[PATCH bpf-next v3 2/2] selftests/bpf: add a test for ptr_to_map_value on stack for helper access

[Yonghong Song <yhs@xxxxxx>]

Change bpf_iter_task.c such that pointer to map_value may appear
on the stack for bpf_seq_printf() to access. Without previous
verifier patch, the bpf_iter test will fail.

Acked-by: Song Liu <songliubraving@xxxxxx>
Signed-off-by: Yonghong Song <yhs@xxxxxx>
---
 tools/testing/selftests/bpf/progs/bpf_iter_task.c | 3 ++-
 tools/testing/selftests/bpf/verifier/unpriv.c     | 5 +++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_task.c b/tools/testing/selftests/bpf/progs/bpf_iter_task.c
index 4983087852a0..b7f32c160f4e 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_task.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_task.c
@@ -11,9 +11,10 @@ int dump_task(struct bpf_iter__task *ctx)
 {
 	struct seq_file *seq = ctx->meta->seq;
 	struct task_struct *task = ctx->task;
+	static char info[] = "    === END ===";
 
 	if (task == (void *)0) {
-		BPF_SEQ_PRINTF(seq, "    === END ===\n");
+		BPF_SEQ_PRINTF(seq, "%s\n", info);
 		return 0;
 	}
 
diff --git a/tools/testing/selftests/bpf/verifier/unpriv.c b/tools/testing/selftests/bpf/verifier/unpriv.c
index 91bb77c24a2e..a3fe0fbaed41 100644
--- a/tools/testing/selftests/bpf/verifier/unpriv.c
+++ b/tools/testing/selftests/bpf/verifier/unpriv.c
@@ -108,8 +108,9 @@
 	BPF_EXIT_INSN(),
 	},
 	.fixup_map_hash_8b = { 3 },
-	.errstr = "invalid indirect read from stack off -8+0 size 8",
-	.result = REJECT,
+	.errstr_unpriv = "invalid indirect read from stack off -8+0 size 8",
+	.result_unpriv = REJECT,
+	.result = ACCEPT,
 },
 {
 	"unpriv: mangle pointer on stack 1",
-- 
2.24.1