On Wed, May 10, 2023 at 3:33 PM JP Kobryn <inwardvessel@xxxxxxxxx> wrote:
>
> This patch adds test coverage for resizing datasec maps. The first two
> subtests resize the bss and custom data sections. In both cases, an
> initial array (of length one) has its element set to one. After resizing
> the rest of the array is filled with ones as well. A BPF program is then
> run to sum the respective arrays and back on the userspace side the sum
> is checked to be equal to the number of elements.
> The third subtest attempts to perform resizing under conditions that
> will result in either the resize failing or the BTF info being dropped.
>
> Signed-off-by: JP Kobryn <inwardvessel@xxxxxxxxx>
> ---
> .../bpf/prog_tests/global_map_resize.c | 236 ++++++++++++++++++
> .../bpf/progs/test_global_map_resize.c | 58 +++++
> 2 files changed, 294 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/prog_tests/global_map_resize.c
> create mode 100644 tools/testing/selftests/bpf/progs/test_global_map_resize.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/global_map_resize.c b/tools/testing/selftests/bpf/prog_tests/global_map_resize.c
> new file mode 100644
> index 000000000000..58961789d0b3
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/global_map_resize.c
> @@ -0,0 +1,236 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
> +#include <errno.h>
> +#include <sys/syscall.h>
> +#include <unistd.h>
> +
> +#include "test_global_map_resize.skel.h"
> +#include "test_progs.h"
> +
> +static void run_prog_bss_array_sum(void)
> +{
> + (void)syscall(__NR_getpid);
> +}
> +
> +static void run_prog_data_array_sum(void)
> +{
> + (void)syscall(__NR_getuid);
> +}
> +
> +static void global_map_resize_bss_subtest(void)
> +{
> + int err;
> + struct test_global_map_resize *skel;
> + struct bpf_map *map;
> + const __u32 desired_sz = sizeof(skel->bss->sum) + (__u32)sysconf(_SC_PAGE_SIZE) * 2;
> + size_t array_len, actual_sz;
> +
> + skel = test_global_map_resize__open();
> + if (!ASSERT_OK_PTR(skel, "test_global_map_resize__open"))
> + goto teardown;
> +
> + /* set some initial value before resizing.
> + * it is expected this non-zero value will be preserved
> + * while resizing.
> + */
> + skel->bss->array[0] = 1;
> +
> + /* resize map value and verify the new size */
> + map = skel->maps.bss;
> + err = bpf_map__set_value_size(map, desired_sz);
> + if (!ASSERT_OK(err, "bpf_map__set_value_size"))
> + goto teardown;
> + if (!ASSERT_EQ(bpf_map__value_size(map), desired_sz, "resize"))
> + goto teardown;
> +
> + /* set the expected number of elements based on the resized array */
> + array_len = (desired_sz - sizeof(skel->bss->sum)) /
> + (__u32)sizeof(skel->bss->array[0]);
(__u32) cast is not necessary, overly pedantic here :) same above for
desired_sz initialization
> + if (!ASSERT_GT(array_len, 1, "array_len"))
> + goto teardown;
> +
> + skel->bss =
> + (struct test_global_map_resize__bss *)bpf_map__initial_value(
> + skel->maps.bss, &actual_sz);
another unnecessary cast making the code ugly, please drop the casting part
> + if (!ASSERT_OK_PTR(skel->bss, "bpf_map__initial_value (ptr)"))
> + goto teardown;
> + if (!ASSERT_EQ(actual_sz, desired_sz, "bpf_map__initial_value (size)"))
> + goto teardown;
> +
> + /* fill the newly resized array with ones,
> + * skipping the first element which was previously set
> + */
> + for (int i = 1; i < array_len; i++)
> + skel->bss->array[i] = 1;
> +
> + /* set global const values before loading */
> + skel->rodata->pid = getpid();
> + skel->rodata->bss_array_len = array_len;
> + skel->rodata->data_array_len = 1;
> +
> + err = test_global_map_resize__load(skel);
> + if (!ASSERT_OK(err, "test_global_map_resize__load"))
> + goto teardown;
> + err = test_global_map_resize__attach(skel);
> + if (!ASSERT_OK(err, "test_global_map_resize__attach"))
> + goto teardown;
> +
> + /* run the bpf program which will sum the contents of the array.
> + * since the array was filled with ones,verify the sum equals array_len
> + */
> + run_prog_bss_array_sum();
> + if (!ASSERT_EQ(skel->bss->sum, array_len, "sum"))
> + goto teardown;
> +
> +teardown:
> + test_global_map_resize__destroy(skel);
> +}
> +
> +static void global_map_resize_data_subtest(void)
> +{
> + int err;
> + struct test_global_map_resize *skel;
> + struct bpf_map *map;
> + const __u32 desired_sz = (__u32)sysconf(_SC_PAGE_SIZE) * 2;
> + size_t array_len, actual_sz;
> +
> + skel = test_global_map_resize__open();
> + if (!ASSERT_OK_PTR(skel, "test_global_map_resize__open"))
> + goto teardown;
> +
> + /* set some initial value before resizing.
> + * it is expected this non-zero value will be preserved
> + * while resizing.
> + */
> + skel->data_custom->my_array[0] = 1;
> +
> + /* resize map value and verify the new size */
> + map = skel->maps.data_custom;
> + err = bpf_map__set_value_size(map, desired_sz);
> + if (!ASSERT_OK(err, "bpf_map__set_value_size"))
> + goto teardown;
> + if (!ASSERT_EQ(bpf_map__value_size(map), desired_sz, "resize"))
> + goto teardown;
> +
> + /* set the expected number of elements based on the resized array */
> + array_len = (desired_sz - sizeof(skel->bss->sum)) /
> + (__u32)sizeof(skel->data_custom->my_array[0]);
> + if (!ASSERT_GT(array_len, 1, "array_len"))
> + goto teardown;
> +
> + skel->data_custom =
> + (struct test_global_map_resize__data_custom *)bpf_map__initial_value(
> + skel->maps.data_custom, &actual_sz);
all the same points about pedantic and unnecessary casts, please simplify
> + if (!ASSERT_OK_PTR(skel->data_custom, "bpf_map__initial_value (ptr)"))
> + goto teardown;
> + if (!ASSERT_EQ(actual_sz, desired_sz, "bpf_map__initial_value (size)"))
> + goto teardown;
> +
> + /* fill the newly resized array with ones,
> + * skipping the first element which was previously set
> + */
> + for (int i = 1; i < array_len; i++)
> + skel->data_custom->my_array[i] = 1;
> +
> + /* set global const values before loading */
> + skel->rodata->pid = getpid();
> + skel->rodata->bss_array_len = 1;
> + skel->rodata->data_array_len = array_len;
> +
> + err = test_global_map_resize__load(skel);
> + if (!ASSERT_OK(err, "test_global_map_resize__load"))
> + goto teardown;
> + err = test_global_map_resize__attach(skel);
> + if (!ASSERT_OK(err, "test_global_map_resize__attach"))
> + goto teardown;
> +
> + /* run the bpf program which will sum the contents of the array.
> + * since the array was filled with ones,verify the sum equals array_len
> + */
> + run_prog_data_array_sum();
> + if (!ASSERT_EQ(skel->bss->sum, array_len, "sum"))
> + goto teardown;
> +
> +teardown:
> + test_global_map_resize__destroy(skel);
> +}
> +
> +static void global_map_resize_invalid_subtest(void)
> +{
> + int err;
> + struct test_global_map_resize *skel;
> + struct bpf_map *map;
> + __u32 element_sz, desired_sz;
> +
> + skel = test_global_map_resize__open();
> + if (!ASSERT_OK_PTR(skel, "test_global_map_resize__open"))
> + return;
> +
> + /* attempt to resize a global datasec map to size
> + * which does NOT align with array
> + */
indentation seems off, please double check
> + map = skel->maps.data_custom;
> + if (!ASSERT_NEQ(bpf_map__btf_value_type_id(map), 0, ".data.custom initial btf"))
> + goto teardown;
> + /* set desired size a fraction of element size beyond an aligned size */
> + element_sz = (__u32)sizeof(skel->data_custom->my_array[0]);
> + desired_sz = element_sz + element_sz / 2;
> + /* confirm desired size does NOT align with array */
> + if (!ASSERT_NEQ(desired_sz % element_sz, 0, "my_array alignment"))
> + goto teardown;
> + err = bpf_map__set_value_size(map, desired_sz);
> + /* confirm resize is OK but BTF info is dropped */
> + if (!ASSERT_OK(err, ".data.custom bpf_map__set_value_size") ||
> + !ASSERT_EQ(bpf_map__btf_key_type_id(map), 0, ".data.custom drop btf key") ||
> + !ASSERT_EQ(bpf_map__btf_value_type_id(map), 0, ".data.custom drop btf val"))
> + goto teardown;
> +
> + /* attempt to resize a global datasec map
> + * whose only var is NOT an array
> + */
> + map = skel->maps.data_non_array;
> + if (!ASSERT_NEQ(bpf_map__btf_value_type_id(map), 0, ".data.non_array initial btf"))
> + goto teardown;
> + /* set desired size to arbitrary value */
> + desired_sz = 1024;
> + err = bpf_map__set_value_size(map, desired_sz);
> + /* confirm resize is OK but BTF info is dropped */
> + if (!ASSERT_OK(err, ".data.non_array bpf_map__set_value_size") ||
> + !ASSERT_EQ(bpf_map__btf_key_type_id(map), 0, ".data.non_array drop btf key") ||
> + !ASSERT_EQ(bpf_map__btf_value_type_id(map), 0, ".data.non_array drop btf val"))
> + goto teardown;
> +
> + /* attempt to resize a global datasec map
> + * whose last var is NOT an array
> + */
> + map = skel->maps.data_array_not_last;
> + if (!ASSERT_NEQ(bpf_map__btf_value_type_id(map), 0, ".data.array_not_last initial btf"))
> + goto teardown;
> + /* set desired size to a multiple of element size */
> + element_sz = (__u32)sizeof(skel->data_array_not_last->my_array_first[0]);
> + desired_sz = element_sz * 8;
> + /* confirm desired size aligns with array */
> + if (!ASSERT_EQ(desired_sz % element_sz, 0, "my_array_first alignment"))
> + goto teardown;
> + err = bpf_map__set_value_size(map, desired_sz);
> + /* confirm resize is OK but BTF info is dropped */
> + if (!ASSERT_OK(err, ".data.array_not_last bpf_map__set_value_size") ||
> + !ASSERT_EQ(bpf_map__btf_key_type_id(map), 0, ".data.array_not_last drop btf key") ||
> + !ASSERT_EQ(bpf_map__btf_value_type_id(map), 0, ".data.array_not_last drop btf val"))
> + goto teardown;
> +
> +teardown:
> + test_global_map_resize__destroy(skel);
> +}
> +
> +void test_global_map_resize(void)
> +{
> + if (test__start_subtest("global_map_resize_bss"))
> + global_map_resize_bss_subtest();
> +
> + if (test__start_subtest("global_map_resize_data"))
> + global_map_resize_data_subtest();
> +
> + if (test__start_subtest("global_map_resize_invalid"))
> + global_map_resize_invalid_subtest();
> +}
> diff --git a/tools/testing/selftests/bpf/progs/test_global_map_resize.c b/tools/testing/selftests/bpf/progs/test_global_map_resize.c
> new file mode 100644
> index 000000000000..2588f2384246
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/test_global_map_resize.c
> @@ -0,0 +1,58 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
> +
> +#include "vmlinux.h"
> +#include <bpf/bpf_helpers.h>
> +
> +char _license[] SEC("license") = "GPL";
> +
> +/* rodata section */
> +const volatile pid_t pid;
> +const volatile size_t bss_array_len;
> +const volatile size_t data_array_len;
> +
> +/* bss section */
> +int sum = 0;
> +int array[1];
> +
> +/* custom data secton */
typo: section
> +int my_array[1] SEC(".data.custom");
> +
> +/* custom data section which should NOT be resizable,
> + * since it contains a single var which is not an array
> + */
> +int my_int SEC(".data.non_array");
> +
> +/* custom data section which should NOT be resizable,
> + * since its last var is not an array
> + */
> +int my_array_first[1] SEC(".data.array_not_last");
> +int my_int_last SEC(".data.array_not_last");
> +
> +SEC("tp/syscalls/sys_enter_getpid")
> +int bss_array_sum(void *ctx)
> +{
> + if (pid != (bpf_get_current_pid_tgid() >> 32))
> + return 0;
> +
> + sum = 0;
> +
> + for (size_t i = 0; i < bss_array_len; ++i)
> + sum += array[i];
> +
> + return 0;
> +}
> +
> +SEC("tp/syscalls/sys_enter_getuid")
> +int data_array_sum(void *ctx)
> +{
> + if (pid != (bpf_get_current_pid_tgid() >> 32))
> + return 0;
> +
> + sum = 0;
> +
> + for (size_t i = 0; i < data_array_len; ++i)
> + sum += my_array[i];
> +
> + return 0;
> +}
> --
> 2.40.0
>
