On Wed, Jul 14, 2021 at 9:52 AM Martynas Pumputis <m@xxxxxxxxx> wrote:
>
> Add a test case to check whether an unsuccessful creation of an outer
> map of a BTF-defined map-in-map destroys the inner map.
>
> As bpf_object__create_map() is a static function, we cannot just call it
> from the test case and then check whether a map accessible via
> map->inner_map_fd has been removed. Instead, we iterate over all maps
> and check whether the map "$MAP_NAME.inner" does not exist.
>
> Signed-off-by: Martynas Pumputis <m@xxxxxxxxx>
> ---
> .../bpf/progs/test_map_in_map_invalid.c | 27 +++++++++
> tools/testing/selftests/bpf/test_maps.c | 58 ++++++++++++++++++-
> 2 files changed, 84 insertions(+), 1 deletion(-)
> create mode 100644 tools/testing/selftests/bpf/progs/test_map_in_map_invalid.c
>
> diff --git a/tools/testing/selftests/bpf/progs/test_map_in_map_invalid.c b/tools/testing/selftests/bpf/progs/test_map_in_map_invalid.c
> new file mode 100644
> index 000000000000..03601779e4ed
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/test_map_in_map_invalid.c
> @@ -0,0 +1,27 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2021 Isovalent, Inc. */
> +#include <linux/bpf.h>
> +#include <bpf/bpf_helpers.h>
> +
> +struct inner {
> + __uint(type, BPF_MAP_TYPE_ARRAY);
> + __type(key, __u32);
> + __type(value, int);
> + __uint(max_entries, 4);
> +};
> +
> +struct {
> + __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
> + __uint(max_entries, 0); /* This will make map creation to fail */
> + __uint(key_size, sizeof(__u32));
> + __array(values, struct inner);
> +} mim SEC(".maps");
> +
> +SEC("xdp_noop")
> +int xdp_noop0(struct xdp_md *ctx)
> +{
> + return XDP_PASS;
> +}
> +
> +int _version SEC("version") = 1;
please don't add new uses of version, it's completely unnecessary on
modern kernels
> +char _license[] SEC("license") = "GPL";
> diff --git a/tools/testing/selftests/bpf/test_maps.c b/tools/testing/selftests/bpf/test_maps.c
> index 30cbf5d98f7d..48f6c6dfd188 100644
> --- a/tools/testing/selftests/bpf/test_maps.c
> +++ b/tools/testing/selftests/bpf/test_maps.c
> @@ -1153,12 +1153,16 @@ static void test_sockmap(unsigned int tasks, void *data)
> }
>
> #define MAPINMAP_PROG "./test_map_in_map.o"
> +#define MAPINMAP_INVALID_PROG "./test_map_in_map_invalid.o"
> static void test_map_in_map(void)
> {
> struct bpf_object *obj;
> struct bpf_map *map;
> int mim_fd, fd, err;
> int pos = 0;
> + struct bpf_map_info info = {};
> + __u32 len = sizeof(info);
> + __u32 id = 0;
>
> obj = bpf_object__open(MAPINMAP_PROG);
>
> @@ -1229,10 +1233,62 @@ static void test_map_in_map(void)
>
> close(fd);
> bpf_object__close(obj);
> +
> +
> + /* Test that failing bpf_object__create_map() destroys the inner map */
> +
> + obj = bpf_object__open(MAPINMAP_INVALID_PROG);
you didn't check bpf_object__open() succeeded here...
> +
> + map = bpf_object__find_map_by_name(obj, "mim");
... and crash will happen here on error
> + if (!map) {
> + printf("Failed to load array of maps from test prog\n");
> + goto out_map_in_map;
> + }
> +
[...]
