Merge branch 'bpf: Move kernel test kfuncs into bpf_testmod'

Jiri Olsa says:

====================
hi,
I noticed several times in discussions that we should move test kfuncs
into kernel module, now perhaps even more pressing with all the kfunc
effort. This patchset moves all the test kfuncs into bpf_testmod.

I added bpf_testmod/bpf_testmod_kfunc.h header that is shared between
bpf_testmod kernel module and BPF programs.

v4 changes:
  - s390 supports long calls [1] now, so it can call now kfuncs from module [Ilya]
  - added acks [David]
  - cleanups for ptr_to_u64 function [David]
  - use relative path for bpf_testmod_kfunc.h include [Andrii]
  - new libbpf fix (patch 1) for gen_loader

v3 changes:
  - added acks [David]
  - added bpf_testmod.ko make dependency for bpf test progs [David]
  - better handling of __ksym and refcount_t in bpf_testmod_kfunc.h [David]
  - removed 'extern' from kfuncs declarations [David]
  - typo in header guard macro [David]
  - use only stdout in un/load_bpf_testmod

v2 changes:
  - add 74bc3a5acc82 into bpf-next/master CI, so the test would pass
    https://github.com/kernel-patches/vmtest/pull/192
  - remove extra externs [Artem]
  - using un/load_bpf_testmod in other tests
  - rebased

thanks,
jirka

[1] 1cf3bfc60f98 bpf: Support 64-bit pointers to kfuncs
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

21 files changed, 521 insertions, 386 deletions

diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 98143b86a9dd..2321bd2f9964 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -561,29 +561,6 @@ __bpf_kfunc int bpf_modify_return_test(int a, int *b)
 	return a + *b;
 }
 
-__bpf_kfunc u64 bpf_kfunc_call_test1(struct sock *sk, u32 a, u64 b, u32 c, u64 d)
-{
-	return a + b + c + d;
-}
-
-__bpf_kfunc int bpf_kfunc_call_test2(struct sock *sk, u32 a, u32 b)
-{
-	return a + b;
-}
-
-__bpf_kfunc struct sock *bpf_kfunc_call_test3(struct sock *sk)
-{
-	return sk;
-}
-
-long noinline bpf_kfunc_call_test4(signed char a, short b, int c, long d)
-{
-	/* Provoke the compiler to assume that the caller has sign-extended a,
-	 * b and c on platforms where this is required (e.g. s390x).
-	 */
-	return (long)a + (long)b + (long)c + d;
-}
-
 int noinline bpf_fentry_shadow_test(int a)
 {
 	return a + 1;
@@ -606,32 +583,6 @@ struct prog_test_ref_kfunc {
 	refcount_t cnt;
 };
 
-static struct prog_test_ref_kfunc prog_test_struct = {
-	.a = 42,
-	.b = 108,
-	.next = &prog_test_struct,
-	.cnt = REFCOUNT_INIT(1),
-};
-
-__bpf_kfunc struct prog_test_ref_kfunc *
-bpf_kfunc_call_test_acquire(unsigned long *scalar_ptr)
-{
-	refcount_inc(&prog_test_struct.cnt);
-	return &prog_test_struct;
-}
-
-__bpf_kfunc void bpf_kfunc_call_test_offset(struct prog_test_ref_kfunc *p)
-{
-	WARN_ON_ONCE(1);
-}
-
-__bpf_kfunc struct prog_test_member *
-bpf_kfunc_call_memb_acquire(void)
-{
-	WARN_ON_ONCE(1);
-	return NULL;
-}
-
 __bpf_kfunc void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p)
 {
 	refcount_dec(&p->cnt);
@@ -641,134 +592,6 @@ __bpf_kfunc void bpf_kfunc_call_memb_release(struct prog_test_member *p)
 {
 }
 
-__bpf_kfunc void bpf_kfunc_call_memb1_release(struct prog_test_member1 *p)
-{
-	WARN_ON_ONCE(1);
-}
-
-static int *__bpf_kfunc_call_test_get_mem(struct prog_test_ref_kfunc *p, const int size)
-{
-	if (size > 2 * sizeof(int))
-		return NULL;
-
-	return (int *)p;
-}
-
-__bpf_kfunc int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p,
-						  const int rdwr_buf_size)
-{
-	return __bpf_kfunc_call_test_get_mem(p, rdwr_buf_size);
-}
-
-__bpf_kfunc int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p,
-						    const int rdonly_buf_size)
-{
-	return __bpf_kfunc_call_test_get_mem(p, rdonly_buf_size);
-}
-
-/* the next 2 ones can't be really used for testing expect to ensure
- * that the verifier rejects the call.
- * Acquire functions must return struct pointers, so these ones are
- * failing.
- */
-__bpf_kfunc int *bpf_kfunc_call_test_acq_rdonly_mem(struct prog_test_ref_kfunc *p,
-						    const int rdonly_buf_size)
-{
-	return __bpf_kfunc_call_test_get_mem(p, rdonly_buf_size);
-}
-
-__bpf_kfunc void bpf_kfunc_call_int_mem_release(int *p)
-{
-}
-
-struct prog_test_pass1 {
-	int x0;
-	struct {
-		int x1;
-		struct {
-			int x2;
-			struct {
-				int x3;
-			};
-		};
-	};
-};
-
-struct prog_test_pass2 {
-	int len;
-	short arr1[4];
-	struct {
-		char arr2[4];
-		unsigned long arr3[8];
-	} x;
-};
-
-struct prog_test_fail1 {
-	void *p;
-	int x;
-};
-
-struct prog_test_fail2 {
-	int x8;
-	struct prog_test_pass1 x;
-};
-
-struct prog_test_fail3 {
-	int len;
-	char arr1[2];
-	char arr2[];
-};
-
-__bpf_kfunc void bpf_kfunc_call_test_pass_ctx(struct __sk_buff *skb)
-{
-}
-
-__bpf_kfunc void bpf_kfunc_call_test_pass1(struct prog_test_pass1 *p)
-{
-}
-
-__bpf_kfunc void bpf_kfunc_call_test_pass2(struct prog_test_pass2 *p)
-{
-}
-
-__bpf_kfunc void bpf_kfunc_call_test_fail1(struct prog_test_fail1 *p)
-{
-}
-
-__bpf_kfunc void bpf_kfunc_call_test_fail2(struct prog_test_fail2 *p)
-{
-}
-
-__bpf_kfunc void bpf_kfunc_call_test_fail3(struct prog_test_fail3 *p)
-{
-}
-
-__bpf_kfunc void bpf_kfunc_call_test_mem_len_pass1(void *mem, int mem__sz)
-{
-}
-
-__bpf_kfunc void bpf_kfunc_call_test_mem_len_fail1(void *mem, int len)
-{
-}
-
-__bpf_kfunc void bpf_kfunc_call_test_mem_len_fail2(u64 *mem, int len)
-{
-}
-
-__bpf_kfunc void bpf_kfunc_call_test_ref(struct prog_test_ref_kfunc *p)
-{
-	/* p != NULL, but p->cnt could be 0 */
-}
-
-__bpf_kfunc void bpf_kfunc_call_test_destructive(void)
-{
-}
-
-__bpf_kfunc static u32 bpf_kfunc_call_test_static_unused_arg(u32 arg, u32 unused)
-{
-	return arg;
-}
-
 __diag_pop();
 
 BTF_SET8_START(bpf_test_modify_return_ids)
@@ -782,32 +605,8 @@ static const struct btf_kfunc_id_set bpf_test_modify_return_set = {
 };
 
 BTF_SET8_START(test_sk_check_kfunc_ids)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test2)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test3)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test4)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_acquire, KF_ACQUIRE | KF_RET_NULL)
-BTF_ID_FLAGS(func, bpf_kfunc_call_memb_acquire, KF_ACQUIRE | KF_RET_NULL)
 BTF_ID_FLAGS(func, bpf_kfunc_call_test_release, KF_RELEASE)
 BTF_ID_FLAGS(func, bpf_kfunc_call_memb_release, KF_RELEASE)
-BTF_ID_FLAGS(func, bpf_kfunc_call_memb1_release, KF_RELEASE)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_get_rdwr_mem, KF_RET_NULL)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_get_rdonly_mem, KF_RET_NULL)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_acq_rdonly_mem, KF_ACQUIRE | KF_RET_NULL)
-BTF_ID_FLAGS(func, bpf_kfunc_call_int_mem_release, KF_RELEASE)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_pass_ctx)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_pass1)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_pass2)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_fail1)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_fail2)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_fail3)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_pass1)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail1)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail2)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_ref, KF_TRUSTED_ARGS | KF_RCU)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_destructive, KF_DESTRUCTIVE)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_static_unused_arg)
-BTF_ID_FLAGS(func, bpf_kfunc_call_test_offset)
 BTF_SET8_END(test_sk_check_kfunc_ids)
 
 static void *bpf_test_init(const union bpf_attr *kattr, u32 user_size,
diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c
index 83e8e3bfd8ff..cf3323fd47b8 100644
--- a/tools/lib/bpf/gen_loader.c
+++ b/tools/lib/bpf/gen_loader.c
@@ -703,17 +703,17 @@ static void emit_relo_kfunc_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo
 	/* obtain fd in BPF_REG_9 */
 	emit(gen, BPF_MOV64_REG(BPF_REG_9, BPF_REG_7));
 	emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32));
-	/* jump to fd_array store if fd denotes module BTF */
-	emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 0, 2));
-	/* set the default value for off */
-	emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), 0));
-	/* skip BTF fd store for vmlinux BTF */
-	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 4));
 	/* load fd_array slot pointer */
 	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
 					 0, 0, 0, blob_fd_array_off(gen, btf_fd_idx)));
-	/* store BTF fd in slot */
+	/* store BTF fd in slot, 0 for vmlinux */
 	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_9, 0));
+	/* jump to insn[insn_idx].off store if fd denotes module BTF */
+	emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 0, 2));
+	/* set the default value for off */
+	emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), 0));
+	/* skip BTF fd store for vmlinux BTF */
+	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 1));
 	/* store index into insn[insn_idx].off */
 	emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), btf_fd_idx));
 log:
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index 52785ba671e6..cf216041876c 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -9,6 +9,7 @@
 #include <linux/sysfs.h>
 #include <linux/tracepoint.h>
 #include "bpf_testmod.h"
+#include "bpf_testmod_kfunc.h"
 
 #define CREATE_TRACE_POINTS
 #include "bpf_testmod-events.h"
@@ -289,8 +290,171 @@ static const struct btf_kfunc_id_set bpf_testmod_common_kfunc_set = {
 	.set   = &bpf_testmod_common_kfunc_ids,
 };
 
+__bpf_kfunc u64 bpf_kfunc_call_test1(struct sock *sk, u32 a, u64 b, u32 c, u64 d)
+{
+	return a + b + c + d;
+}
+
+__bpf_kfunc int bpf_kfunc_call_test2(struct sock *sk, u32 a, u32 b)
+{
+	return a + b;
+}
+
+__bpf_kfunc struct sock *bpf_kfunc_call_test3(struct sock *sk)
+{
+	return sk;
+}
+
+__bpf_kfunc long noinline bpf_kfunc_call_test4(signed char a, short b, int c, long d)
+{
+	/* Provoke the compiler to assume that the caller has sign-extended a,
+	 * b and c on platforms where this is required (e.g. s390x).
+	 */
+	return (long)a + (long)b + (long)c + d;
+}
+
+static struct prog_test_ref_kfunc prog_test_struct = {
+	.a = 42,
+	.b = 108,
+	.next = &prog_test_struct,
+	.cnt = REFCOUNT_INIT(1),
+};
+
+__bpf_kfunc struct prog_test_ref_kfunc *
+bpf_kfunc_call_test_acquire(unsigned long *scalar_ptr)
+{
+	refcount_inc(&prog_test_struct.cnt);
+	return &prog_test_struct;
+}
+
+__bpf_kfunc void bpf_kfunc_call_test_offset(struct prog_test_ref_kfunc *p)
+{
+	WARN_ON_ONCE(1);
+}
+
+__bpf_kfunc struct prog_test_member *
+bpf_kfunc_call_memb_acquire(void)
+{
+	WARN_ON_ONCE(1);
+	return NULL;
+}
+
+__bpf_kfunc void bpf_kfunc_call_memb1_release(struct prog_test_member1 *p)
+{
+	WARN_ON_ONCE(1);
+}
+
+static int *__bpf_kfunc_call_test_get_mem(struct prog_test_ref_kfunc *p, const int size)
+{
+	if (size > 2 * sizeof(int))
+		return NULL;
+
+	return (int *)p;
+}
+
+__bpf_kfunc int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p,
+						  const int rdwr_buf_size)
+{
+	return __bpf_kfunc_call_test_get_mem(p, rdwr_buf_size);
+}
+
+__bpf_kfunc int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p,
+						    const int rdonly_buf_size)
+{
+	return __bpf_kfunc_call_test_get_mem(p, rdonly_buf_size);
+}
+
+/* the next 2 ones can't be really used for testing expect to ensure
+ * that the verifier rejects the call.
+ * Acquire functions must return struct pointers, so these ones are
+ * failing.
+ */
+__bpf_kfunc int *bpf_kfunc_call_test_acq_rdonly_mem(struct prog_test_ref_kfunc *p,
+						    const int rdonly_buf_size)
+{
+	return __bpf_kfunc_call_test_get_mem(p, rdonly_buf_size);
+}
+
+__bpf_kfunc void bpf_kfunc_call_int_mem_release(int *p)
+{
+}
+
+__bpf_kfunc void bpf_kfunc_call_test_pass_ctx(struct __sk_buff *skb)
+{
+}
+
+__bpf_kfunc void bpf_kfunc_call_test_pass1(struct prog_test_pass1 *p)
+{
+}
+
+__bpf_kfunc void bpf_kfunc_call_test_pass2(struct prog_test_pass2 *p)
+{
+}
+
+__bpf_kfunc void bpf_kfunc_call_test_fail1(struct prog_test_fail1 *p)
+{
+}
+
+__bpf_kfunc void bpf_kfunc_call_test_fail2(struct prog_test_fail2 *p)
+{
+}
+
+__bpf_kfunc void bpf_kfunc_call_test_fail3(struct prog_test_fail3 *p)
+{
+}
+
+__bpf_kfunc void bpf_kfunc_call_test_mem_len_pass1(void *mem, int mem__sz)
+{
+}
+
+__bpf_kfunc void bpf_kfunc_call_test_mem_len_fail1(void *mem, int len)
+{
+}
+
+__bpf_kfunc void bpf_kfunc_call_test_mem_len_fail2(u64 *mem, int len)
+{
+}
+
+__bpf_kfunc void bpf_kfunc_call_test_ref(struct prog_test_ref_kfunc *p)
+{
+	/* p != NULL, but p->cnt could be 0 */
+}
+
+__bpf_kfunc void bpf_kfunc_call_test_destructive(void)
+{
+}
+
+__bpf_kfunc static u32 bpf_kfunc_call_test_static_unused_arg(u32 arg, u32 unused)
+{
+	return arg;
+}
+
 BTF_SET8_START(bpf_testmod_check_kfunc_ids)
 BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test2)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test3)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test4)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_pass1)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail1)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail2)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_acquire, KF_ACQUIRE | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_kfunc_call_memb_acquire, KF_ACQUIRE | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_kfunc_call_memb1_release, KF_RELEASE)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_get_rdwr_mem, KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_get_rdonly_mem, KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_acq_rdonly_mem, KF_ACQUIRE | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_kfunc_call_int_mem_release, KF_RELEASE)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_pass_ctx)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_pass1)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_pass2)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_fail1)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_fail2)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_fail3)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_ref, KF_TRUSTED_ARGS | KF_RCU)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_destructive, KF_DESTRUCTIVE)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_static_unused_arg)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_offset)
 BTF_SET8_END(bpf_testmod_check_kfunc_ids)
 
 static const struct btf_kfunc_id_set bpf_testmod_kfunc_set = {
@@ -312,6 +476,8 @@ static int bpf_testmod_init(void)
 
 	ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, &bpf_testmod_common_kfunc_set);
 	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_testmod_kfunc_set);
+	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &bpf_testmod_kfunc_set);
+	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &bpf_testmod_kfunc_set);
 	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
new file mode 100644
index 000000000000..9693c626646b
--- /dev/null
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _BPF_TESTMOD_KFUNC_H
+#define _BPF_TESTMOD_KFUNC_H
+
+#ifndef __KERNEL__
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#else
+#define __ksym
+struct prog_test_member1 {
+	int a;
+};
+
+struct prog_test_member {
+	struct prog_test_member1 m;
+	int c;
+};
+
+struct prog_test_ref_kfunc {
+	int a;
+	int b;
+	struct prog_test_member memb;
+	struct prog_test_ref_kfunc *next;
+	refcount_t cnt;
+};
+#endif
+
+struct prog_test_pass1 {
+	int x0;
+	struct {
+		int x1;
+		struct {
+			int x2;
+			struct {
+				int x3;
+			};
+		};
+	};
+};
+
+struct prog_test_pass2 {
+	int len;
+	short arr1[4];
+	struct {
+		char arr2[4];
+		unsigned long arr3[8];
+	} x;
+};
+
+struct prog_test_fail1 {
+	void *p;
+	int x;
+};
+
+struct prog_test_fail2 {
+	int x8;
+	struct prog_test_pass1 x;
+};
+
+struct prog_test_fail3 {
+	int len;
+	char arr1[2];
+	char arr2[];
+};
+
+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;
+void bpf_kfunc_call_test_ref(struct prog_test_ref_kfunc *p) __ksym;
+
+void bpf_kfunc_call_test_mem_len_pass1(void *mem, int len) __ksym;
+int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, const int rdwr_buf_size) __ksym;
+int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym;
+int *bpf_kfunc_call_test_acq_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym;
+void bpf_kfunc_call_int_mem_release(int *p) __ksym;
+
+/* The bpf_kfunc_call_test_static_unused_arg is defined as static,
+ * but bpf program compilation needs to see it as global symbol.
+ */
+#ifndef __KERNEL__
+u32 bpf_kfunc_call_test_static_unused_arg(u32 arg, u32 unused) __ksym;
+#endif
+
+void bpf_testmod_test_mod_kfunc(int i) __ksym;
+
+__u64 bpf_kfunc_call_test1(struct sock *sk, __u32 a, __u64 b,
+				__u32 c, __u64 d) __ksym;
+int bpf_kfunc_call_test2(struct sock *sk, __u32 a, __u32 b) __ksym;
+struct sock *bpf_kfunc_call_test3(struct sock *sk) __ksym;
+long bpf_kfunc_call_test4(signed char a, short b, int c, long d) __ksym;
+
+void bpf_kfunc_call_test_pass_ctx(struct __sk_buff *skb) __ksym;
+void bpf_kfunc_call_test_pass1(struct prog_test_pass1 *p) __ksym;
+void bpf_kfunc_call_test_pass2(struct prog_test_pass2 *p) __ksym;
+void bpf_kfunc_call_test_mem_len_fail2(__u64 *mem, int len) __ksym;
+
+void bpf_kfunc_call_test_destructive(void) __ksym;
+
+#endif /* _BPF_TESTMOD_KFUNC_H */
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_mod_race.c b/tools/testing/selftests/bpf/prog_tests/bpf_mod_race.c
index a4d0cc9d3367..fe2c502e5089 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_mod_race.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_mod_race.c
@@ -11,6 +11,7 @@
 #include "ksym_race.skel.h"
 #include "bpf_mod_race.skel.h"
 #include "kfunc_call_race.skel.h"
+#include "testing_helpers.h"
 
 /* This test crafts a race between btf_try_get_module and do_init_module, and
  * checks whether btf_try_get_module handles the invocation for a well-formed
@@ -44,35 +45,10 @@ enum bpf_test_state {
 
 static _Atomic enum bpf_test_state state = _TS_INVALID;
 
-static int sys_finit_module(int fd, const char *param_values, int flags)
-{
-	return syscall(__NR_finit_module, fd, param_values, flags);
-}
-
-static int sys_delete_module(const char *name, unsigned int flags)
-{
-	return syscall(__NR_delete_module, name, flags);
-}
-
-static int load_module(const char *mod)
-{
-	int ret, fd;
-
-	fd = open("bpf_testmod.ko", O_RDONLY);
-	if (fd < 0)
-		return fd;
-
-	ret = sys_finit_module(fd, "", 0);
-	close(fd);
-	if (ret < 0)
-		return ret;
-	return 0;
-}
-
 static void *load_module_thread(void *p)
 {
 
-	if (!ASSERT_NEQ(load_module("bpf_testmod.ko"), 0, "load_module_thread must fail"))
+	if (!ASSERT_NEQ(load_bpf_testmod(false), 0, "load_module_thread must fail"))
 		atomic_store(&state, TS_MODULE_LOAD);
 	else
 		atomic_store(&state, TS_MODULE_LOAD_FAIL);
@@ -124,7 +100,7 @@ static void test_bpf_mod_race_config(const struct test_config *config)
 	if (!ASSERT_NEQ(fault_addr, MAP_FAILED, "mmap for uffd registration"))
 		return;
 
-	if (!ASSERT_OK(sys_delete_module("bpf_testmod", 0), "unload bpf_testmod"))
+	if (!ASSERT_OK(unload_bpf_testmod(false), "unload bpf_testmod"))
 		goto end_mmap;
 
 	skel = bpf_mod_race__open();
@@ -202,8 +178,8 @@ end_destroy:
 	bpf_mod_race__destroy(skel);
 	ASSERT_OK(kern_sync_rcu(), "kern_sync_rcu");
 end_module:
-	sys_delete_module("bpf_testmod", 0);
-	ASSERT_OK(load_module("bpf_testmod.ko"), "restore bpf_testmod");
+	unload_bpf_testmod(false);
+	ASSERT_OK(load_bpf_testmod(false), "restore bpf_testmod");
 end_mmap:
 	munmap(fault_addr, 4096);
 	atomic_store(&state, _TS_INVALID);
diff --git a/tools/testing/selftests/bpf/prog_tests/module_attach.c b/tools/testing/selftests/bpf/prog_tests/module_attach.c
index 7fc01ff490db..f53d658ed080 100644
--- a/tools/testing/selftests/bpf/prog_tests/module_attach.c
+++ b/tools/testing/selftests/bpf/prog_tests/module_attach.c
@@ -4,6 +4,7 @@
 #include <test_progs.h>
 #include <stdbool.h>
 #include "test_module_attach.skel.h"
+#include "testing_helpers.h"
 
 static int duration;
 
@@ -32,11 +33,6 @@ static int trigger_module_test_writable(int *val)
 	return 0;
 }
 
-static int delete_module(const char *name, int flags)
-{
-	return syscall(__NR_delete_module, name, flags);
-}
-
 void test_module_attach(void)
 {
 	const int READ_SZ = 456;
@@ -93,21 +89,21 @@ void test_module_attach(void)
 	if (!ASSERT_OK_PTR(link, "attach_fentry"))
 		goto cleanup;
 
-	ASSERT_ERR(delete_module("bpf_testmod", 0), "delete_module");
+	ASSERT_ERR(unload_bpf_testmod(false), "unload_bpf_testmod");
 	bpf_link__destroy(link);
 
 	link = bpf_program__attach(skel->progs.handle_fexit);
 	if (!ASSERT_OK_PTR(link, "attach_fexit"))
 		goto cleanup;
 
-	ASSERT_ERR(delete_module("bpf_testmod", 0), "delete_module");
+	ASSERT_ERR(unload_bpf_testmod(false), "unload_bpf_testmod");
 	bpf_link__destroy(link);
 
 	link = bpf_program__attach(skel->progs.kprobe_multi);
 	if (!ASSERT_OK_PTR(link, "attach_kprobe_multi"))
 		goto cleanup;
 
-	ASSERT_ERR(delete_module("bpf_testmod", 0), "delete_module");
+	ASSERT_ERR(unload_bpf_testmod(false), "unload_bpf_testmod");
 	bpf_link__destroy(link);
 
 cleanup:
diff --git a/tools/testing/selftests/bpf/progs/cb_refs.c b/tools/testing/selftests/bpf/progs/cb_refs.c
index 50f95ec61165..76d661b20e87 100644
--- a/tools/testing/selftests/bpf/progs/cb_refs.c
+++ b/tools/testing/selftests/bpf/progs/cb_refs.c
@@ -2,6 +2,7 @@
 #include <vmlinux.h>
 #include <bpf/bpf_tracing.h>
 #include <bpf/bpf_helpers.h>
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 struct map_value {
 	struct prog_test_ref_kfunc __kptr *ptr;
@@ -14,9 +15,6 @@ struct {
 	__uint(max_entries, 16);
 } array_map SEC(".maps");
 
-extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
-extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
-
 static __noinline int cb1(void *map, void *key, void *value, void *ctx)
 {
 	void *p = *(void **)ctx;
diff --git a/tools/testing/selftests/bpf/progs/jit_probe_mem.c b/tools/testing/selftests/bpf/progs/jit_probe_mem.c
index 13f00ca2ed0a..f9789e668297 100644
--- a/tools/testing/selftests/bpf/progs/jit_probe_mem.c
+++ b/tools/testing/selftests/bpf/progs/jit_probe_mem.c
@@ -3,13 +3,11 @@
 #include <vmlinux.h>
 #include <bpf/bpf_tracing.h>
 #include <bpf/bpf_helpers.h>
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 static struct prog_test_ref_kfunc __kptr *v;
 long total_sum = -1;
 
-extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
-extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
-
 SEC("tc")
 int test_jit_probe_mem(struct __sk_buff *ctx)
 {
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_destructive.c b/tools/testing/selftests/bpf/progs/kfunc_call_destructive.c
index 767472bc5a97..7632d9ecb253 100644
--- a/tools/testing/selftests/bpf/progs/kfunc_call_destructive.c
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_destructive.c
@@ -1,8 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
-
-extern void bpf_kfunc_call_test_destructive(void) __ksym;
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 SEC("tc")
 int kfunc_destructive_test(void)
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_fail.c b/tools/testing/selftests/bpf/progs/kfunc_call_fail.c
index b98313d391c6..4b0b7b79cdfb 100644
--- a/tools/testing/selftests/bpf/progs/kfunc_call_fail.c
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_fail.c
@@ -2,14 +2,7 @@
 /* Copyright (c) 2021 Facebook */
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
-
-extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
-extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
-extern void bpf_kfunc_call_test_mem_len_pass1(void *mem, int len) __ksym;
-extern int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, const int rdwr_buf_size) __ksym;
-extern int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym;
-extern int *bpf_kfunc_call_test_acq_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym;
-extern void bpf_kfunc_call_int_mem_release(int *p) __ksym;
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 struct syscall_test_args {
 	__u8 data[16];
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_race.c b/tools/testing/selftests/bpf/progs/kfunc_call_race.c
index 4e8fed75a4e0..d532af07decf 100644
--- a/tools/testing/selftests/bpf/progs/kfunc_call_race.c
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_race.c
@@ -1,8 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
-
-extern void bpf_testmod_test_mod_kfunc(int i) __ksym;
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 SEC("tc")
 int kfunc_call_fail(struct __sk_buff *ctx)
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test.c b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
index 7daa8f5720b9..cf68d1e48a0f 100644
--- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
@@ -2,22 +2,7 @@
 /* Copyright (c) 2021 Facebook */
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
-
-extern long bpf_kfunc_call_test4(signed char a, short b, int c, long d) __ksym;
-extern int bpf_kfunc_call_test2(struct sock *sk, __u32 a, __u32 b) __ksym;
-extern __u64 bpf_kfunc_call_test1(struct sock *sk, __u32 a, __u64 b,
-				  __u32 c, __u64 d) __ksym;
-
-extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
-extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
-extern void bpf_kfunc_call_test_pass_ctx(struct __sk_buff *skb) __ksym;
-extern void bpf_kfunc_call_test_pass1(struct prog_test_pass1 *p) __ksym;
-extern void bpf_kfunc_call_test_pass2(struct prog_test_pass2 *p) __ksym;
-extern void bpf_kfunc_call_test_mem_len_pass1(void *mem, int len) __ksym;
-extern void bpf_kfunc_call_test_mem_len_fail2(__u64 *mem, int len) __ksym;
-extern int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, const int rdwr_buf_size) __ksym;
-extern int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym;
-extern u32 bpf_kfunc_call_test_static_unused_arg(u32 arg, u32 unused) __ksym;
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 SEC("tc")
 int kfunc_call_test4(struct __sk_buff *skb)
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c b/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c
index c1fdecabeabf..2380c75e74ce 100644
--- a/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c
@@ -1,13 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright (c) 2021 Facebook */
-#include <linux/bpf.h>
-#include <bpf/bpf_helpers.h>
-#include "bpf_tcp_helpers.h"
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 extern const int bpf_prog_active __ksym;
-extern __u64 bpf_kfunc_call_test1(struct sock *sk, __u32 a, __u64 b,
-				  __u32 c, __u64 d) __ksym;
-extern struct sock *bpf_kfunc_call_test3(struct sock *sk) __ksym;
 int active_res = -1;
 int sk_state_res = -1;
 
@@ -28,7 +23,7 @@ int __noinline f1(struct __sk_buff *skb)
 	if (active)
 		active_res = *active;
 
-	sk_state_res = bpf_kfunc_call_test3((struct sock *)sk)->sk_state;
+	sk_state_res = bpf_kfunc_call_test3((struct sock *)sk)->__sk_common.skc_state;
 
 	return (__u32)bpf_kfunc_call_test1((struct sock *)sk, 1, 2, 3, 4);
 }
diff --git a/tools/testing/selftests/bpf/progs/local_kptr_stash.c b/tools/testing/selftests/bpf/progs/local_kptr_stash.c
index 0ef286da092b..06838083079c 100644
--- a/tools/testing/selftests/bpf/progs/local_kptr_stash.c
+++ b/tools/testing/selftests/bpf/progs/local_kptr_stash.c
@@ -5,7 +5,8 @@
 #include <bpf/bpf_tracing.h>
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_core_read.h>
-#include "bpf_experimental.h"
+#include "../bpf_experimental.h"
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 struct node_data {
 	long key;
@@ -32,8 +33,6 @@ struct map_value {
  */
 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);
diff --git a/tools/testing/selftests/bpf/progs/map_kptr.c b/tools/testing/selftests/bpf/progs/map_kptr.c
index d7150041e5d1..da30f0d59364 100644
--- a/tools/testing/selftests/bpf/progs/map_kptr.c
+++ b/tools/testing/selftests/bpf/progs/map_kptr.c
@@ -2,6 +2,7 @@
 #include <vmlinux.h>
 #include <bpf/bpf_tracing.h>
 #include <bpf/bpf_helpers.h>
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 struct map_value {
 	struct prog_test_ref_kfunc __kptr_untrusted *unref_ptr;
@@ -114,10 +115,6 @@ DEFINE_MAP_OF_MAP(BPF_MAP_TYPE_HASH_OF_MAPS, hash_map, hash_of_hash_maps);
 DEFINE_MAP_OF_MAP(BPF_MAP_TYPE_HASH_OF_MAPS, hash_malloc_map, hash_of_hash_malloc_maps);
 DEFINE_MAP_OF_MAP(BPF_MAP_TYPE_HASH_OF_MAPS, lru_hash_map, hash_of_lru_hash_maps);
 
-extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
-extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
-void bpf_kfunc_call_test_ref(struct prog_test_ref_kfunc *p) __ksym;
-
 #define WRITE_ONCE(x, val) ((*(volatile typeof(x) *) &(x)) = (val))
 
 static void test_kptr_unref(struct map_value *v)
diff --git a/tools/testing/selftests/bpf/progs/map_kptr_fail.c b/tools/testing/selftests/bpf/progs/map_kptr_fail.c
index da8c724f839b..450bb373b179 100644
--- a/tools/testing/selftests/bpf/progs/map_kptr_fail.c
+++ b/tools/testing/selftests/bpf/progs/map_kptr_fail.c
@@ -4,6 +4,7 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_core_read.h>
 #include "bpf_misc.h"
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 struct map_value {
 	char buf[8];
@@ -19,9 +20,6 @@ struct array_map {
 	__uint(max_entries, 1);
 } array_map SEC(".maps");
 
-extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
-extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
-
 SEC("?tc")
 __failure __msg("kptr access size must be BPF_DW")
 int size_not_bpf_dw(struct __sk_buff *ctx)
diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index 793689dcc170..4d582cac2c09 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -11,7 +11,6 @@
 #include <signal.h>
 #include <string.h>
 #include <execinfo.h> /* backtrace */
-#include <linux/membarrier.h>
 #include <sys/sysinfo.h> /* get_nprocs */
 #include <netinet/in.h>
 #include <sys/select.h>
@@ -629,68 +628,6 @@ out:
 	return err;
 }
 
-static int finit_module(int fd, const char *param_values, int flags)
-{
-	return syscall(__NR_finit_module, fd, param_values, flags);
-}
-
-static int delete_module(const char *name, int flags)
-{
-	return syscall(__NR_delete_module, name, flags);
-}
-
-/*
- * Trigger synchronize_rcu() in kernel.
- */
-int kern_sync_rcu(void)
-{
-	return syscall(__NR_membarrier, MEMBARRIER_CMD_SHARED, 0, 0);
-}
-
-static void unload_bpf_testmod(void)
-{
-	if (kern_sync_rcu())
-		fprintf(env.stderr, "Failed to trigger kernel-side RCU sync!\n");
-	if (delete_module("bpf_testmod", 0)) {
-		if (errno == ENOENT) {
-			if (verbose())
-				fprintf(stdout, "bpf_testmod.ko is already unloaded.\n");
-			return;
-		}
-		fprintf(env.stderr, "Failed to unload bpf_testmod.ko from kernel: %d\n", -errno);
-		return;
-	}
-	if (verbose())
-		fprintf(stdout, "Successfully unloaded bpf_testmod.ko.\n");
-}
-
-static int load_bpf_testmod(void)
-{
-	int fd;
-
-	/* ensure previous instance of the module is unloaded */
-	unload_bpf_testmod();
-
-	if (verbose())
-		fprintf(stdout, "Loading bpf_testmod.ko...\n");
-
-	fd = open("bpf_testmod.ko", O_RDONLY);
-	if (fd < 0) {
-		fprintf(env.stderr, "Can't find bpf_testmod.ko kernel module: %d\n", -errno);
-		return -ENOENT;
-	}
-	if (finit_module(fd, "", 0)) {
-		fprintf(env.stderr, "Failed to load bpf_testmod.ko into the kernel: %d\n", -errno);
-		close(fd);
-		return -EINVAL;
-	}
-	close(fd);
-
-	if (verbose())
-		fprintf(stdout, "Successfully loaded bpf_testmod.ko.\n");
-	return 0;
-}
-
 /* extern declarations for test funcs */
 #define DEFINE_TEST(name)				\
 	extern void test_##name(void) __weak;		\
@@ -1720,9 +1657,14 @@ int main(int argc, char **argv)
 	env.stderr = stderr;
 
 	env.has_testmod = true;
-	if (!env.list_test_names && load_bpf_testmod()) {
-		fprintf(env.stderr, "WARNING! Selftests relying on bpf_testmod.ko will be skipped.\n");
-		env.has_testmod = false;
+	if (!env.list_test_names) {
+		/* ensure previous instance of the module is unloaded */
+		unload_bpf_testmod(verbose());
+
+		if (load_bpf_testmod(verbose())) {
+			fprintf(env.stderr, "WARNING! Selftests relying on bpf_testmod.ko will be skipped.\n");
+			env.has_testmod = false;
+		}
 	}
 
 	/* initializing tests */
@@ -1819,7 +1761,7 @@ int main(int argc, char **argv)
 	close(env.saved_netns_fd);
 out:
 	if (!env.list_test_names && env.has_testmod)
-		unload_bpf_testmod();
+		unload_bpf_testmod(verbose());
 
 	free_test_selector(&env.test_selector);
 	free_test_selector(&env.subtest_selector);
diff --git a/tools/testing/selftests/bpf/test_progs.h b/tools/testing/selftests/bpf/test_progs.h
index 0ed3134333d4..77bd492c6024 100644
--- a/tools/testing/selftests/bpf/test_progs.h
+++ b/tools/testing/selftests/bpf/test_progs.h
@@ -405,7 +405,6 @@ static inline void *u64_to_ptr(__u64 ptr)
 int bpf_find_map(const char *test, struct bpf_object *obj, const char *name);
 int compare_map_keys(int map1_fd, int map2_fd);
 int compare_stack_ips(int smap_fd, int amap_fd, int stack_trace_len);
-int kern_sync_rcu(void);
 int trigger_module_test_read(int read_sz);
 int trigger_module_test_write(int write_sz);
 int write_sysctl(const char *sysctl, const char *value);
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index e4657c5bc3f1..71704a38cac3 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -40,6 +40,7 @@
 #include "bpf_util.h"
 #include "test_btf.h"
 #include "../../../include/linux/filter.h"
+#include "testing_helpers.h"
 
 #ifndef ENOTSUPP
 #define ENOTSUPP 524
@@ -873,8 +874,140 @@ static int create_map_kptr(void)
 	return fd;
 }
 
+static void set_root(bool set)
+{
+	__u64 caps;
+
+	if (set) {
+		if (cap_enable_effective(1ULL << CAP_SYS_ADMIN, &caps))
+			perror("cap_disable_effective(CAP_SYS_ADMIN)");
+	} else {
+		if (cap_disable_effective(1ULL << CAP_SYS_ADMIN, &caps))
+			perror("cap_disable_effective(CAP_SYS_ADMIN)");
+	}
+}
+
+static __u64 ptr_to_u64(const void *ptr)
+{
+	return (uintptr_t) ptr;
+}
+
+static struct btf *btf__load_testmod_btf(struct btf *vmlinux)
+{
+	struct bpf_btf_info info;
+	__u32 len = sizeof(info);
+	struct btf *btf = NULL;
+	char name[64];
+	__u32 id = 0;
+	int err, fd;
+
+	/* Iterate all loaded BTF objects and find bpf_testmod,
+	 * we need SYS_ADMIN cap for that.
+	 */
+	set_root(true);
+
+	while (true) {
+		err = bpf_btf_get_next_id(id, &id);
+		if (err) {
+			if (errno == ENOENT)
+				break;
+			perror("bpf_btf_get_next_id failed");
+			break;
+		}
+
+		fd = bpf_btf_get_fd_by_id(id);
+		if (fd < 0) {
+			if (errno == ENOENT)
+				continue;
+			perror("bpf_btf_get_fd_by_id failed");
+			break;
+		}
+
+		memset(&info, 0, sizeof(info));
+		info.name_len = sizeof(name);
+		info.name = ptr_to_u64(name);
+		len = sizeof(info);
+
+		err = bpf_obj_get_info_by_fd(fd, &info, &len);
+		if (err) {
+			close(fd);
+			perror("bpf_obj_get_info_by_fd failed");
+			break;
+		}
+
+		if (strcmp("bpf_testmod", name)) {
+			close(fd);
+			continue;
+		}
+
+		btf = btf__load_from_kernel_by_id_split(id, vmlinux);
+		if (!btf) {
+			close(fd);
+			break;
+		}
+
+		/* We need the fd to stay open so it can be used in fd_array.
+		 * The final cleanup call to btf__free will free btf object
+		 * and close the file descriptor.
+		 */
+		btf__set_fd(btf, fd);
+		break;
+	}
+
+	set_root(false);
+	return btf;
+}
+
+static struct btf *testmod_btf;
+static struct btf *vmlinux_btf;
+
+static void kfuncs_cleanup(void)
+{
+	btf__free(testmod_btf);
+	btf__free(vmlinux_btf);
+}
+
+static void fixup_prog_kfuncs(struct bpf_insn *prog, int *fd_array,
+			      struct kfunc_btf_id_pair *fixup_kfunc_btf_id)
+{
+	/* Patch in kfunc BTF IDs */
+	while (fixup_kfunc_btf_id->kfunc) {
+		int btf_id = 0;
+
+		/* try to find kfunc in kernel BTF */
+		vmlinux_btf = vmlinux_btf ?: btf__load_vmlinux_btf();
+		if (vmlinux_btf) {
+			btf_id = btf__find_by_name_kind(vmlinux_btf,
+							fixup_kfunc_btf_id->kfunc,
+							BTF_KIND_FUNC);
+			btf_id = btf_id < 0 ? 0 : btf_id;
+		}
+
+		/* kfunc not found in kernel BTF, try bpf_testmod BTF */
+		if (!btf_id) {
+			testmod_btf = testmod_btf ?: btf__load_testmod_btf(vmlinux_btf);
+			if (testmod_btf) {
+				btf_id = btf__find_by_name_kind(testmod_btf,
+								fixup_kfunc_btf_id->kfunc,
+								BTF_KIND_FUNC);
+				btf_id = btf_id < 0 ? 0 : btf_id;
+				if (btf_id) {
+					/* We put bpf_testmod module fd into fd_array
+					 * and its index 1 into instruction 'off'.
+					 */
+					*fd_array = btf__fd(testmod_btf);
+					prog[fixup_kfunc_btf_id->insn_idx].off = 1;
+				}
+			}
+		}
+
+		prog[fixup_kfunc_btf_id->insn_idx].imm = btf_id;
+		fixup_kfunc_btf_id++;
+	}
+}
+
 static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
-			  struct bpf_insn *prog, int *map_fds)
+			  struct bpf_insn *prog, int *map_fds, int *fd_array)
 {
 	int *fixup_map_hash_8b = test->fixup_map_hash_8b;
 	int *fixup_map_hash_48b = test->fixup_map_hash_48b;
@@ -899,7 +1032,6 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
 	int *fixup_map_ringbuf = test->fixup_map_ringbuf;
 	int *fixup_map_timer = test->fixup_map_timer;
 	int *fixup_map_kptr = test->fixup_map_kptr;
-	struct kfunc_btf_id_pair *fixup_kfunc_btf_id = test->fixup_kfunc_btf_id;
 
 	if (test->fill_helper) {
 		test->fill_insns = calloc(MAX_TEST_INSNS, sizeof(struct bpf_insn));
@@ -1100,25 +1232,7 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
 		} while (*fixup_map_kptr);
 	}
 
-	/* Patch in kfunc BTF IDs */
-	if (fixup_kfunc_btf_id->kfunc) {
-		struct btf *btf;
-		int btf_id;
-
-		do {
-			btf_id = 0;
-			btf = btf__load_vmlinux_btf();
-			if (btf) {
-				btf_id = btf__find_by_name_kind(btf,
-								fixup_kfunc_btf_id->kfunc,
-								BTF_KIND_FUNC);
-				btf_id = btf_id < 0 ? 0 : btf_id;
-			}
-			btf__free(btf);
-			prog[fixup_kfunc_btf_id->insn_idx].imm = btf_id;
-			fixup_kfunc_btf_id++;
-		} while (fixup_kfunc_btf_id->kfunc);
-	}
+	fixup_prog_kfuncs(prog, fd_array, test->fixup_kfunc_btf_id);
 }
 
 struct libcap {
@@ -1445,6 +1559,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 	int run_errs, run_successes;
 	int map_fds[MAX_NR_MAPS];
 	const char *expected_err;
+	int fd_array[2] = { -1, -1 };
 	int saved_errno;
 	int fixup_skips;
 	__u32 pflags;
@@ -1458,7 +1573,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 	if (!prog_type)
 		prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
 	fixup_skips = skips;
-	do_test_fixup(test, prog_type, prog, map_fds);
+	do_test_fixup(test, prog_type, prog, map_fds, &fd_array[1]);
 	if (test->fill_insns) {
 		prog = test->fill_insns;
 		prog_len = test->prog_len;
@@ -1492,6 +1607,8 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 	else
 		opts.log_level = DEFAULT_LIBBPF_LOG_LEVEL;
 	opts.prog_flags = pflags;
+	if (fd_array[1] != -1)
+		opts.fd_array = &fd_array[0];
 
 	if ((prog_type == BPF_PROG_TYPE_TRACING ||
 	     prog_type == BPF_PROG_TYPE_LSM) && test->kfunc) {
@@ -1684,6 +1801,12 @@ static int do_test(bool unpriv, unsigned int from, unsigned int to)
 {
 	int i, passes = 0, errors = 0;
 
+	/* ensure previous instance of the module is unloaded */
+	unload_bpf_testmod(verbose);
+
+	if (load_bpf_testmod(verbose))
+		return EXIT_FAILURE;
+
 	for (i = from; i < to; i++) {
 		struct bpf_test *test = &tests[i];
 
@@ -1711,6 +1834,9 @@ static int do_test(bool unpriv, unsigned int from, unsigned int to)
 		}
 	}
 
+	unload_bpf_testmod(verbose);
+	kfuncs_cleanup();
+
 	printf("Summary: %d PASSED, %d SKIPPED, %d FAILED\n", passes,
 	       skips, errors);
 	return errors ? EXIT_FAILURE : EXIT_SUCCESS;
diff --git a/tools/testing/selftests/bpf/testing_helpers.c b/tools/testing/selftests/bpf/testing_helpers.c
index dc9595ade8de..8d994884c7b4 100644
--- a/tools/testing/selftests/bpf/testing_helpers.c
+++ b/tools/testing/selftests/bpf/testing_helpers.c
@@ -9,6 +9,7 @@
 #include <bpf/libbpf.h>
 #include "test_progs.h"
 #include "testing_helpers.h"
+#include <linux/membarrier.h>
 
 int parse_num_list(const char *s, bool **num_set, int *num_set_len)
 {
@@ -326,3 +327,63 @@ __u64 read_perf_max_sample_freq(void)
 	fclose(f);
 	return sample_freq;
 }
+
+static int finit_module(int fd, const char *param_values, int flags)
+{
+	return syscall(__NR_finit_module, fd, param_values, flags);
+}
+
+static int delete_module(const char *name, int flags)
+{
+	return syscall(__NR_delete_module, name, flags);
+}
+
+int unload_bpf_testmod(bool verbose)
+{
+	if (kern_sync_rcu())
+		fprintf(stdout, "Failed to trigger kernel-side RCU sync!\n");
+	if (delete_module("bpf_testmod", 0)) {
+		if (errno == ENOENT) {
+			if (verbose)
+				fprintf(stdout, "bpf_testmod.ko is already unloaded.\n");
+			return -1;
+		}
+		fprintf(stdout, "Failed to unload bpf_testmod.ko from kernel: %d\n", -errno);
+		return -1;
+	}
+	if (verbose)
+		fprintf(stdout, "Successfully unloaded bpf_testmod.ko.\n");
+	return 0;
+}
+
+int load_bpf_testmod(bool verbose)
+{
+	int fd;
+
+	if (verbose)
+		fprintf(stdout, "Loading bpf_testmod.ko...\n");
+
+	fd = open("bpf_testmod.ko", O_RDONLY);
+	if (fd < 0) {
+		fprintf(stdout, "Can't find bpf_testmod.ko kernel module: %d\n", -errno);
+		return -ENOENT;
+	}
+	if (finit_module(fd, "", 0)) {
+		fprintf(stdout, "Failed to load bpf_testmod.ko into the kernel: %d\n", -errno);
+		close(fd);
+		return -EINVAL;
+	}
+	close(fd);
+
+	if (verbose)
+		fprintf(stdout, "Successfully loaded bpf_testmod.ko.\n");
+	return 0;
+}
+
+/*
+ * Trigger synchronize_rcu() in kernel.
+ */
+int kern_sync_rcu(void)
+{
+	return syscall(__NR_membarrier, MEMBARRIER_CMD_SHARED, 0, 0);
+}
diff --git a/tools/testing/selftests/bpf/testing_helpers.h b/tools/testing/selftests/bpf/testing_helpers.h
index 98f09bbae86f..5312323881b6 100644
--- a/tools/testing/selftests/bpf/testing_helpers.h
+++ b/tools/testing/selftests/bpf/testing_helpers.h
@@ -1,5 +1,9 @@
 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
 /* Copyright (C) 2020 Facebook, Inc. */
+
+#ifndef __TESTING_HELPERS_H
+#define __TESTING_HELPERS_H
+
 #include <stdbool.h>
 #include <bpf/bpf.h>
 #include <bpf/libbpf.h>
@@ -25,3 +29,8 @@ int parse_test_list_file(const char *path,
 			 bool is_glob_pattern);
 
 __u64 read_perf_max_sample_freq(void);
+int load_bpf_testmod(bool verbose);
+int unload_bpf_testmod(bool verbose);
+int kern_sync_rcu(void);
+
+#endif /* __TESTING_HELPERS_H */