Re: [PATCH] tests/avocado/reverse_debugging: Disable the ppc64 tests by default

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

On Wed, Nov 15, 2023 at 07:23:01AM +0100, Thomas Huth wrote:
> On 15/11/2023 02.15, Nicholas Piggin wrote:
> > On Wed Nov 15, 2023 at 4:29 AM AEST, Thomas Huth wrote:
> > > On 14/11/2023 17.37, Philippe Mathieu-Daudé wrote:
> > > > On 14/11/23 17:31, Thomas Huth wrote:
> > > > > The tests seem currently to be broken. Disable them by default
> > > > > until someone fixes them.
> > > > > 
> > > > > Signed-off-by: Thomas Huth <thuth@redhat.com>
> > > > > ---
> > > > >    tests/avocado/reverse_debugging.py | 7 ++++---
> > > > >    1 file changed, 4 insertions(+), 3 deletions(-)
> > > > 
> > > > Similarly, I suspect https://gitlab.com/qemu-project/qemu/-/issues/1961
> > > > which has a fix ready:
> > > > https://lore.kernel.org/qemu-devel/20231110170831.185001-1-richard.henderson@linaro.org/
> > > > 
> > > > Maybe wait the fix gets in first?
> > > 
> > > No, I applied Richard's patch, but the problem persists. Does this test
> > > still work for you?
> > 
> > I bisected it to 1d4796cd008373 ("python/machine: use socketpair() for
> > console connections"),
> 
> Maybe John (who wrote that commit) can help?

I find it hard to believe this commit is a direct root cause of the
problem since all it does is change the QEMU startup sequence so that
instead of QEMU listening for a monitor connection, it is given a
pre-opened monitor connection.

At the very most that should affect the startup timing a little.

I notice all the reverse debugging tests have a skip on gitlab
with a comment:

    # unidentified gitlab timeout problem

this makes be suspicious that John's patch has merely made this
(henceforth undiagnosed) timeout more likely to ocurr.

> > which causes this halfway through the test:
> > 
> > 2023-11-15 10:37:04,600 stacktrace       L0045 ERROR| Traceback (most recent call last):
> > 2023-11-15 10:37:04,600 stacktrace       L0045 ERROR|   File "/home/npiggin/src/qemu/build/pyvenv/lib/python3.11/site-packages/avocado/core/decorators.py", line 90, in wrapper
> > 2023-11-15 10:37:04,600 stacktrace       L0045 ERROR|     return function(obj, *args, **kwargs)
> > 2023-11-15 10:37:04,600 stacktrace       L0045 ERROR|            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > 2023-11-15 10:37:04,600 stacktrace       L0045 ERROR|   File "/home/npiggin/src/qemu/build/tests/avocado/reverse_debugging.py", line 264, in test_ppc64_powernv
> > 2023-11-15 10:37:04,600 stacktrace       L0045 ERROR|     self.reverse_debugging()
> > 2023-11-15 10:37:04,600 stacktrace       L0045 ERROR|   File "/home/npiggin/src/qemu/build/tests/avocado/reverse_debugging.py", line 173, in reverse_debugging
> > 2023-11-15 10:37:04,600 stacktrace       L0045 ERROR|     g.cmd(b'c')
> > 2023-11-15 10:37:04,600 stacktrace       L0045 ERROR|   File "/home/npiggin/src/qemu/build/pyvenv/lib/python3.11/site-packages/avocado/utils/gdb.py", line 783, in cmd
> > 2023-11-15 10:37:04,600 stacktrace       L0045 ERROR|     response_payload = self.decode(result)
> > 2023-11-15 10:37:04,600 stacktrace       L0045 ERROR|                        ^^^^^^^^^^^^^^^^^^^
> > 2023-11-15 10:37:04,600 stacktrace       L0045 ERROR|   File "/home/npiggin/src/qemu/build/pyvenv/lib/python3.11/site-packages/avocado/utils/gdb.py", line 738, in decode
> > 2023-11-15 10:37:04,600 stacktrace       L0045 ERROR|     raise InvalidPacketError
> > 2023-11-15 10:37:04,600 stacktrace       L0045 ERROR| avocado.utils.gdb.InvalidPacketError
> > 2023-11-15 10:37:04,600 stacktrace       L0046 ERROR|
> > 
> > It doesn't always fail the same gdb command
> > (I saw a bc on line 182 as well). It seems to be receiving a
> > zero length response?
> > 
> > No idea what's happening or why ppc seems to be more fragile.
> > Or why changing console connection affects gdb connection?

With regards,
Daniel
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