[PATCH bpf-next v4 4/4] bpf/selftests: Verify struct_ops prog sleepable behavior

David Vernet
2023-01-25T16:48:03Z

In a set of prior changes, we added the ability for struct_ops programs
to be sleepable. This patch enhances the dummy_st_ops selftest suite to
validate this behavior by adding a new sleepable struct_ops entry to
dummy_st_ops.

Signed-off-by: David Vernet <void@manifault.com>
---
include/linux/bpf.h | 1 +
net/bpf/bpf_dummy_struct_ops.c | 18 +++++++
.../selftests/bpf/prog_tests/dummy_st_ops.c | 52 ++++++++++++++-----
.../selftests/bpf/progs/dummy_st_ops_fail.c | 27 ++++++++++
...{dummy_st_ops.c => dummy_st_ops_success.c} | 19 +++----
5 files changed, 93 insertions(+), 24 deletions(-)
create mode 100644 tools/testing/selftests/bpf/progs/dummy_st_ops_fail.c
rename tools/testing/selftests/bpf/progs/{dummy_st_ops.c => dummy_st_ops_success.c} (72%)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 0d868ef1b973..14a0264fac57 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1474,6 +1474,7 @@ struct bpf_dummy_ops {
int (*test_1)(struct bpf_dummy_ops_state *cb);
int (*test_2)(struct bpf_dummy_ops_state *cb, int a1, unsigned short a2,
char a3, unsigned long a4);
+ int (*test_sleepable)(struct bpf_dummy_ops_state *cb);
};

int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr,
diff --git a/net/bpf/bpf_dummy_struct_ops.c b/net/bpf/bpf_dummy_struct_ops.c
index 1ac4467928a9..ff4f89a2b02a 100644
--- a/net/bpf/bpf_dummy_struct_ops.c
+++ b/net/bpf/bpf_dummy_struct_ops.c
@@ -154,6 +154,23 @@ static bool bpf_dummy_ops_is_valid_access(int off, int size,
return bpf_tracing_btf_ctx_access(off, size, type, prog, info);
}

+static int bpf_dummy_ops_check_member(const struct btf_type *t,
+ const struct btf_member *member,
+ const struct bpf_prog *prog)
+{
+ u32 moff = __btf_member_bit_offset(t, member) / 8;
+
+ switch (moff) {
+ case offsetof(struct bpf_dummy_ops, test_sleepable):
+ break;
+ default:
+ if (prog->aux->sleepable)
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static int bpf_dummy_ops_btf_struct_access(struct bpf_verifier_log *log,
const struct bpf_reg_state *reg,
int off, int size, enum bpf_access_type atype,
@@ -208,6 +225,7 @@ static void bpf_dummy_unreg(void *kdata)
struct bpf_struct_ops bpf_bpf_dummy_ops = {
.verifier_ops = &bpf_dummy_verifier_ops,
.init = bpf_dummy_init,
+ .check_member = bpf_dummy_ops_check_member,
.init_member = bpf_dummy_init_member,
.reg = bpf_dummy_reg,
.unreg = bpf_dummy_unreg,
diff --git a/tools/testing/selftests/bpf/prog_tests/dummy_st_ops.c b/tools/testing/selftests/bpf/prog_tests/dummy_st_ops.c
index c11832657d2b..f43fcb13d2c4 100644
--- a/tools/testing/selftests/bpf/prog_tests/dummy_st_ops.c
+++ b/tools/testing/selftests/bpf/prog_tests/dummy_st_ops.c
@@ -1,7 +1,8 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2021. Huawei Technologies Co., Ltd */
#include <test_progs.h>
-#include "dummy_st_ops.skel.h"
+#include "dummy_st_ops_success.skel.h"
+#include "dummy_st_ops_fail.skel.h"
#include "trace_dummy_st_ops.skel.h"

/* Need to keep consistent with definition in include/linux/bpf.h */
@@ -11,17 +12,17 @@ struct bpf_dummy_ops_state {

static void test_dummy_st_ops_attach(void)
{
- struct dummy_st_ops *skel;
+ struct dummy_st_ops_success *skel;
struct bpf_link *link;

- skel = dummy_st_ops__open_and_load();
+ skel = dummy_st_ops_success__open_and_load();
if (!ASSERT_OK_PTR(skel, "dummy_st_ops_load"))
return;

link = bpf_map__attach_struct_ops(skel->maps.dummy_1);
ASSERT_EQ(libbpf_get_error(link), -EOPNOTSUPP, "dummy_st_ops_attach");

- dummy_st_ops__destroy(skel);
+ dummy_st_ops_success__destroy(skel);
}

static void test_dummy_init_ret_value(void)
@@ -31,10 +32,10 @@ static void test_dummy_init_ret_value(void)
.ctx_in = args,
.ctx_size_in = sizeof(args),
);
- struct dummy_st_ops *skel;
+ struct dummy_st_ops_success *skel;
int fd, err;

- skel = dummy_st_ops__open_and_load();
+ skel = dummy_st_ops_success__open_and_load();
if (!ASSERT_OK_PTR(skel, "dummy_st_ops_load"))
return;

@@ -43,7 +44,7 @@ static void test_dummy_init_ret_value(void)
ASSERT_OK(err, "test_run");
ASSERT_EQ(attr.retval, 0xf2f3f4f5, "test_ret");

- dummy_st_ops__destroy(skel);
+ dummy_st_ops_success__destroy(skel);
}

static void test_dummy_init_ptr_arg(void)
@@ -58,10 +59,10 @@ static void test_dummy_init_ptr_arg(void)
.ctx_size_in = sizeof(args),
);
struct trace_dummy_st_ops *trace_skel;
- struct dummy_st_ops *skel;
+ struct dummy_st_ops_success *skel;
int fd, err;

- skel = dummy_st_ops__open_and_load();
+ skel = dummy_st_ops_success__open_and_load();
if (!ASSERT_OK_PTR(skel, "dummy_st_ops_load"))
return;

@@ -91,7 +92,7 @@ static void test_dummy_init_ptr_arg(void)
ASSERT_EQ(trace_skel->bss->val, exp_retval, "fentry_val");

done:
- dummy_st_ops__destroy(skel);
+ dummy_st_ops_success__destroy(skel);
trace_dummy_st_ops__destroy(trace_skel);
}

@@ -102,12 +103,12 @@ static void test_dummy_multiple_args(void)
.ctx_in = args,
.ctx_size_in = sizeof(args),
);
- struct dummy_st_ops *skel;
+ struct dummy_st_ops_success *skel;
int fd, err;
size_t i;
char name[8];

- skel = dummy_st_ops__open_and_load();
+ skel = dummy_st_ops_success__open_and_load();
if (!ASSERT_OK_PTR(skel, "dummy_st_ops_load"))
return;

@@ -119,7 +120,28 @@ static void test_dummy_multiple_args(void)
ASSERT_EQ(skel->bss->test_2_args[i], args[i], name);
}

- dummy_st_ops__destroy(skel);
+ dummy_st_ops_success__destroy(skel);
+}
+
+static void test_dummy_sleepable(void)
+{
+ __u64 args[1] = {0};
+ LIBBPF_OPTS(bpf_test_run_opts, attr,
+ .ctx_in = args,
+ .ctx_size_in = sizeof(args),
+ );
+ struct dummy_st_ops_success *skel;
+ int fd, err;
+
+ skel = dummy_st_ops_success__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "dummy_st_ops_load"))
+ return;
+
+ fd = bpf_program__fd(skel->progs.test_sleepable);
+ err = bpf_prog_test_run_opts(fd, &attr);
+ ASSERT_OK(err, "test_run");
+
+ dummy_st_ops_success__destroy(skel);
}

void test_dummy_st_ops(void)
@@ -132,4 +154,8 @@ void test_dummy_st_ops(void)
test_dummy_init_ptr_arg();
if (test__start_subtest("dummy_multiple_args"))
test_dummy_multiple_args();
+ if (test__start_subtest("dummy_sleepable"))
+ test_dummy_sleepable();
+
+ RUN_TESTS(dummy_st_ops_fail);
}
diff --git a/tools/testing/selftests/bpf/progs/dummy_st_ops_fail.c b/tools/testing/selftests/bpf/progs/dummy_st_ops_fail.c
new file mode 100644
index 000000000000..0bf969a0b5ed
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/dummy_st_ops_fail.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+#include "bpf_misc.h"
+
+char _license[] SEC("license") = "GPL";
+
+SEC("struct_ops.s/test_2")
+__failure __msg("attach to unsupported member test_2 of struct bpf_dummy_ops")
+int BPF_PROG(test_unsupported_field_sleepable,
+ struct bpf_dummy_ops_state *state, int a1, unsigned short a2,
+ char a3, unsigned long a4)
+{
+ /* Tries to mark an unsleepable field in struct bpf_dummy_ops as sleepable. */
+ return 0;
+}
+
+SEC(".struct_ops")
+struct bpf_dummy_ops dummy_1 = {
+ .test_1 = NULL,
+ .test_2 = (void *)test_unsupported_field_sleepable,
+ .test_sleepable = (void *)NULL,
+};
diff --git a/tools/testing/selftests/bpf/progs/dummy_st_ops.c b/tools/testing/selftests/bpf/progs/dummy_st_ops_success.c
similarity index 72%
rename from tools/testing/selftests/bpf/progs/dummy_st_ops.c
rename to tools/testing/selftests/bpf/progs/dummy_st_ops_success.c
index ead87edb75e2..1efa746c25dc 100644
--- a/tools/testing/selftests/bpf/progs/dummy_st_ops.c
+++ b/tools/testing/selftests/bpf/progs/dummy_st_ops_success.c
@@ -1,19 +1,9 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2021. Huawei Technologies Co., Ltd */
-#include <linux/bpf.h>
+#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>

-struct bpf_dummy_ops_state {
- int val;
-} __attribute__((preserve_access_index));
-
-struct bpf_dummy_ops {
- int (*test_1)(struct bpf_dummy_ops_state *state);
- int (*test_2)(struct bpf_dummy_ops_state *state, int a1, unsigned short a2,
- char a3, unsigned long a4);
-};
-
char _license[] SEC("license") = "GPL";

SEC("struct_ops/test_1")
@@ -43,8 +33,15 @@ int BPF_PROG(test_2, struct bpf_dummy_ops_state *state, int a1, unsigned short a
return 0;
}

+SEC("struct_ops.s/test_sleepable")
+int BPF_PROG(test_sleepable, struct bpf_dummy_ops_state *state)
+{
+ return 0;
+}
+
SEC(".struct_ops")
struct bpf_dummy_ops dummy_1 = {
.test_1 = (void *)test_1,
.test_2 = (void *)test_2,
+ .test_sleepable = (void *)test_sleepable,
};
--
2.39.0