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From: Martynas Pumputis <m@lambda.lt>
To: bpf@vger.kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, m@lambda.lt
Subject: [PATCH bpf 1/2] libbpf: fix removal of inner map in bpf_object__create_map
Date: Mon, 19 Jul 2021 19:38:37 +0200	[thread overview]
Message-ID: <20210719173838.423148-2-m@lambda.lt> (raw)
In-Reply-To: <20210719173838.423148-1-m@lambda.lt>

If creating an outer map of a BTF-defined map-in-map fails (via
bpf_object__create_map()), then the previously created its inner map
won't be destroyed.

Fix this by ensuring that the destroy routines are not bypassed in the
case of a failure.

Fixes: 646f02ffdd49c ("libbpf: Add BTF-defined map-in-map support")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Martynas Pumputis <m@lambda.lt>
---
 tools/lib/bpf/libbpf.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 6f5e2757bb3c..dde521366579 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4479,6 +4479,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b
 {
 	struct bpf_create_map_attr create_attr;
 	struct bpf_map_def *def = &map->def;
+	int err = 0;
 
 	memset(&create_attr, 0, sizeof(create_attr));
 
@@ -4521,8 +4522,6 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b
 
 	if (bpf_map_type__is_map_in_map(def->type)) {
 		if (map->inner_map) {
-			int err;
-
 			err = bpf_object__create_map(obj, map->inner_map, true);
 			if (err) {
 				pr_warn("map '%s': failed to create inner map: %d\n",
@@ -4547,7 +4546,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b
 	if (map->fd < 0 && (create_attr.btf_key_type_id ||
 			    create_attr.btf_value_type_id)) {
 		char *cp, errmsg[STRERR_BUFSIZE];
-		int err = -errno;
+		err = -errno;
 
 		cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
 		pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
@@ -4560,8 +4559,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b
 		map->fd = bpf_create_map_xattr(&create_attr);
 	}
 
-	if (map->fd < 0)
-		return -errno;
+	err = map->fd < 0 ? -errno : 0;
 
 	if (bpf_map_type__is_map_in_map(def->type) && map->inner_map) {
 		if (obj->gen_loader)
@@ -4570,7 +4568,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b
 		zfree(&map->inner_map);
 	}
 
-	return 0;
+	return err;
 }
 
 static int init_map_slots(struct bpf_object *obj, struct bpf_map *map)
-- 
2.32.0


  reply	other threads:[~2021-07-19 17:39 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-19 17:38 [PATCH v2 bpf 0/2] libbpf: fix inner map removal in bpf_object__create_map Martynas Pumputis
2021-07-19 17:38 ` Martynas Pumputis [this message]
2021-07-19 22:58   ` [PATCH bpf 1/2] libbpf: fix removal of inner map " Andrii Nakryiko
2021-07-19 17:38 ` [PATCH bpf 2/2] selftests/bpf: check inner map deletion Martynas Pumputis
2021-07-19 22:59   ` Andrii Nakryiko
2021-07-20 20:24   ` Andrii Nakryiko
  -- strict thread matches above, loose matches on Subject: below --
2021-07-14 16:54 [PATCH bpf 0/2] libbpf: fix inner map removal in bpf_object__create_map Martynas Pumputis
2021-07-14 16:54 ` [PATCH bpf 1/2] libbpf: fix removal of inner map " Martynas Pumputis
2021-07-15  0:30   ` John Fastabend
2021-07-15 10:06     ` Martynas Pumputis
2021-07-15 19:59       ` John Fastabend
2021-07-16  3:06         ` John Fastabend
2021-07-16  3:09   ` John Fastabend
2021-07-16  5:27   ` Andrii Nakryiko
2021-07-16 15:24     ` Martynas Pumputis

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