Add 3 test cases for skb dynptr used in tp_btf:
- test_dynptr_skb_tp_btf: use skb dynptr in tp_btf and make sure it is
   read-only.
- skb_invalid_ctx_fentry/skb_invalid_ctx_fexit: bpf_dynptr_from_skb
   should fail in fentry/fexit.

In test_dynptr_skb_tp_btf, to trigger the tracepoint in kfree_skb,
test_pkt_access is used for its test_run, as in kfree_skb.c. Because the
test process is different from others, a new setup type is defined,
i.e., SETUP_SKB_PROG_TP.

The result is like:
$ ./test_progs -t 'dynptr/test_dynptr_skb_tp_btf'
   #84/14   dynptr/test_dynptr_skb_tp_btf:OK
   #84      dynptr:OK
   #127     kfunc_dynptr_param:OK
   Summary: 2/1 PASSED, 0 SKIPPED, 0 FAILED

$ ./test_progs -t 'dynptr/skb_invalid_ctx_f'
   #84/85   dynptr/skb_invalid_ctx_fentry:OK
   #84/86   dynptr/skb_invalid_ctx_fexit:OK
   #84      dynptr:OK
   #127     kfunc_dynptr_param:OK
   Summary: 2/2 PASSED, 0 SKIPPED, 0 FAILED

Also fix two coding style nits (change spaces to tabs).

Signed-off-by: Philo Lu <lulie@linux.alibaba.com>
---
  .../testing/selftests/bpf/prog_tests/dynptr.c | 36 +++++++++++++++++--
  .../testing/selftests/bpf/progs/dynptr_fail.c | 25 +++++++++++++
  .../selftests/bpf/progs/dynptr_success.c      | 23 ++++++++++++
  3 files changed, 82 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/dynptr.c b/tools/testing/selftests/bpf/prog_tests/dynptr.c
index 7cfac53c0d58d..ba40be8b1c4ef 100644
--- a/tools/testing/selftests/bpf/prog_tests/dynptr.c
+++ b/tools/testing/selftests/bpf/prog_tests/dynptr.c

@@ -9,6 +9,7 @@
  enum test_setup_type {
  	SETUP_SYSCALL_SLEEP,
  	SETUP_SKB_PROG,
+	SETUP_SKB_PROG_TP,
  };
  
  static struct {

@@ -28,6 +29,7 @@ static struct {
  	{"test_dynptr_clone", SETUP_SKB_PROG},
  	{"test_dynptr_skb_no_buff", SETUP_SKB_PROG},
  	{"test_dynptr_skb_strcmp", SETUP_SKB_PROG},
+	{"test_dynptr_skb_tp_btf", SETUP_SKB_PROG_TP},
  };
  
  static void verify_success(const char *prog_name, enum test_setup_type setup_type)

@@ -35,7 +37,7 @@ static void verify_success(const char *prog_name, enum test_setup_type setup_typ
  	struct dynptr_success *skel;
  	struct bpf_program *prog;
  	struct bpf_link *link;
-       int err;
+	int err;
  
  	skel = dynptr_success__open();
  	if (!ASSERT_OK_PTR(skel, "dynptr_success__open"))

@@ -47,7 +49,7 @@ static void verify_success(const char *prog_name, enum test_setup_type setup_typ
  	if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
  		goto cleanup;
  
-       bpf_program__set_autoload(prog, true);
+	bpf_program__set_autoload(prog, true);
  
  	err = dynptr_success__load(skel);
  	if (!ASSERT_OK(err, "dynptr_success__load"))

@@ -87,6 +89,36 @@ static void verify_success(const char *prog_name, enum test_setup_type setup_typ
  
  		break;
  	}
+	case SETUP_SKB_PROG_TP:
+	{
+		struct __sk_buff skb = {};
+		struct bpf_object *obj;
+		int aux_prog_fd;
+
+		/* Just use its test_run to trigger kfree_skb tracepoint */
+		err = bpf_prog_test_load("./test_pkt_access.bpf.o", BPF_PROG_TYPE_SCHED_CLS,
+					 &obj, &aux_prog_fd);
+		if (!ASSERT_OK(err, "prog_load sched cls"))
+			goto cleanup;
+
+		LIBBPF_OPTS(bpf_test_run_opts, topts,
+			    .data_in = &pkt_v4,
+			    .data_size_in = sizeof(pkt_v4),
+			    .ctx_in = &skb,
+			    .ctx_size_in = sizeof(skb),
+		);
+
+		link = bpf_program__attach(prog);
+		if (!ASSERT_OK_PTR(link, "bpf_program__attach"))
+			goto cleanup;
+
+		err = bpf_prog_test_run_opts(aux_prog_fd, &topts);