Merge branch 'Follow ups for kptr series'

Kumar Kartikeya Dwivedi says:

====================

Fix a build time warning, and address comments from Alexei on the merged
version [0].

  [0]: https://lore.kernel.org/bpf/20220424214901.2743946-1-memxor@gmail.com

Changelog:
----------
v1 -> v2
v1: https://lore.kernel.org/bpf/20220510211727.575686-1-memxor@gmail.com

 * Add Fixes tag to patch 1
 * Fix test_progs-noalu32 failure in CI due to different alloc_insn (Alexei)
 * Remove per-CPU struct, use global struct (Alexei)
====================
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

include/linux/bpf.h

@@ -2246,6 +2246,7 @@ extern const struct bpf_func_proto bpf_find_vma_proto;
 extern const struct bpf_func_proto bpf_loop_proto;
 extern const struct bpf_func_proto bpf_strncmp_proto;
 extern const struct bpf_func_proto bpf_copy_from_user_task_proto;
+extern const struct bpf_func_proto bpf_kptr_xchg_proto;
 
 const struct bpf_func_proto *tracing_prog_func_proto(
   enum bpf_func_id func_id, const struct bpf_prog *prog);

net/bpf/test_run.c

@@ -564,31 +564,36 @@ struct prog_test_ref_kfunc {
 	int b;
 	struct prog_test_member memb;
 	struct prog_test_ref_kfunc *next;
+	refcount_t cnt;
 };
 
 static struct prog_test_ref_kfunc prog_test_struct = {
 	.a = 42,
 	.b = 108,
 	.next = &prog_test_struct,
+	.cnt = REFCOUNT_INIT(1),
 };
 
 noinline struct prog_test_ref_kfunc *
 bpf_kfunc_call_test_acquire(unsigned long *scalar_ptr)
 {
-	/* randomly return NULL */
-	if (get_jiffies_64() % 2)
-		return NULL;
+	refcount_inc(&prog_test_struct.cnt);
 	return &prog_test_struct;
 }
 
 noinline struct prog_test_member *
 bpf_kfunc_call_memb_acquire(void)
 {
-	return &prog_test_struct.memb;
+	WARN_ON_ONCE(1);
+	return NULL;
 }
 
 noinline void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p)
 {
+	if (!p)
+		return;
+
+	refcount_dec(&p->cnt);
 }
 
 noinline void bpf_kfunc_call_memb_release(struct prog_test_member *p)
@@ -597,12 +602,18 @@ noinline void bpf_kfunc_call_memb_release(struct prog_test_member *p)
 
 noinline void bpf_kfunc_call_memb1_release(struct prog_test_member1 *p)
 {
+	WARN_ON_ONCE(1);
 }
 
 noinline struct prog_test_ref_kfunc *
-bpf_kfunc_call_test_kptr_get(struct prog_test_ref_kfunc **p, int a, int b)
+bpf_kfunc_call_test_kptr_get(struct prog_test_ref_kfunc **pp, int a, int b)
 {
-	return &prog_test_struct;
+	struct prog_test_ref_kfunc *p = READ_ONCE(*pp);
+
+	if (!p)
+		return NULL;
+	refcount_inc(&p->cnt);
+	return p;
 }
 
 struct prog_test_pass1 {

tools/testing/selftests/bpf/prog_tests/map_kptr.c

 // SPDX-License-Identifier: GPL-2.0
 #include <test_progs.h>
+#include <network_helpers.h>
 
 #include "map_kptr.skel.h"
+#include "map_kptr_fail.skel.h"
 
-void test_map_kptr(void)
+static char log_buf[1024 * 1024];
+
+struct {
+	const char *prog_name;
+	const char *err_msg;
+} map_kptr_fail_tests[] = {
+	{ "size_not_bpf_dw", "kptr access size must be BPF_DW" },
+	{ "non_const_var_off", "kptr access cannot have variable offset" },
+	{ "non_const_var_off_kptr_xchg", "R1 doesn't have constant offset. kptr has to be" },
+	{ "misaligned_access_write", "kptr access misaligned expected=8 off=7" },
+	{ "misaligned_access_read", "kptr access misaligned expected=8 off=1" },
+	{ "reject_var_off_store", "variable untrusted_ptr_ access var_off=(0x0; 0x1e0)" },
+	{ "reject_bad_type_match", "invalid kptr access, R1 type=untrusted_ptr_prog_test_ref_kfunc" },
+	{ "marked_as_untrusted_or_null", "R1 type=untrusted_ptr_or_null_ expected=percpu_ptr_" },
+	{ "correct_btf_id_check_size", "access beyond struct prog_test_ref_kfunc at off 32 size 4" },
+	{ "inherit_untrusted_on_walk", "R1 type=untrusted_ptr_ expected=percpu_ptr_" },
+	{ "reject_kptr_xchg_on_unref", "off=8 kptr isn't referenced kptr" },
+	{ "reject_kptr_get_no_map_val", "arg#0 expected pointer to map value" },
+	{ "reject_kptr_get_no_null_map_val", "arg#0 expected pointer to map value" },
+	{ "reject_kptr_get_no_kptr", "arg#0 no referenced kptr at map value offset=0" },
+	{ "reject_kptr_get_on_unref", "arg#0 no referenced kptr at map value offset=8" },
+	{ "reject_kptr_get_bad_type_match", "kernel function bpf_kfunc_call_test_kptr_get args#0" },
+	{ "mark_ref_as_untrusted_or_null", "R1 type=untrusted_ptr_or_null_ expected=percpu_ptr_" },
+	{ "reject_untrusted_store_to_ref", "store to referenced kptr disallowed" },
+	{ "reject_bad_type_xchg", "invalid kptr access, R2 type=ptr_prog_test_ref_kfunc expected=ptr_prog_test_member" },
+	{ "reject_untrusted_xchg", "R2 type=untrusted_ptr_ expected=ptr_" },
+	{ "reject_member_of_ref_xchg", "invalid kptr access, R2 type=ptr_prog_test_ref_kfunc" },
+	{ "reject_indirect_helper_access", "kptr cannot be accessed indirectly by helper" },
+	{ "reject_indirect_global_func_access", "kptr cannot be accessed indirectly by helper" },
+	{ "kptr_xchg_ref_state", "Unreleased reference id=5 alloc_insn=" },
+	{ "kptr_get_ref_state", "Unreleased reference id=3 alloc_insn=" },
+};
+
+static void test_map_kptr_fail_prog(const char *prog_name, const char *err_msg)
+{
+	LIBBPF_OPTS(bpf_object_open_opts, opts, .kernel_log_buf = log_buf,
+						.kernel_log_size = sizeof(log_buf),
+						.kernel_log_level = 1);
+	struct map_kptr_fail *skel;
+	struct bpf_program *prog;
+	int ret;
+
+	skel = map_kptr_fail__open_opts(&opts);
+	if (!ASSERT_OK_PTR(skel, "map_kptr_fail__open_opts"))
+		return;
+
+	prog = bpf_object__find_program_by_name(skel->obj, prog_name);
+	if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
+		goto end;
+
+	bpf_program__set_autoload(prog, true);
+
+	ret = map_kptr_fail__load(skel);
+	if (!ASSERT_ERR(ret, "map_kptr__load must fail"))
+		goto end;
+
+	if (!ASSERT_OK_PTR(strstr(log_buf, err_msg), "expected error message")) {
+		fprintf(stderr, "Expected: %s\n", err_msg);
+		fprintf(stderr, "Verifier: %s\n", log_buf);
+	}
+
+end:
+	map_kptr_fail__destroy(skel);
+}
+
+static void test_map_kptr_fail(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(map_kptr_fail_tests); i++) {
+		if (!test__start_subtest(map_kptr_fail_tests[i].prog_name))
+			continue;
+		test_map_kptr_fail_prog(map_kptr_fail_tests[i].prog_name,
+					map_kptr_fail_tests[i].err_msg);
+	}
+}
+
+static void test_map_kptr_success(bool test_run)
 {
+	LIBBPF_OPTS(bpf_test_run_opts, opts,
+		.data_in = &pkt_v4,
+		.data_size_in = sizeof(pkt_v4),
+		.repeat = 1,
+	);
 	struct map_kptr *skel;
 	int key = 0, ret;
 	char buf[24];
@@ -13,6 +97,16 @@ void test_map_kptr(void)
 	if (!ASSERT_OK_PTR(skel, "map_kptr__open_and_load"))
 		return;
 
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_map_kptr_ref), &opts);
+	ASSERT_OK(ret, "test_map_kptr_ref refcount");
+	ASSERT_OK(opts.retval, "test_map_kptr_ref retval");
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_map_kptr_ref2), &opts);
+	ASSERT_OK(ret, "test_map_kptr_ref2 refcount");
+	ASSERT_OK(opts.retval, "test_map_kptr_ref2 retval");
+
+	if (test_run)
+		return;
+
 	ret = bpf_map_update_elem(bpf_map__fd(skel->maps.array_map), &key, buf, 0);
 	ASSERT_OK(ret, "array_map update");
 	ret = bpf_map_update_elem(bpf_map__fd(skel->maps.array_map), &key, buf, 0);
@@ -35,3 +129,15 @@ void test_map_kptr(void)
 
 	map_kptr__destroy(skel);
 }
+
+void test_map_kptr(void)
+{
+	if (test__start_subtest("success")) {
+		test_map_kptr_success(false);
+		/* Do test_run twice, so that we see refcount going back to 1
+		 * after we leave it in map from first iteration.
+		 */
+		test_map_kptr_success(true);
+	}
+	test_map_kptr_fail();
+}

tools/testing/selftests/bpf/progs/map_kptr.c

@@ -141,7 +141,7 @@ SEC("tc")
 int test_map_kptr(struct __sk_buff *ctx)
 {
 	struct map_value *v;
-	int i, key = 0;
+	int key = 0;
 
 #define TEST(map)					\
 	v = bpf_map_lookup_elem(&map, &key);		\
@@ -162,7 +162,7 @@ SEC("tc")
 int test_map_in_map_kptr(struct __sk_buff *ctx)
 {
 	struct map_value *v;
-	int i, key = 0;
+	int key = 0;
 	void *map;
 
 #define TEST(map_in_map)                                \
@@ -187,4 +187,106 @@ int test_map_in_map_kptr(struct __sk_buff *ctx)
 	return 0;
 }
 
+SEC("tc")
+int test_map_kptr_ref(struct __sk_buff *ctx)
+{
+	struct prog_test_ref_kfunc *p, *p_st;
+	unsigned long arg = 0;
+	struct map_value *v;
+	int key = 0, ret;
+
+	p = bpf_kfunc_call_test_acquire(&arg);
+	if (!p)
+		return 1;
+
+	p_st = p->next;
+	if (p_st->cnt.refs.counter != 2) {
+		ret = 2;
+		goto end;
+	}
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v) {
+		ret = 3;
+		goto end;
+	}
+
+	p = bpf_kptr_xchg(&v->ref_ptr, p);
+	if (p) {
+		ret = 4;
+		goto end;
+	}
+	if (p_st->cnt.refs.counter != 2)
+		return 5;
+
+	p = bpf_kfunc_call_test_kptr_get(&v->ref_ptr, 0, 0);
+	if (!p)
+		return 6;
+	if (p_st->cnt.refs.counter != 3) {
+		ret = 7;
+		goto end;
+	}
+	bpf_kfunc_call_test_release(p);
+	if (p_st->cnt.refs.counter != 2)
+		return 8;
+
+	p = bpf_kptr_xchg(&v->ref_ptr, NULL);
+	if (!p)
+		return 9;
+	bpf_kfunc_call_test_release(p);
+	if (p_st->cnt.refs.counter != 1)
+		return 10;
+
+	p = bpf_kfunc_call_test_acquire(&arg);
+	if (!p)
+		return 11;
+	p = bpf_kptr_xchg(&v->ref_ptr, p);
+	if (p) {
+		ret = 12;
+		goto end;
+	}
+	if (p_st->cnt.refs.counter != 2)
+		return 13;
+	/* Leave in map */
+
+	return 0;
+end:
+	bpf_kfunc_call_test_release(p);
+	return ret;
+}
+
+SEC("tc")
+int test_map_kptr_ref2(struct __sk_buff *ctx)
+{
+	struct prog_test_ref_kfunc *p, *p_st;
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 1;
+
+	p_st = v->ref_ptr;
+	if (!p_st || p_st->cnt.refs.counter != 2)
+		return 2;
+
+	p = bpf_kptr_xchg(&v->ref_ptr, NULL);
+	if (!p)
+		return 3;
+	if (p_st->cnt.refs.counter != 2) {
+		bpf_kfunc_call_test_release(p);
+		return 4;
+	}
+
+	p = bpf_kptr_xchg(&v->ref_ptr, p);
+	if (p) {
+		bpf_kfunc_call_test_release(p);
+		return 5;
+	}
+	if (p_st->cnt.refs.counter != 2)
+		return 6;
+
+	return 0;
+}
+
 char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/progs/map_kptr_fail.c

+// SPDX-License-Identifier: GPL-2.0
+#include <vmlinux.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+
+struct map_value {
+	char buf[8];
+	struct prog_test_ref_kfunc __kptr *unref_ptr;
+	struct prog_test_ref_kfunc __kptr_ref *ref_ptr;
+	struct prog_test_member __kptr_ref *ref_memb_ptr;
+};
+
+struct array_map {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, int);
+	__type(value, struct map_value);
+	__uint(max_entries, 1);
+} array_map SEC(".maps");
+
+extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
+extern struct prog_test_ref_kfunc *
+bpf_kfunc_call_test_kptr_get(struct prog_test_ref_kfunc **p, int a, int b) __ksym;
+
+SEC("?tc")
+int size_not_bpf_dw(struct __sk_buff *ctx)
+{
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	*(u32 *)&v->unref_ptr = 0;
+	return 0;
+}
+
+SEC("?tc")
+int non_const_var_off(struct __sk_buff *ctx)
+{
+	struct map_value *v;
+	int key = 0, id;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	id = ctx->protocol;
+	if (id < 4 || id > 12)
+		return 0;
+	*(u64 *)((void *)v + id) = 0;
+
+	return 0;
+}
+
+SEC("?tc")
+int non_const_var_off_kptr_xchg(struct __sk_buff *ctx)
+{
+	struct map_value *v;
+	int key = 0, id;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	id = ctx->protocol;
+	if (id < 4 || id > 12)
+		return 0;
+	bpf_kptr_xchg((void *)v + id, NULL);
+
+	return 0;
+}
+
+SEC("?tc")
+int misaligned_access_write(struct __sk_buff *ctx)
+{
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	*(void **)((void *)v + 7) = NULL;
+
+	return 0;
+}
+
+SEC("?tc")
+int misaligned_access_read(struct __sk_buff *ctx)
+{
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	return *(u64 *)((void *)v + 1);
+}
+
+SEC("?tc")
+int reject_var_off_store(struct __sk_buff *ctx)
+{
+	struct prog_test_ref_kfunc *unref_ptr;
+	struct map_value *v;
+	int key = 0, id;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	unref_ptr = v->unref_ptr;
+	if (!unref_ptr)
+		return 0;
+	id = ctx->protocol;
+	if (id < 4 || id > 12)
+		return 0;
+	unref_ptr += id;
+	v->unref_ptr = unref_ptr;
+
+	return 0;
+}
+
+SEC("?tc")
+int reject_bad_type_match(struct __sk_buff *ctx)
+{
+	struct prog_test_ref_kfunc *unref_ptr;
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	unref_ptr = v->unref_ptr;
+	if (!unref_ptr)
+		return 0;
+	unref_ptr = (void *)unref_ptr + 4;
+	v->unref_ptr = unref_ptr;
+
+	return 0;
+}
+
+SEC("?tc")
+int marked_as_untrusted_or_null(struct __sk_buff *ctx)
+{
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	bpf_this_cpu_ptr(v->unref_ptr);
+	return 0;
+}
+
+SEC("?tc")
+int correct_btf_id_check_size(struct __sk_buff *ctx)
+{
+	struct prog_test_ref_kfunc *p;
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	p = v->unref_ptr;
+	if (!p)
+		return 0;
+	return *(int *)((void *)p + bpf_core_type_size(struct prog_test_ref_kfunc));
+}
+
+SEC("?tc")
+int inherit_untrusted_on_walk(struct __sk_buff *ctx)
+{
+	struct prog_test_ref_kfunc *unref_ptr;
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	unref_ptr = v->unref_ptr;
+	if (!unref_ptr)
+		return 0;
+	unref_ptr = unref_ptr->next;
+	bpf_this_cpu_ptr(unref_ptr);
+	return 0;
+}
+
+SEC("?tc")
+int reject_kptr_xchg_on_unref(struct __sk_buff *ctx)
+{
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	bpf_kptr_xchg(&v->unref_ptr, NULL);
+	return 0;
+}
+
+SEC("?tc")
+int reject_kptr_get_no_map_val(struct __sk_buff *ctx)
+{
+	bpf_kfunc_call_test_kptr_get((void *)&ctx, 0, 0);
+	return 0;
+}
+
+SEC("?tc")
+int reject_kptr_get_no_null_map_val(struct __sk_buff *ctx)
+{
+	bpf_kfunc_call_test_kptr_get(bpf_map_lookup_elem(&array_map, &(int){0}), 0, 0);
+	return 0;
+}
+
+SEC("?tc")
+int reject_kptr_get_no_kptr(struct __sk_buff *ctx)
+{
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	bpf_kfunc_call_test_kptr_get((void *)v, 0, 0);
+	return 0;
+}
+
+SEC("?tc")
+int reject_kptr_get_on_unref(struct __sk_buff *ctx)
+{
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	bpf_kfunc_call_test_kptr_get(&v->unref_ptr, 0, 0);
+	return 0;
+}
+
+SEC("?tc")
+int reject_kptr_get_bad_type_match(struct __sk_buff *ctx)
+{
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	bpf_kfunc_call_test_kptr_get((void *)&v->ref_memb_ptr, 0, 0);
+	return 0;
+}
+
+SEC("?tc")
+int mark_ref_as_untrusted_or_null(struct __sk_buff *ctx)
+{
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	bpf_this_cpu_ptr(v->ref_ptr);
+	return 0;
+}
+
+SEC("?tc")
+int reject_untrusted_store_to_ref(struct __sk_buff *ctx)
+{
+	struct prog_test_ref_kfunc *p;
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	p = v->ref_ptr;
+	if (!p)
+		return 0;
+	/* Checkmate, clang */
+	*(struct prog_test_ref_kfunc * volatile *)&v->ref_ptr = p;
+	return 0;
+}
+
+SEC("?tc")
+int reject_untrusted_xchg(struct __sk_buff *ctx)
+{
+	struct prog_test_ref_kfunc *p;
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	p = v->ref_ptr;
+	if (!p)
+		return 0;
+	bpf_kptr_xchg(&v->ref_ptr, p);
+	return 0;
+}
+
+SEC("?tc")
+int reject_bad_type_xchg(struct __sk_buff *ctx)
+{
+	struct prog_test_ref_kfunc *ref_ptr;
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	ref_ptr = bpf_kfunc_call_test_acquire(&(unsigned long){0});
+	if (!ref_ptr)
+		return 0;
+	bpf_kptr_xchg(&v->ref_memb_ptr, ref_ptr);
+	return 0;
+}
+
+SEC("?tc")
+int reject_member_of_ref_xchg(struct __sk_buff *ctx)
+{
+	struct prog_test_ref_kfunc *ref_ptr;
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	ref_ptr = bpf_kfunc_call_test_acquire(&(unsigned long){0});
+	if (!ref_ptr)
+		return 0;
+	bpf_kptr_xchg(&v->ref_memb_ptr, &ref_ptr->memb);
+	return 0;
+}
+
+SEC("?syscall")
+int reject_indirect_helper_access(struct __sk_buff *ctx)
+{
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	bpf_get_current_comm(v, sizeof(v->buf) + 1);
+	return 0;
+}
+
+__noinline
+int write_func(int *p)
+{
+	return p ? *p = 42 : 0;
+}
+
+SEC("?tc")
+int reject_indirect_global_func_access(struct __sk_buff *ctx)
+{
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	return write_func((void *)v + 5);
+}
+
+SEC("?tc")
+int kptr_xchg_ref_state(struct __sk_buff *ctx)
+{
+	struct prog_test_ref_kfunc *p;
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	p = bpf_kfunc_call_test_acquire(&(unsigned long){0});
+	if (!p)
+		return 0;
+	bpf_kptr_xchg(&v->ref_ptr, p);
+	return 0;
+}
+
+SEC("?tc")
+int kptr_get_ref_state(struct __sk_buff *ctx)
+{
+	struct map_value *v;
+	int key = 0;
+
+	v = bpf_map_lookup_elem(&array_map, &key);
+	if (!v)
+		return 0;
+
+	bpf_kfunc_call_test_kptr_get(&v->ref_ptr, 0, 0);
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/verifier/map_kptr.c

@@ -212,13 +212,13 @@
 	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0),
 	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
 	BPF_EXIT_INSN(),
-	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 24),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 32),
 	BPF_EXIT_INSN(),
 	},
 	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
 	.fixup_map_kptr = { 1 },
 	.result = REJECT,
-	.errstr = "access beyond struct prog_test_ref_kfunc at off 24 size 8",
+	.errstr = "access beyond struct prog_test_ref_kfunc at off 32 size 8",
 },
 {
 	"map_kptr: unref: inherit PTR_UNTRUSTED on struct walk",