Re: tests/qtest: Is vnc-display-test supposed to work on Darwin?

["Daniel P. Berrangé" <berrange@redhat.com>]

On Thu, Jan 19, 2023 at 12:21:58PM +0100, Philippe Mathieu-Daudé wrote:
> On 19/1/23 12:16, Daniel P. Berrangé wrote:
> > On Thu, Jan 19, 2023 at 12:01:18PM +0100, Philippe Mathieu-Daudé wrote:
> > > On 5/12/22 08:51, Marc-André Lureau wrote:
> > > > On Fri, Dec 2, 2022 at 1:51 PM Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
> > > > > 
> > > > > The vnc-display-test is failing on Darwin:
> > > > > 
> > > > > tests/qtest/vnc-display-test:45038): ERROR **: 10:42:35.488: vnc-error:
> > > > > Unsupported auth type 17973672
> > > > 
> > > > It is supposed to pass. Can you share more details? It doesn't look
> > > > like an endianness issue, at first sight..
> > > 
> > > Adding '-trace vnc*' and setting _VNC_DEBUG in "vnc.h" I get:
> 
> > > Bail out! FATAL-ERROR: vnc-error: Unsupported auth type 5489072
> > 
> > ^^^^ This specific message is comnig from the gtk-vnc client rather
> > than QEMU
> > 
> > Still doesn't tell us if the flaw is server or client side. The
> > logs from QEMU are insufficient. In theory it should be reporting
> > auth type == 0 though, for 'no auth' configs.
> 
> > > Does that help? What else can I do to gather more info?
> > 
> > Modify vnc-display-test.c to call  vnc_util_set_debug(TRUE);
> > before vnc_connection_new(), to get the gtk-vnc debug logs
> > to stderr too.
> Here you go:
> 
> vnc_server_dpy_recreate VNC server dpy recreate dpy=0x1588b8000 size=640x384
> fmt=537004168
> vnc_auth_init VNC auth init state=0x1588b8000 websock=0 auth=1 subauth=0
> vnc_auth_init VNC auth init state=0x1588b8000 websock=1 auth=1 subauth=0
> vnc_client_connect VNC client connect state=0x1484b0000 ioc=0x152e667f0
> # gtk-vnc-DEBUG: ../src/vncconnection.c Init VncConnection=0x14f0168b0
> gtk-vnc-DEBUG: 12:20:30.482: ../src/vncconnection.c Init
> VncConnection=0x14f0168b0
> # gtk-vnc-DEBUG: ../src/vncconnection.c Thinking about auth type 1
> gtk-vnc-DEBUG: 12:20:30.482: ../src/vncconnection.c Thinking about auth type
> 1
> # gtk-vnc-DEBUG: ../src/vncconnection.c Decided on auth type 1
> gtk-vnc-DEBUG: 12:20:30.482: ../src/vncconnection.c Decided on auth type 1

So here we set conn->auth_type == 1


> # gtk-vnc-DEBUG: ../src/vncconnection.c Open fd=4
> gtk-vnc-DEBUG: 12:20:30.482: ../src/vncconnection.c Open fd=4
> # gtk-vnc-DEBUG: ../src/vncconnection.c Open coroutine starting
> gtk-vnc-DEBUG: 12:20:30.482: ../src/vncconnection.c Open coroutine starting
> # gtk-vnc-DEBUG: ../src/vncconnection.c Started background coroutine
> gtk-vnc-DEBUG: 12:20:30.484: ../src/vncconnection.c Started background
> coroutine
> # gtk-vnc-DEBUG: ../src/vncconnection.c Connecting to FD 4
> gtk-vnc-DEBUG: 12:20:30.484: ../src/vncconnection.c Connecting to FD 4
> # gtk-vnc-DEBUG: ../src/vncconnection.c Emit main context 16
> gtk-vnc-DEBUG: 12:20:30.485: ../src/vncconnection.c Emit main context 16
> # gtk-vnc-DEBUG: ../src/vncconnection.c Protocol initialization
> gtk-vnc-DEBUG: 12:20:30.485: ../src/vncconnection.c Protocol initialization
> # gtk-vnc-DEBUG: ../src/vncconnection.c Schedule greeting timeout
> 0x14f0155e0
> gtk-vnc-DEBUG: 12:20:30.485: ../src/vncconnection.c Schedule greeting
> timeout 0x14f0155e0
> # gtk-vnc-DEBUG: ../src/vncconnection.c Remove timeout 0x14f0155e0
> gtk-vnc-DEBUG: 12:20:30.485: ../src/vncconnection.c Remove timeout
> 0x14f0155e0
> # gtk-vnc-DEBUG: ../src/vncconnection.c Server version: 3.8
> gtk-vnc-DEBUG: 12:20:30.485: ../src/vncconnection.c Server version: 3.8
> # gtk-vnc-DEBUG: ../src/vncconnection.c Sending full greeting
> gtk-vnc-DEBUG: 12:20:30.485: ../src/vncconnection.c Sending full greeting
> # gtk-vnc-DEBUG: ../src/vncconnection.c Using version: 3.8
> gtk-vnc-DEBUG: 12:20:30.485: ../src/vncconnection.c Using version: 3.8
> # gtk-vnc-DEBUG: ../src/vncconnection.c Possible auth 1
> gtk-vnc-DEBUG: 12:20:30.589: ../src/vncconnection.c Possible auth 1
> # gtk-vnc-DEBUG: ../src/vncconnection.c Emit main context 14
> gtk-vnc-DEBUG: 12:20:30.589: ../src/vncconnection.c Emit main context 14
> # gtk-vnc-DEBUG: ../src/vncconnection.c Waiting for auth type
> gtk-vnc-DEBUG: 12:20:30.589: ../src/vncconnection.c Waiting for auth type
> # gtk-vnc-DEBUG: ../src/vncconnection.c Choose auth 10486192

Here we've read conn->auth_type and got back 10486192 nonsense instead
of 1.

Interestingly this value is differetn from the previous debug log
which reported  5489072, so i guess we're getting garbage here for
unknown reasons.

This looks like a gtk-vnc problem rather than QEMU.

I'm a little worried that perhaps the gtk-vnc ucontext coroutine backend
is broken on macOS

What coroutine backend does QEMU end up using on macOS ? Is it the
sigaltstack one ?


With regards,
Daniel
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