mattgorringe

Hi Can someone take look at this call stack and threadlock that appears to happen very occasionally with our app on one VM.

I have not been able to reproduce on a dev machine.

We are using amBlocking for the firedac query but getting a call to check synchronize twice where we get a threadlock on second one.

This is main thread.

Have checked the 22.0 code and no changes this is from v19.0, procedure in FireDAC.Stan.Async:

procedure TFDStanAsyncExecutor.Run

Here is the offending code:

                    else if (FMode = amNonBlocking) or not (
                        (rMsg.message >= WM_KEYDOWN) and (rMsg.message <= WM_DEADCHAR) and
                          ((FAsyncDlg = nil) or not FAsyncDlg.IsFormActive) or
                        (rMsg.message >= WM_MOUSEFIRST) and (rMsg.message <= WM_MOUSELAST) and
                          ((FAsyncDlg = nil) or not FAsyncDlg.IsFormMouseMessage(rMsg)) or
                        (rMsg.message >= WM_SYSKEYDOWN) and (rMsg.message <= WM_SYSDEADCHAR)
                       ) then begin
                      TranslateMessage(rMsg);
                      DispatchMessage(rMsg);
                    end;

To fix im proposing to add in this to the above code block so messages can not be processed with amBlocking.

if FMode <> amBlocking then

Anyone else seen this behavior?

Now also it could be possible for a threadlock if we were using amNonBlocking from what i can see - that would also be bad.