/bpf/bpftool/bpftool link show
> 4: kprobe_multi  prog 22
>         kprobe.multi  func_cnt 7
> 5: kprobe_multi  prog 22
>         kretprobe.multi  func_cnt 7
> 
> Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
> ---
>  tools/bpf/bpftool/link.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 108 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
> index 2d78607..8461e6d 100644
> --- a/tools/bpf/bpftool/link.c
> +++ b/tools/bpf/bpftool/link.c
> @@ -14,8 +14,10 @@
>  
>  #include "json_writer.h"
>  #include "main.h"
> +#include "xlated_dumper.h"
>  
>  static struct hashmap *link_table;
> +static struct dump_data dd = {};
>  
>  static int link_parse_fd(int *argc, char ***argv)
>  {
> @@ -166,6 +168,45 @@ static int get_prog_info(int prog_id, struct bpf_prog_info *info)
>  	return err;
>  }
>  
> +static int cmp_u64(const void *A, const void *B)
> +{
> +	const __u64 *a = A, *b = B;
> +
> +	return *a - *b;
> +}
> +
> +static void
> +show_kprobe_multi_json(struct bpf_link_info *info, json_writer_t *wtr)
> +{
> +	__u32 i, j = 0;
> +	__u64 *addrs;
> +
> +	jsonw_bool_field(json_wtr, "retprobe",
> +			 info->kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN);
> +	jsonw_uint_field(json_wtr, "func_cnt", info->kprobe_multi.count);
> +	jsonw_name(json_wtr, "funcs");
> +	jsonw_start_array(json_wtr);
> +	addrs = (__u64 *)u64_to_ptr(info->kprobe_multi.addrs);
> +	qsort((void *)addrs, info->kprobe_multi.count, sizeof(__u64), cmp_u64);
> +
> +	/* Load it once for all. */
> +	if (!dd.sym_count)
> +		kernel_syms_load(&dd);
> +	for (i = 0; i < dd.sym_count; i++) {
> +		if (dd.sym_mapping[i].address != addrs[j])
> +			continue;
> +		jsonw_start_object(json_wtr);
> +		jsonw_uint_field(json_wtr, "addr", dd.sym_mapping[i].address);
> +		jsonw_string_field(json_wtr, "func", dd.sym_mapping[i].name);
> +		/* Print none if it is vmlinux */
> +		jsonw_string_field(json_wtr, "module", dd.sym_mapping[i].module);

We could maybe print null ("jsonw_null(json_wtr);") instead of an empty
string here when we have no module name. Although I'm not sure it
matters too much. Let's see whether the series needs another respin.

Anyway:

Reviewed-by: Quentin Monnet <quentin@isovalent.com>

Yafang Shao June 25, 2023, 2:29 p.m. UTC | #2

On Sat, Jun 24, 2023 at 12:49 AM Quentin Monnet <quentin@isovalent.com> wrote:
>
> 2023-06-23 14:15 UTC+0000 ~ Yafang Shao <laoar.shao@gmail.com>
> > Show the already expose kprobe_multi link info in bpftool. The result as
> > follows,
> >
> > $ tools/bpf/bpftool/bpftool link show
> > 4: kprobe_multi  prog 22
> >         kprobe.multi  func_cnt 7
> >         addr             func [module]
> >         ffffffffbbc44f20 schedule_timeout_interruptible
> >         ffffffffbbc44f60 schedule_timeout_killable
> >         ffffffffbbc44fa0 schedule_timeout_uninterruptible
> >         ffffffffbbc44fe0 schedule_timeout_idle
> >         ffffffffc08028d0 xfs_trans_get_efd [xfs]
> >         ffffffffc080fa10 xfs_trans_get_buf_map [xfs]
> >         ffffffffc0813320 xfs_trans_get_dqtrx [xfs]
> >         pids kprobe_multi(1434978)
> > 5: kprobe_multi  prog 22
> >         kretprobe.multi  func_cnt 7
> >         addr             func [module]
> >         ffffffffbbc44f20 schedule_timeout_interruptible
> >         ffffffffbbc44f60 schedule_timeout_killable
> >         ffffffffbbc44fa0 schedule_timeout_uninterruptible
> >         ffffffffbbc44fe0 schedule_timeout_idle
> >         ffffffffc08028d0 xfs_trans_get_efd [xfs]
> >         ffffffffc080fa10 xfs_trans_get_buf_map [xfs]
> >         ffffffffc0813320 xfs_trans_get_dqtrx [xfs]
> >         pids kprobe_multi(1434978)
> >
> > $ tools/bpf/bpftool/bpftool link show -j
> > [{"id":4,"type":"kprobe_multi","prog_id":22,"retprobe":false,"func_cnt":7,"funcs":[{"addr":18446744072564789024,"func":"schedule_timeout_interruptible","module":""},{"addr":18446744072564789088,"func":"schedule_timeout_killable","module":""},{"addr":18446744072564789152,"func":"schedule_timeout_uninterruptible","module":""},{"addr":18446744072564789216,"func":"schedule_timeout_idle","module":""},{"addr":18446744072644208848,"func":"xfs_trans_get_efd","module":"xfs"},{"addr":18446744072644262416,"func":"xfs_trans_get_buf_map","module":"xfs"},{"addr":18446744072644277024,"func":"xfs_trans_get_dqtrx","module":"xfs"}],"pids":[{"pid":1434978,"comm":"kprobe_multi"}]},{"id":5,"type":"kprobe_multi","prog_id":22,"retprobe":true,"func_cnt":7,"funcs":[{"addr":18446744072564789024,"func":"schedule_timeout_interruptible","module":""},{"addr":18446744072564789088,"func":"schedule_timeout_killable","module":""},{"addr":18446744072564789152,"func":"schedule_timeout_uninterruptible","module":""},{"addr":18446744072564789216,"func":"schedule_timeout_idle","module":""},{"addr":18446744072644208848,"func":"xfs_trans_get_efd","module":"xfs"},{"addr":18446744072644262416,"func":"xfs_trans_get_buf_map","module":"xfs"},{"addr":18446744072644277024,"func":"xfs_trans_get_dqtrx","module":"xfs"}],"pids":[{"pid":1434978,"comm":"kprobe_multi"}]}]
> >
> > When kptr_restrict is 2, the result is,
> >
> > $ tools/bpf/bpftool/bpftool link show
> > 4: kprobe_multi  prog 22
> >         kprobe.multi  func_cnt 7
> > 5: kprobe_multi  prog 22
> >         kretprobe.multi  func_cnt 7
> >
> > Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
> > ---
> >  tools/bpf/bpftool/link.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 108 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
> > index 2d78607..8461e6d 100644
> > --- a/tools/bpf/bpftool/link.c
> > +++ b/tools/bpf/bpftool/link.c
> > @@ -14,8 +14,10 @@
> >
> >  #include "json_writer.h"
> >  #include "main.h"
> > +#include "xlated_dumper.h"
> >
> >  static struct hashmap *link_table;
> > +static struct dump_data dd = {};
> >
> >  static int link_parse_fd(int *argc, char ***argv)
> >  {
> > @@ -166,6 +168,45 @@ static int get_prog_info(int prog_id, struct bpf_prog_info *info)
> >       return err;
> >  }
> >
> > +static int cmp_u64(const void *A, const void *B)
> > +{
> > +     const __u64 *a = A, *b = B;
> > +
> > +     return *a - *b;
> > +}
> > +
> > +static void
> > +show_kprobe_multi_json(struct bpf_link_info *info, json_writer_t *wtr)
> > +{
> > +     __u32 i, j = 0;
> > +     __u64 *addrs;
> > +
> > +     jsonw_bool_field(json_wtr, "retprobe",
> > +                      info->kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN);
> > +     jsonw_uint_field(json_wtr, "func_cnt", info->kprobe_multi.count);
> > +     jsonw_name(json_wtr, "funcs");
> > +     jsonw_start_array(json_wtr);
> > +     addrs = (__u64 *)u64_to_ptr(info->kprobe_multi.addrs);
> > +     qsort((void *)addrs, info->kprobe_multi.count, sizeof(__u64), cmp_u64);
> > +
> > +     /* Load it once for all. */
> > +     if (!dd.sym_count)
> > +             kernel_syms_load(&dd);
> > +     for (i = 0; i < dd.sym_count; i++) {
> > +             if (dd.sym_mapping[i].address != addrs[j])
> > +                     continue;
> > +             jsonw_start_object(json_wtr);
> > +             jsonw_uint_field(json_wtr, "addr", dd.sym_mapping[i].address);
> > +             jsonw_string_field(json_wtr, "func", dd.sym_mapping[i].name);
> > +             /* Print none if it is vmlinux */
> > +             jsonw_string_field(json_wtr, "module", dd.sym_mapping[i].module);
>
> We could maybe print null ("jsonw_null(json_wtr);") instead of an empty
> string here when we have no module name. Although I'm not sure it
> matters too much. Let's see whether the series needs another respin.

Will change it. Thanks for your review.

>
> Anyway:
>
> Reviewed-by: Quentin Monnet <quentin@isovalent.com>

diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
index 2d78607..8461e6d 100644
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c
@@ -14,8 +14,10 @@ 
 
 #include "json_writer.h"
 #include "main.h"
+#include "xlated_dumper.h"
 
 static struct hashmap *link_table;
+static struct dump_data dd = {};
 
 static int link_parse_fd(int *argc, char ***argv)
 {
@@ -166,6 +168,45 @@  static int get_prog_info(int prog_id, struct bpf_prog_info *info)
 	return err;
 }
 
+static int cmp_u64(const void *A, const void *B)
+{
+	const __u64 *a = A, *b = B;
+
+	return *a - *b;
+}
+
+static void
+show_kprobe_multi_json(struct bpf_link_info *info, json_writer_t *wtr)
+{
+	__u32 i, j = 0;
+	__u64 *addrs;
+
+	jsonw_bool_field(json_wtr, "retprobe",
+			 info->kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN);
+	jsonw_uint_field(json_wtr, "func_cnt", info->kprobe_multi.count);
+	jsonw_name(json_wtr, "funcs");
+	jsonw_start_array(json_wtr);
+	addrs = (__u64 *)u64_to_ptr(info->kprobe_multi.addrs);
+	qsort((void *)addrs, info->kprobe_multi.count, sizeof(__u64), cmp_u64);
+
+	/* Load it once for all. */
+	if (!dd.sym_count)
+		kernel_syms_load(&dd);
+	for (i = 0; i < dd.sym_count; i++) {
+		if (dd.sym_mapping[i].address != addrs[j])
+			continue;
+		jsonw_start_object(json_wtr);
+		jsonw_uint_field(json_wtr, "addr", dd.sym_mapping[i].address);
+		jsonw_string_field(json_wtr, "func", dd.sym_mapping[i].name);
+		/* Print none if it is vmlinux */
+		jsonw_string_field(json_wtr, "module", dd.sym_mapping[i].module);
+		jsonw_end_object(json_wtr);
+		if (j++ == info->kprobe_multi.count)
+			break;
+	}
+	jsonw_end_array(json_wtr);
+}
+
 static int show_link_close_json(int fd, struct bpf_link_info *info)
 {
 	struct bpf_prog_info prog_info;
@@ -218,6 +259,9 @@  static int show_link_close_json(int fd, struct bpf_link_info *info)
 		jsonw_uint_field(json_wtr, "map_id",
 				 info->struct_ops.map_id);
 		break;
+	case BPF_LINK_TYPE_KPROBE_MULTI:
+		show_kprobe_multi_json(info, json_wtr);
+		break;
 	default:
 		break;
 	}
@@ -351,6 +395,44 @@  void netfilter_dump_plain(const struct bpf_link_info *info)
 		printf(" flags 0x%x", info->netfilter.flags);
 }
 
+static void show_kprobe_multi_plain(struct bpf_link_info *info)
+{
+	__u32 i, j = 0;
+	__u64 *addrs;
+
+	if (!info->kprobe_multi.count)
+		return;
+
+	if (info->kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN)
+		printf("\n\tkretprobe.multi  ");
+	else
+		printf("\n\tkprobe.multi  ");
+	printf("func_cnt %u  ", info->kprobe_multi.count);
+	addrs = (__u64 *)u64_to_ptr(info->kprobe_multi.addrs);
+	qsort((void *)addrs, info->kprobe_multi.count, sizeof(__u64), cmp_u64);
+
+	/* Load it once for all. */
+	if (!dd.sym_count)
+		kernel_syms_load(&dd);
+	if (!dd.sym_count)
+		return;
+
+	printf("\n\t%-16s %s", "addr", "func [module]");
+	for (i = 0; i < dd.sym_count; i++) {
+		if (dd.sym_mapping[i].address != addrs[j])
+			continue;
+		printf("\n\t%016lx %s",
+		       dd.sym_mapping[i].address, dd.sym_mapping[i].name);
+		if (dd.sym_mapping[i].module[0] != '\0')
+			printf(" [%s]  ", dd.sym_mapping[i].module);
+		else
+			printf("  ");
+
+		if (j++ == info->kprobe_multi.count)
+			break;
+	}
+}
+
 static int show_link_close_plain(int fd, struct bpf_link_info *info)
 {
 	struct bpf_prog_info prog_info;
@@ -396,6 +478,9 @@  static int show_link_close_plain(int fd, struct bpf_link_info *info)
 	case BPF_LINK_TYPE_NETFILTER:
 		netfilter_dump_plain(info);
 		break;
+	case BPF_LINK_TYPE_KPROBE_MULTI:
+		show_kprobe_multi_plain(info);
+		break;
 	default:
 		break;
 	}
@@ -417,7 +502,9 @@  static int do_show_link(int fd)
 {
 	struct bpf_link_info info;
 	__u32 len = sizeof(info);
+	__u64 *addrs = NULL;
 	char buf[256];
+	int count;
 	int err;
 
 	memset(&info, 0, sizeof(info));
@@ -441,12 +528,28 @@  static int do_show_link(int fd)
 		info.iter.target_name_len = sizeof(buf);
 		goto again;
 	}
+	if (info.type == BPF_LINK_TYPE_KPROBE_MULTI &&
+	    !info.kprobe_multi.addrs) {
+		count = info.kprobe_multi.count;
+		if (count) {
+			addrs = calloc(count, sizeof(__u64));
+			if (!addrs) {
+				p_err("mem alloc failed");
+				close(fd);
+				return -1;
+			}
+			info.kprobe_multi.addrs = (unsigned long)addrs;
+			goto again;
+		}
+	}
 
 	if (json_output)
 		show_link_close_json(fd, &info);
 	else
 		show_link_close_plain(fd, &info);
 
+	if (addrs)
+		free(addrs);
 	close(fd);
 	return 0;
 }
@@ -471,7 +574,8 @@  static int do_show(int argc, char **argv)
 		fd = link_parse_fd(&argc, &argv);
 		if (fd < 0)
 			return fd;
-		return do_show_link(fd);
+		do_show_link(fd);
+		goto out;
 	}
 
 	if (argc)
@@ -510,6 +614,9 @@  static int do_show(int argc, char **argv)
 	if (show_pinned)
 		delete_pinned_obj_table(link_table);
 
+out:
+	if (dd.sym_count)
+		kernel_syms_destroy(&dd);
 	return errno == ENOENT ? 0 : -1;
 }

[v5,bpf-next,03/11] bpftool: Show kprobe_multi link info

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