From: Mykyta Yatsenko file_reader/on_open_expect_fault intermittently fails when test_progs runs tests in parallel, because it expects a page fault on first read. Another file_reader test running concurrently may have already pulled the same pages into the page cache, eliminating the fault and causing a spurious failure. Make file_reader/on_open_expect_fault read from a file region that does not overlap with other file_reader tests, so the initial access still faults even under parallel execution. Signed-off-by: Mykyta Yatsenko --- tools/testing/selftests/bpf/prog_tests/file_reader.c | 6 +++++- tools/testing/selftests/bpf/progs/file_reader.c | 2 +- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/file_reader.c b/tools/testing/selftests/bpf/prog_tests/file_reader.c index 2a034d43b73e..5cde32b35da4 100644 --- a/tools/testing/selftests/bpf/prog_tests/file_reader.c +++ b/tools/testing/selftests/bpf/prog_tests/file_reader.c @@ -52,7 +52,11 @@ static int initialize_file_contents(void) /* page-align base file address */ addr = (void *)((unsigned long)addr & ~(page_sz - 1)); - for (off = 0; off < sizeof(file_contents); off += page_sz) { + /* + * Page out range 0..512K, use 0..256K for positive tests and + * 256K..512K for negative tests expecting page faults + */ + for (off = 0; off < sizeof(file_contents) * 2; off += page_sz) { if (!ASSERT_OK(madvise(addr + off, page_sz, MADV_PAGEOUT), "madvise pageout")) return errno; diff --git a/tools/testing/selftests/bpf/progs/file_reader.c b/tools/testing/selftests/bpf/progs/file_reader.c index 2585f83b0ce5..166c3ac6957d 100644 --- a/tools/testing/selftests/bpf/progs/file_reader.c +++ b/tools/testing/selftests/bpf/progs/file_reader.c @@ -49,7 +49,7 @@ int on_open_expect_fault(void *c) if (bpf_dynptr_from_file(file, 0, &dynptr)) goto out; - local_err = bpf_dynptr_read(tmp_buf, user_buf_sz, &dynptr, 0, 0); + local_err = bpf_dynptr_read(tmp_buf, user_buf_sz, &dynptr, user_buf_sz, 0); if (local_err == -EFAULT) { /* Expect page fault */ local_err = 0; run_success = 1; -- 2.51.1