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* [PATCH bpf-next v5 0/3] libbpf: use func name when pinning programs with LIBBPF_STRICT_SEC_NAME
@ 2021-10-21 21:48 Stanislav Fomichev
  2021-10-21 21:48 ` [PATCH bpf-next v5 1/3] " Stanislav Fomichev
                   ` (3 more replies)
  0 siblings, 4 replies; 6+ messages in thread
From: Stanislav Fomichev @ 2021-10-21 21:48 UTC (permalink / raw)
  To: netdev, bpf; +Cc: ast, daniel, andrii, Stanislav Fomichev

Commit 15669e1dcd75 ("selftests/bpf: Normalize all the rest SEC() uses")
broke flow dissector tests. With the strict section names, bpftool isn't
able to pin all programs of the objects (all section names are the
same now). To bring it back to life let's do the following:

- teach libbpf to pin by func name with LIBBPF_STRICT_SEC_NAME
- enable strict mode in bpftool (breaking cli change)
- fix custom flow_dissector loader to use strict mode
- fix flow_dissector tests to use new pin names (func vs sec)

v5:
- get rid of error when retrying with '/' (Quentin Monnet)

v4:
- fix comment spelling (Quentin Monnet)
- retry progtype without / (Quentin Monnet)

v3:
- clarify program pinning in LIBBPF_STRICT_SEC_NAME,
  for real this time (Andrii Nakryiko)
- fix possible segfault in __bpf_program__pin_name (Andrii Nakryiko)

v2:
- add github issue (Andrii Nakryiko)
- remove sec_name from bpf_program.pin_name comment (Andrii Nakryiko)
- add cover letter (Andrii Nakryiko)

Stanislav Fomichev (3):
  libbpf: use func name when pinning programs with
    LIBBPF_STRICT_SEC_NAME
  bpftool: conditionally append / to the progtype
  selftests/bpf: fix flow dissector tests

 tools/bpf/bpftool/main.c                      |  4 +++
 tools/bpf/bpftool/prog.c                      | 35 ++++++++++---------
 tools/lib/bpf/libbpf.c                        | 13 +++++--
 tools/lib/bpf/libbpf_legacy.h                 |  3 ++
 .../selftests/bpf/flow_dissector_load.c       | 18 ++++++----
 .../selftests/bpf/flow_dissector_load.h       | 10 ++----
 .../selftests/bpf/test_flow_dissector.sh      | 10 +++---
 7 files changed, 55 insertions(+), 38 deletions(-)

-- 
2.33.0.1079.g6e70778dc9-goog


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH bpf-next v5 1/3] libbpf: use func name when pinning programs with LIBBPF_STRICT_SEC_NAME
  2021-10-21 21:48 [PATCH bpf-next v5 0/3] libbpf: use func name when pinning programs with LIBBPF_STRICT_SEC_NAME Stanislav Fomichev
@ 2021-10-21 21:48 ` Stanislav Fomichev
  2021-10-21 21:48 ` [PATCH bpf-next v5 2/3] bpftool: conditionally append / to the progtype Stanislav Fomichev
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 6+ messages in thread
From: Stanislav Fomichev @ 2021-10-21 21:48 UTC (permalink / raw)
  To: netdev, bpf; +Cc: ast, daniel, andrii, Stanislav Fomichev, Quentin Monnet

We can't use section name anymore because they are not unique
and pinning objects with multiple programs with the same
progtype/secname will fail.

Closes: https://github.com/libbpf/libbpf/issues/273
Fixes: 33a2c75c55e2 ("libbpf: add internal pin_name")
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 tools/lib/bpf/libbpf.c        | 13 +++++++++++--
 tools/lib/bpf/libbpf_legacy.h |  3 +++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 760c7e346603..7f48eeb3ca82 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -285,7 +285,7 @@ struct bpf_program {
 	size_t sub_insn_off;
 
 	char *name;
-	/* sec_name with / replaced by _; makes recursive pinning
+	/* name with / replaced by _; makes recursive pinning
 	 * in bpf_object__pin_programs easier
 	 */
 	char *pin_name;
@@ -614,7 +614,16 @@ static char *__bpf_program__pin_name(struct bpf_program *prog)
 {
 	char *name, *p;
 
-	name = p = strdup(prog->sec_name);
+	if (libbpf_mode & LIBBPF_STRICT_SEC_NAME)
+		name = strdup(prog->name);
+	else
+		name = strdup(prog->sec_name);
+
+	if (!name)
+		return NULL;
+
+	p = name;
+
 	while ((p = strchr(p, '/')))
 		*p = '_';
 
diff --git a/tools/lib/bpf/libbpf_legacy.h b/tools/lib/bpf/libbpf_legacy.h
index 74e6f860f703..29ccafab11a8 100644
--- a/tools/lib/bpf/libbpf_legacy.h
+++ b/tools/lib/bpf/libbpf_legacy.h
@@ -52,6 +52,9 @@ enum libbpf_strict_mode {
 	 * allowed, with LIBBPF_STRICT_SEC_PREFIX this will become
 	 * unrecognized by libbpf and would have to be just SEC("xdp") and
 	 * SEC("xdp") and SEC("perf_event").
+	 *
+	 * Note, in this mode the program pin path will be based on the
+	 * function name instead of section name.
 	 */
 	LIBBPF_STRICT_SEC_NAME = 0x04,
 
-- 
2.33.0.1079.g6e70778dc9-goog


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH bpf-next v5 2/3] bpftool: conditionally append / to the progtype
  2021-10-21 21:48 [PATCH bpf-next v5 0/3] libbpf: use func name when pinning programs with LIBBPF_STRICT_SEC_NAME Stanislav Fomichev
  2021-10-21 21:48 ` [PATCH bpf-next v5 1/3] " Stanislav Fomichev
@ 2021-10-21 21:48 ` Stanislav Fomichev
  2021-10-22  8:20   ` Quentin Monnet
  2021-10-21 21:48 ` [PATCH bpf-next v5 3/3] selftests/bpf: fix flow dissector tests Stanislav Fomichev
  2021-10-22 23:57 ` [PATCH bpf-next v5 0/3] libbpf: use func name when pinning programs with LIBBPF_STRICT_SEC_NAME Andrii Nakryiko
  3 siblings, 1 reply; 6+ messages in thread
From: Stanislav Fomichev @ 2021-10-21 21:48 UTC (permalink / raw)
  To: netdev, bpf; +Cc: ast, daniel, andrii, Stanislav Fomichev, Quentin Monnet

Otherwise, attaching with bpftool doesn't work with strict section names.

Also, switch to libbpf strict mode to use the latest conventions
(note, I don't think we have any cli api guarantees?).

Cc: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 tools/bpf/bpftool/main.c |  4 ++++
 tools/bpf/bpftool/prog.c | 35 +++++++++++++++++++----------------
 2 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index 02eaaf065f65..8223bac1e401 100644
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -409,6 +409,10 @@ int main(int argc, char **argv)
 	block_mount = false;
 	bin_name = argv[0];
 
+	ret = libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
+	if (ret)
+		p_err("failed to enable libbpf strict mode: %d", ret);
+
 	hash_init(prog_table.table);
 	hash_init(map_table.table);
 	hash_init(link_table.table);
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 277d51c4c5d9..6fec425d5390 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -1396,8 +1396,6 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
 
 	while (argc) {
 		if (is_prefix(*argv, "type")) {
-			char *type;
-
 			NEXT_ARG();
 
 			if (common_prog_type != BPF_PROG_TYPE_UNSPEC) {
@@ -1407,21 +1405,26 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
 			if (!REQ_ARGS(1))
 				goto err_free_reuse_maps;
 
-			/* Put a '/' at the end of type to appease libbpf */
-			type = malloc(strlen(*argv) + 2);
-			if (!type) {
-				p_err("mem alloc failed");
-				goto err_free_reuse_maps;
-			}
-			*type = 0;
-			strcat(type, *argv);
-			strcat(type, "/");
+			err = libbpf_prog_type_by_name(*argv, &common_prog_type,
+						       &expected_attach_type);
+			if (err < 0) {
+				/* Put a '/' at the end of type to appease libbpf */
+				char *type = malloc(strlen(*argv) + 2);
 
-			err = get_prog_type_by_name(type, &common_prog_type,
-						    &expected_attach_type);
-			free(type);
-			if (err < 0)
-				goto err_free_reuse_maps;
+				if (!type) {
+					p_err("mem alloc failed");
+					goto err_free_reuse_maps;
+				}
+				*type = 0;
+				strcat(type, *argv);
+				strcat(type, "/");
+
+				err = get_prog_type_by_name(type, &common_prog_type,
+							    &expected_attach_type);
+				free(type);
+				if (err < 0)
+					goto err_free_reuse_maps;
+			}
 
 			NEXT_ARG();
 		} else if (is_prefix(*argv, "map")) {
-- 
2.33.0.1079.g6e70778dc9-goog


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH bpf-next v5 3/3] selftests/bpf: fix flow dissector tests
  2021-10-21 21:48 [PATCH bpf-next v5 0/3] libbpf: use func name when pinning programs with LIBBPF_STRICT_SEC_NAME Stanislav Fomichev
  2021-10-21 21:48 ` [PATCH bpf-next v5 1/3] " Stanislav Fomichev
  2021-10-21 21:48 ` [PATCH bpf-next v5 2/3] bpftool: conditionally append / to the progtype Stanislav Fomichev
@ 2021-10-21 21:48 ` Stanislav Fomichev
  2021-10-22 23:57 ` [PATCH bpf-next v5 0/3] libbpf: use func name when pinning programs with LIBBPF_STRICT_SEC_NAME Andrii Nakryiko
  3 siblings, 0 replies; 6+ messages in thread
From: Stanislav Fomichev @ 2021-10-21 21:48 UTC (permalink / raw)
  To: netdev, bpf; +Cc: ast, daniel, andrii, Stanislav Fomichev

- update custom loader to search by name, not section name
- update bpftool commands to use proper pin path

Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 .../selftests/bpf/flow_dissector_load.c        | 18 +++++++++++-------
 .../selftests/bpf/flow_dissector_load.h        | 10 ++--------
 .../selftests/bpf/test_flow_dissector.sh       | 10 +++++-----
 3 files changed, 18 insertions(+), 20 deletions(-)

diff --git a/tools/testing/selftests/bpf/flow_dissector_load.c b/tools/testing/selftests/bpf/flow_dissector_load.c
index 3fd83b9dc1bf..87fd1aa323a9 100644
--- a/tools/testing/selftests/bpf/flow_dissector_load.c
+++ b/tools/testing/selftests/bpf/flow_dissector_load.c
@@ -17,7 +17,7 @@
 const char *cfg_pin_path = "/sys/fs/bpf/flow_dissector";
 const char *cfg_map_name = "jmp_table";
 bool cfg_attach = true;
-char *cfg_section_name;
+char *cfg_prog_name;
 char *cfg_path_name;
 
 static void load_and_attach_program(void)
@@ -25,7 +25,11 @@ static void load_and_attach_program(void)
 	int prog_fd, ret;
 	struct bpf_object *obj;
 
-	ret = bpf_flow_load(&obj, cfg_path_name, cfg_section_name,
+	ret = libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
+	if (ret)
+		error(1, 0, "failed to enable libbpf strict mode: %d", ret);
+
+	ret = bpf_flow_load(&obj, cfg_path_name, cfg_prog_name,
 			    cfg_map_name, NULL, &prog_fd, NULL);
 	if (ret)
 		error(1, 0, "bpf_flow_load %s", cfg_path_name);
@@ -75,15 +79,15 @@ static void parse_opts(int argc, char **argv)
 			break;
 		case 'p':
 			if (cfg_path_name)
-				error(1, 0, "only one prog name can be given");
+				error(1, 0, "only one path can be given");
 
 			cfg_path_name = optarg;
 			break;
 		case 's':
-			if (cfg_section_name)
-				error(1, 0, "only one section can be given");
+			if (cfg_prog_name)
+				error(1, 0, "only one prog can be given");
 
-			cfg_section_name = optarg;
+			cfg_prog_name = optarg;
 			break;
 		}
 	}
@@ -94,7 +98,7 @@ static void parse_opts(int argc, char **argv)
 	if (cfg_attach && !cfg_path_name)
 		error(1, 0, "must provide a path to the BPF program");
 
-	if (cfg_attach && !cfg_section_name)
+	if (cfg_attach && !cfg_prog_name)
 		error(1, 0, "must provide a section name");
 }
 
diff --git a/tools/testing/selftests/bpf/flow_dissector_load.h b/tools/testing/selftests/bpf/flow_dissector_load.h
index 7290401ec172..9d0acc2fc6cc 100644
--- a/tools/testing/selftests/bpf/flow_dissector_load.h
+++ b/tools/testing/selftests/bpf/flow_dissector_load.h
@@ -7,7 +7,7 @@
 
 static inline int bpf_flow_load(struct bpf_object **obj,
 				const char *path,
-				const char *section_name,
+				const char *prog_name,
 				const char *map_name,
 				const char *keys_map_name,
 				int *prog_fd,
@@ -23,13 +23,7 @@ static inline int bpf_flow_load(struct bpf_object **obj,
 	if (ret)
 		return ret;
 
-	main_prog = NULL;
-	bpf_object__for_each_program(prog, *obj) {
-		if (strcmp(section_name, bpf_program__section_name(prog)) == 0) {
-			main_prog = prog;
-			break;
-		}
-	}
+	main_prog = bpf_object__find_program_by_name(*obj, prog_name);
 	if (!main_prog)
 		return -1;
 
diff --git a/tools/testing/selftests/bpf/test_flow_dissector.sh b/tools/testing/selftests/bpf/test_flow_dissector.sh
index 174b72a64a4c..dbd91221727d 100755
--- a/tools/testing/selftests/bpf/test_flow_dissector.sh
+++ b/tools/testing/selftests/bpf/test_flow_dissector.sh
@@ -26,22 +26,22 @@ if [[ -z $(ip netns identify $$) ]]; then
 			type flow_dissector
 
 		if ! unshare --net $bpftool prog attach pinned \
-			/sys/fs/bpf/flow/flow_dissector flow_dissector; then
+			/sys/fs/bpf/flow/_dissect flow_dissector; then
 			echo "Unexpected unsuccessful attach in namespace" >&2
 			err=1
 		fi
 
-		$bpftool prog attach pinned /sys/fs/bpf/flow/flow_dissector \
+		$bpftool prog attach pinned /sys/fs/bpf/flow/_dissect \
 			flow_dissector
 
 		if unshare --net $bpftool prog attach pinned \
-			/sys/fs/bpf/flow/flow_dissector flow_dissector; then
+			/sys/fs/bpf/flow/_dissect flow_dissector; then
 			echo "Unexpected successful attach in namespace" >&2
 			err=1
 		fi
 
 		if ! $bpftool prog detach pinned \
-			/sys/fs/bpf/flow/flow_dissector flow_dissector; then
+			/sys/fs/bpf/flow/_dissect flow_dissector; then
 			echo "Failed to detach flow dissector" >&2
 			err=1
 		fi
@@ -95,7 +95,7 @@ else
 fi
 
 # Attach BPF program
-./flow_dissector_load -p bpf_flow.o -s flow_dissector
+./flow_dissector_load -p bpf_flow.o -s _dissect
 
 # Setup
 tc qdisc add dev lo ingress
-- 
2.33.0.1079.g6e70778dc9-goog


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH bpf-next v5 2/3] bpftool: conditionally append / to the progtype
  2021-10-21 21:48 ` [PATCH bpf-next v5 2/3] bpftool: conditionally append / to the progtype Stanislav Fomichev
@ 2021-10-22  8:20   ` Quentin Monnet
  0 siblings, 0 replies; 6+ messages in thread
From: Quentin Monnet @ 2021-10-22  8:20 UTC (permalink / raw)
  To: Stanislav Fomichev, netdev, bpf; +Cc: ast, daniel, andrii

2021-10-21 14:48 UTC-0700 ~ Stanislav Fomichev <sdf@google.com>
> Otherwise, attaching with bpftool doesn't work with strict section names.
> 
> Also, switch to libbpf strict mode to use the latest conventions
> (note, I don't think we have any cli api guarantees?).
> 
> Cc: Quentin Monnet <quentin@isovalent.com>
> Signed-off-by: Stanislav Fomichev <sdf@google.com>

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

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH bpf-next v5 0/3] libbpf: use func name when pinning programs with LIBBPF_STRICT_SEC_NAME
  2021-10-21 21:48 [PATCH bpf-next v5 0/3] libbpf: use func name when pinning programs with LIBBPF_STRICT_SEC_NAME Stanislav Fomichev
                   ` (2 preceding siblings ...)
  2021-10-21 21:48 ` [PATCH bpf-next v5 3/3] selftests/bpf: fix flow dissector tests Stanislav Fomichev
@ 2021-10-22 23:57 ` Andrii Nakryiko
  3 siblings, 0 replies; 6+ messages in thread
From: Andrii Nakryiko @ 2021-10-22 23:57 UTC (permalink / raw)
  To: Stanislav Fomichev
  Cc: Networking, bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko

On Thu, Oct 21, 2021 at 2:48 PM Stanislav Fomichev <sdf@google.com> wrote:
>
> Commit 15669e1dcd75 ("selftests/bpf: Normalize all the rest SEC() uses")
> broke flow dissector tests. With the strict section names, bpftool isn't
> able to pin all programs of the objects (all section names are the
> same now). To bring it back to life let's do the following:
>
> - teach libbpf to pin by func name with LIBBPF_STRICT_SEC_NAME
> - enable strict mode in bpftool (breaking cli change)
> - fix custom flow_dissector loader to use strict mode
> - fix flow_dissector tests to use new pin names (func vs sec)
>
> v5:
> - get rid of error when retrying with '/' (Quentin Monnet)
>
> v4:
> - fix comment spelling (Quentin Monnet)
> - retry progtype without / (Quentin Monnet)
>
> v3:
> - clarify program pinning in LIBBPF_STRICT_SEC_NAME,
>   for real this time (Andrii Nakryiko)
> - fix possible segfault in __bpf_program__pin_name (Andrii Nakryiko)
>
> v2:
> - add github issue (Andrii Nakryiko)
> - remove sec_name from bpf_program.pin_name comment (Andrii Nakryiko)
> - add cover letter (Andrii Nakryiko)
>
> Stanislav Fomichev (3):
>   libbpf: use func name when pinning programs with
>     LIBBPF_STRICT_SEC_NAME
>   bpftool: conditionally append / to the progtype
>   selftests/bpf: fix flow dissector tests

I've applied patches #1 and #3, as they have to happen regardless of
how bpftool incompatibility is going to be handled. Please see
comments from John about bpftool. I think we should try to preserve
bpftool's backwards compatibility, or at the very least give users
some way to fall back to non-strict mode during the transition period.
I trust you, John and Quentin will figure out the best way forward
there.

Also, please move this flow_dissector_load selftest into test_progs,
so that we exercise it regularly.

>
>  tools/bpf/bpftool/main.c                      |  4 +++
>  tools/bpf/bpftool/prog.c                      | 35 ++++++++++---------
>  tools/lib/bpf/libbpf.c                        | 13 +++++--
>  tools/lib/bpf/libbpf_legacy.h                 |  3 ++
>  .../selftests/bpf/flow_dissector_load.c       | 18 ++++++----
>  .../selftests/bpf/flow_dissector_load.h       | 10 ++----
>  .../selftests/bpf/test_flow_dissector.sh      | 10 +++---
>  7 files changed, 55 insertions(+), 38 deletions(-)
>
> --
> 2.33.0.1079.g6e70778dc9-goog
>

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2021-10-22 23:57 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-10-21 21:48 [PATCH bpf-next v5 0/3] libbpf: use func name when pinning programs with LIBBPF_STRICT_SEC_NAME Stanislav Fomichev
2021-10-21 21:48 ` [PATCH bpf-next v5 1/3] " Stanislav Fomichev
2021-10-21 21:48 ` [PATCH bpf-next v5 2/3] bpftool: conditionally append / to the progtype Stanislav Fomichev
2021-10-22  8:20   ` Quentin Monnet
2021-10-21 21:48 ` [PATCH bpf-next v5 3/3] selftests/bpf: fix flow dissector tests Stanislav Fomichev
2021-10-22 23:57 ` [PATCH bpf-next v5 0/3] libbpf: use func name when pinning programs with LIBBPF_STRICT_SEC_NAME Andrii Nakryiko

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