Patch "libbpf: Fix removal of inner map in bpf_object__create_map" has been added to the 5.14-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    libbpf: Fix removal of inner map in bpf_object__create_map

to the 5.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     libbpf-fix-removal-of-inner-map-in-bpf_object__creat.patch
and it can be found in the queue-5.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 12ed1362c5f8d83773c701843e8eedc19d140e95
Author: Martynas Pumputis <m@xxxxxxxxx>
Date:   Mon Jul 19 19:38:37 2021 +0200

    libbpf: Fix removal of inner map in bpf_object__create_map
    
    [ Upstream commit a21ab4c59e09c2a9994a6e393b7484e3b3f78a99 ]
    
    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@xxxxxxxxxx>
    Signed-off-by: Martynas Pumputis <m@xxxxxxxxx>
    Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
    Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
    Link: https://lore.kernel.org/bpf/20210719173838.423148-2-m@xxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 1bfd11de9be6..aa5ad6fc5f40 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",
@@ -4547,8 +4546,8 @@ 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",
 			map->name, cp, err);
@@ -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)