add simple kfuncs to create/destroy a context type to bpf_testmod,
register them and add a kfunc_call test to use them. This provides
test coverage for registration of dtor kfuncs from modules.
By transferring the context pointer to a map value as a __kptr
we also trigger the map-based dtor cleanup logic, improving test
coverage.
Suggested-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
.../selftests/bpf/bpf_testmod/bpf_testmod.c | 46 +++++++++++++++++++
.../bpf/bpf_testmod/bpf_testmod_kfunc.h | 9 ++++
.../selftests/bpf/prog_tests/kfunc_call.c | 1 +
.../selftests/bpf/progs/kfunc_call_test.c | 37 +++++++++++++++
4 files changed, 93 insertions(+)
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index 49f9a311e49b..fa7f803ea9b5 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -159,6 +159,37 @@ __bpf_kfunc void bpf_kfunc_dynptr_test(struct bpf_dynptr *ptr,
{
}
+__bpf_kfunc struct bpf_testmod_ctx *
+bpf_testmod_ctx_create(int *err)
+{
+ struct bpf_testmod_ctx *ctx;
+
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL | GFP_ATOMIC);
+ if (!ctx) {
+ *err = -ENOMEM;
+ return NULL;
+ }
+ refcount_set(&ctx->usage, 1);
+
+ return ctx;
+}
+
+static void testmod_free_cb(struct rcu_head *head)
+{
+ struct bpf_testmod_ctx *ctx;
+
+ ctx = container_of(head, struct bpf_testmod_ctx, rcu);
+ kfree(ctx);
+}
+
+__bpf_kfunc void bpf_testmod_ctx_release(struct bpf_testmod_ctx *ctx)
+{
+ if (!ctx)
+ return;
+ if (refcount_dec_and_test(&ctx->usage))
+ call_rcu(&ctx->rcu, testmod_free_cb);
+}
+
struct bpf_testmod_btf_type_tag_1 {
int a;
};
@@ -369,8 +400,14 @@ BTF_ID_FLAGS(func, bpf_iter_testmod_seq_next, KF_ITER_NEXT | KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_iter_testmod_seq_destroy, KF_ITER_DESTROY)
BTF_ID_FLAGS(func, bpf_kfunc_common_test)
BTF_ID_FLAGS(func, bpf_kfunc_dynptr_test)
+BTF_ID_FLAGS(func, bpf_testmod_ctx_create, KF_ACQUIRE | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_testmod_ctx_release, KF_RELEASE)
BTF_KFUNCS_END(bpf_testmod_common_kfunc_ids)
+BTF_ID_LIST(bpf_testmod_dtor_ids)
+BTF_ID(struct, bpf_testmod_ctx)
+BTF_ID(func, bpf_testmod_ctx_release)
+
static const struct btf_kfunc_id_set bpf_testmod_common_kfunc_set = {
.owner = THIS_MODULE,
.set = &bpf_testmod_common_kfunc_ids,
@@ -904,6 +941,12 @@ extern int bpf_fentry_test1(int a);
static int bpf_testmod_init(void)
{
+ const struct btf_id_dtor_kfunc bpf_testmod_dtors[] = {
+ {
+ .btf_id = bpf_testmod_dtor_ids[0],
+ .kfunc_btf_id = bpf_testmod_dtor_ids[1]
+ },
+ };
int ret;
ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, &bpf_testmod_common_kfunc_set);
@@ -912,6 +955,9 @@ static int bpf_testmod_init(void)
ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &bpf_testmod_kfunc_set);
ret = ret ?: register_bpf_struct_ops(&bpf_bpf_testmod_ops, bpf_testmod_ops);
ret = ret ?: register_bpf_struct_ops(&bpf_testmod_ops2, bpf_testmod_ops2);
+ ret = ret ?: register_btf_id_dtor_kfuncs(bpf_testmod_dtors,
+ ARRAY_SIZE(bpf_testmod_dtors),
+ THIS_MODULE);
if (ret < 0)
return ret;
if (bpf_fentry_test1(0) < 0)
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
index f9809517e7fa..e587a79f2239 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
@@ -80,6 +80,11 @@ struct sendmsg_args {
int msglen;
};
+struct bpf_testmod_ctx {
+ struct callback_head rcu;
+ refcount_t usage;
+};
+
struct prog_test_ref_kfunc *
bpf_kfunc_call_test_acquire(unsigned long *scalar_ptr) __ksym;
void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
@@ -135,4 +140,8 @@ int bpf_kfunc_call_kernel_getsockname(struct addr_args *args) __ksym;
int bpf_kfunc_call_kernel_getpeername(struct addr_args *args) __ksym;
void bpf_kfunc_dynptr_test(struct bpf_dynptr *ptr, struct bpf_dynptr *ptr__nullable) __ksym;
+
+struct bpf_testmod_ctx *bpf_testmod_ctx_create(int *err) __ksym;
+void bpf_testmod_ctx_release(struct bpf_testmod_ctx *ctx) __ksym;
+
#endif /* _BPF_TESTMOD_KFUNC_H */
diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
index 2eb71559713c..5b743212292f 100644
--- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
+++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
@@ -78,6 +78,7 @@ static struct kfunc_test_params kfunc_tests[] = {
SYSCALL_TEST(kfunc_syscall_test, 0),
SYSCALL_NULL_CTX_TEST(kfunc_syscall_test_null, 0),
TC_TEST(kfunc_call_test_static_unused_arg, 0),
+ TC_TEST(kfunc_call_ctx, 0),
};
struct syscall_test_args {
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test.c b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
index cf68d1e48a0f..f502f755f567 100644
--- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
@@ -177,4 +177,41 @@ int kfunc_call_test_static_unused_arg(struct __sk_buff *skb)
return actual != expected ? -1 : 0;
}
+struct ctx_val {
+ struct bpf_testmod_ctx __kptr *ctx;
+};
+
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __uint(max_entries, 1);
+ __type(key, int);
+ __type(value, struct ctx_val);
+} ctx_map SEC(".maps");
+
+SEC("tc")
+int kfunc_call_ctx(struct __sk_buff *skb)
+{
+ struct bpf_testmod_ctx *ctx;
+ int err = 0;
+
+ ctx = bpf_testmod_ctx_create(&err);
+ if (!ctx && !err)
+ err = -1;
+ if (ctx) {
+ int key = 0;
+ struct ctx_val *ctx_val = bpf_map_lookup_elem(&ctx_map, &key);
+
+ /* Transfer ctx to map to be freed via implicit dtor call
+ * on cleanup.
+ */
+ if (ctx_val)
+ ctx = bpf_kptr_xchg(&ctx_val->ctx, ctx);
+ if (ctx) {
+ bpf_testmod_ctx_release(ctx);
+ err = -1;
+ }
+ }
+ return err;
+}
+
char _license[] SEC("license") = "GPL";
--
2.31.1
