From: Jiayuan Chen <[email protected]> Previously I added a FIONREAD test for sockmap, but it can occasionally fail in CI [1].
The test sends 10 bytes in two segments (2 + 8). For UDP, FIONREAD only reports the length of the first datagram, not the total queued data. The original code used recv_timeout() expecting all 10 bytes, but under high system load, the second datagram may not yet be processed by the protocol stack, so recv would only return the first 2-byte datagram, causing a size mismatch failure. Fix this by receiving exactly the expected bytes (matching FIONREAD) in the first recv. The remaining datagram is then consumed in a second recv block, which is only reachable for UDP since TCP's expected already equals sizeof(buf). Test: ./test_progs -a sockmap_basic 410/1 sockmap_basic/sockmap create_update_free:OK ... Summary: 1/35 PASSED, 0 SKIPPED, 0 FAILED [1] https://github.com/kernel-patches/bpf/actions/runs/22919385910/job/66515395423 Cc: Jiayuan Chen <[email protected]> Fixes: 17e2ce02bf56 ("selftests/bpf: Add tests for FIONREAD and copied_seq") Signed-off-by: Jiayuan Chen <[email protected]> --- .../selftests/bpf/prog_tests/sockmap_basic.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c index dd3c757859f6b..d2846579285f2 100644 --- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c @@ -1298,10 +1298,23 @@ static void test_sockmap_multi_channels(int sotype) avail = wait_for_fionread(p1, expected, IO_TIMEOUT_SEC); ASSERT_EQ(avail, expected, "ioctl(FIONREAD) full return"); - recvd = recv_timeout(p1, rcv, sizeof(rcv), MSG_DONTWAIT, 1); - if (!ASSERT_EQ(recvd, sizeof(buf), "recv_timeout(p1)") || + recvd = recv_timeout(p1, rcv, expected, MSG_DONTWAIT, 1); + if (!ASSERT_EQ(recvd, expected, "recv_timeout(p1)") || !ASSERT_OK(memcmp(buf, rcv, recvd), "data mismatch")) goto end; + + /* process remaining data for udp if secondary data is available */ + expected = sizeof(buf) - expected; + if (expected) { + avail = wait_for_fionread(p1, expected, IO_TIMEOUT_SEC); + ASSERT_EQ(avail, expected, "second ioctl(FIONREAD) full return"); + + recvd = recv_timeout(p1, rcv, expected, MSG_DONTWAIT, 1); + if (!ASSERT_EQ(recvd, expected, "second recv_timeout(p1)") || + !ASSERT_OK(memcmp(buf + sizeof(buf) - expected, rcv, recvd), + "second data mismatch")) + goto end; + } end: if (c0 >= 0) close(c0); -- 2.43.0
