Add a new selftest, local_kptr_stash, which uses bpf_kptr_xchg to stash
a bpf_obj_new-allocated object in a map.
Signed-off-by: Dave Marchevsky <davemarchevsky@xxxxxx>
---
.../bpf/prog_tests/local_kptr_stash.c | 33 +++++++
.../selftests/bpf/progs/local_kptr_stash.c | 85 +++++++++++++++++++
2 files changed, 118 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/local_kptr_stash.c
create mode 100644 tools/testing/selftests/bpf/progs/local_kptr_stash.c
diff --git a/tools/testing/selftests/bpf/prog_tests/local_kptr_stash.c b/tools/testing/selftests/bpf/prog_tests/local_kptr_stash.c
new file mode 100644
index 000000000000..98353e602741
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/local_kptr_stash.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+
+#include <test_progs.h>
+#include <network_helpers.h>
+
+#include "local_kptr_stash.skel.h"
+static void test_local_kptr_stash_simple(void)
+{
+ LIBBPF_OPTS(bpf_test_run_opts, opts,
+ .data_in = &pkt_v4,
+ .data_size_in = sizeof(pkt_v4),
+ .repeat = 1,
+ );
+ struct local_kptr_stash *skel;
+ int ret;
+
+ skel = local_kptr_stash__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "local_kptr_stash__open_and_load"))
+ return;
+
+ ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.stash_rb_node), &opts);
+ ASSERT_OK(ret, "local_kptr_stash_add_nodes run");
+ ASSERT_OK(opts.retval, "local_kptr_stash_add_nodes retval");
+
+ local_kptr_stash__destroy(skel);
+}
+
+void test_local_kptr_stash_success(void)
+{
+ if (test__start_subtest("rbtree_add_nodes"))
+ test_local_kptr_stash_simple();
+}
diff --git a/tools/testing/selftests/bpf/progs/local_kptr_stash.c b/tools/testing/selftests/bpf/progs/local_kptr_stash.c
new file mode 100644
index 000000000000..df7b419f3dc3
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/local_kptr_stash.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+
+#include <vmlinux.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+#include "bpf_experimental.h"
+
+struct node_data {
+ long key;
+ long data;
+ struct bpf_rb_node node;
+};
+
+struct map_value {
+ struct prog_test_ref_kfunc *not_kptr;
+ struct prog_test_ref_kfunc __kptr *val;
+ struct node_data __kptr *node;
+};
+
+/* This is necessary so that LLVM generates BTF for node_data struct
+ * If it's not included, a fwd reference for node_data will be generated but
+ * no struct. Example BTF of "node" field in map_value when not included:
+ *
+ * [10] PTR '(anon)' type_id=35
+ * [34] FWD 'node_data' fwd_kind=struct
+ * [35] TYPE_TAG 'kptr_ref' type_id=34
+ *
+ * (with no node_data struct defined)
+ * Had to do the same w/ bpf_kfunc_call_test_release below
+ */
+struct node_data *just_here_because_btf_bug;
+
+extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
+
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __type(key, int);
+ __type(value, struct map_value);
+ __uint(max_entries, 1);
+} some_nodes SEC(".maps");
+
+SEC("tc")
+long stash_rb_node(void *ctx)
+{
+ struct map_value *mapval;
+ struct node_data *res;
+ int key = 0;
+
+ res = bpf_obj_new(typeof(*res));
+ if (!res)
+ return 1;
+ res->key = 42;
+
+ mapval = bpf_map_lookup_elem(&some_nodes, &key);
+ if (!mapval) {
+ bpf_obj_drop(res);
+ return 1;
+ }
+
+ res = bpf_kptr_xchg(&mapval->node, res);
+ if (res)
+ bpf_obj_drop(res);
+ return 0;
+}
+
+SEC("tc")
+long stash_test_ref_kfunc(void *ctx)
+{
+ struct prog_test_ref_kfunc *res;
+ struct map_value *mapval;
+ int key = 0;
+
+ mapval = bpf_map_lookup_elem(&some_nodes, &key);
+ if (!mapval)
+ return 1;
+
+ res = bpf_kptr_xchg(&mapval->val, NULL);
+ if (res)
+ bpf_kfunc_call_test_release(res);
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.34.1
