CFS Fatal Error

[LeStarch]

F´ Version
Affected Component

---

Problem Description

There is a FATAL assert in cFS code that is included in CFDP with large file uplink and downlink

Context / Environment

@yvijay99

How to Reproduce

@yvijay99

[LeStarch]

Blocked on #5138

[yvijay99]

F´ Version
v4.2.0-551-g6dcb9925d, on the pr-5138 branch (nasa/fprime#5138).

Affected Component
Svc/Ccsds/CfdpManager

Specifically Svc/Ccsds/CfdpManager/Clist.cpp, in CfdpCListTraverse (line 170) and CfdpCListTraverseR (line 210).

Problem Description
The test I ran

An integration test that uploads a 1 MiB file over CFDP Class 2, from fprime-yamcs-reference on branch testingcfdpyamcs:

def test_cfdp_large_file_upload(fprime_test_api: IntegrationTestAPI):
    """1 MiB Class 2 upload, exercising multi-PDU segmentation.

    maxPduSize is 992 bytes, so this file spans roughly 1100 PDUs and is the
    only test that meaningfully exercises segmentation, gap tracking and NAK
    handling rather than a single-PDU transfer.
    """
    yamcs_client = _require_yamcs(fprime_test_api)
    configure_cfdp_entity_ids(fprime_test_api, local_eid=42)

    file_size = 1024 * 1024
    local_path = _make_file(b"A" * file_size, suffix=".bin")
    destination = f"/tmp/big_{random.randint(0, 10000)}.bin"

    try:
        start = fprime_test_api.get_event_test_history().size()
        _assert_completed(
            _upload(yamcs_client, local_path, destination, reliable=True, timeout=300),
            "Large upload",
        )

        event = fprime_test_api.await_event(
            fprime_test_api.get_mnemonic(CFDP_MANAGER) + ".RxFileTransferCompleted",
            start=start,
            timeout=300,
        )
        args = _transfer_event_args(event)
        assert int(args["fileSize"]) == file_size, (
            f"Spacecraft received {args['fileSize']} bytes, expected {file_size}"
        )
    finally:
        _cleanup(fprime_test_api, [local_path], [destination])

Intent

maxPduSize is 992 bytes, so a 1 MiB file spans roughly 1100 PDUs. This is the only test in the suite that exercises segmentation, gap tracking and NAK handling. Every other test transfers a file that fits in a single PDU.

What is supposed to happen

The file transfers, RxFileTransferCompleted reports 1048576 bytes, and the suite continues to the next test.

What actually happens

A FATAL assert fires during the run:

AF_ASSERT_1: Assert in file Svc/Ccsds/CfdpManager/Clist.cpp, line 170: 0
Arguments: {'file': '.../Svc/Ccsds/CfdpManager/Clist.cpp', 'line': '170', 'arg1': '0'}

Running the suite without this test, everything passes. Adding it back reproduces the assert.

Where the bug is (I think)

Svc/Ccsds/CfdpManager/Clist.cpp, lines 150 to 170:

for (i = 0; i < maxIterations && !last; ++i) {
    node_next = node->next;
    if (node_next == start) {
        last = true;
    }
    if (!CfdpCListTraverseStatusIsContinue(fn(node, context))) {
        break;
    }
    ...
    node = node_next;
}
FW_ASSERT(last, static_cast<FwAssertArgType>(i));   // line 170

The assert on line 170 demands that last be true. But break exits without ever setting last. So ending the loop the second way trips the assert.

Context / Environment

F´ v4.2.0-551-g6dcb9925d, branch pr-5138
Deployment: fprime-yamcs-reference, branch testingcfdpyamcs, FprimeYamcsReference/YamcsDeployment
Host: macOS (Darwin), native build
Ground system: YAMCS 5.12.0 with org.yamcs.cfdp.CfdpService, maxPduSize: 992, entity IDs YAMCS 100 and F´ 42
Stock config/CfdpCfg.hpp, so CFDP_MAX_SIMULTANEOUS_RX = 5 and maxIterations = 50
FW_ASSERT_LEVEL at its default of FW_FILENAME_ASSERT, so asserts are active

How to Reproduce

1. Build and run FprimeYamcsReference/YamcsDeployment against YAMCS with CFDP configured, maxPduSize: 992.
   Use the following PRs (TBD)
2. Run the CFDP integration suite including the 1 MiB Class 2 upload above.
3. AF_ASSERT_1 fires from Clist.cpp:170 with arg1: 0.
4. Removing the 1 MiB test from the suite makes the assert disappear.