Hi,

On 11/2/2021 10:14 AM, Joe Burton wrote:

From: Joe Burton <redacted>

Add selftests verifying that each supported map type is traced.

Signed-off-by: Joe Burton <redacted>
---
 .../selftests/bpf/prog_tests/map_trace.c      | 166 ++++++++++++++++++
 .../selftests/bpf/progs/bpf_map_trace.c       |  95 ++++++++++
 .../bpf/progs/bpf_map_trace_common.h          |  12 ++
 3 files changed, 273 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/map_trace.c
 create mode 100644 tools/testing/selftests/bpf/progs/bpf_map_trace.c
 create mode 100644 tools/testing/selftests/bpf/progs/bpf_map_trace_common.h

snip

+	/*
+	 * Invoke core BPF program.
+	 */
+	write_fd = open("/tmp/map_trace_test_file", O_CREAT | O_WRONLY);
+	if (!ASSERT_GE(rc, 0, "open tmp file for writing"))
+		goto out;
+
+	bytes_written = write(write_fd, &write_buf, sizeof(write_buf));
+	if (!ASSERT_EQ(bytes_written, sizeof(write_buf), "write to tmp file"))
+		return;

In fentry__x64_sys_write(), you just do trigger updates to maps, so for the
portability of the test
(e.g. run-able for arm64) and minimal dependency (e.g. don't depends on /tmp),
why do you
using nanosleep() and replacing fentry_x64_sys_write by
tp/syscalls/sys_enter_nanosleep instead.
Also it will be better if you can filter out other processes by pid.

Thanks,
Tao