Re: [PATCH v4 00/15] qemu_iotests: improve debugging options

[Vladimir Sementsov-Ogievskiy]

20.05.2021 10:52, Emanuele Giuseppe Esposito wrote:
> This series adds the option to attach gdbserver and valgrind
> to the QEMU binary running in qemu_iotests.
> It also allows to redirect QEMU binaries output of the python tests
> to the stdout, instead of a log file.
>
> Patches 1-6 introduce the -gdb option to both python and bash tests,

Could you describe how to use it?

I often have to debug qemu iotests with gdb, and can say the following:

1. Test runs different qemu binaries (not only qemu, but also qemu-nbd, 
qemu-img, qemu-io)

2. Test can run qemu binaries several times, or even in parallel.

So, with a new option, how will I choice, which qemu (or qemu-nbd, etc) process 
I want to be attached to gdb?

Currently, I do the following: I recompile with  "sleep(15);" at the place where I want to attach, 
and start the test. During the sleep, I find the needed process in "ps aux" output and start 
"gdb -p PID".. Sometimes there may be troubles if the place where I inserted the sleep is triggered 
on another code path.

So, with new option, can my workflow be improved or not?

> 7-10 extend the already existing -valgrind flag to work also on
> python tests, and patch 11 introduces -p to enable logging to stdout.
>
> In particular, patches 1,5,10 focus on extending the QMP socket timers
> when using gdb/valgrind, otherwise the python tests will fail due to
> delays in the QMP responses.
>
> This series is tested on the previous serie
> "qemu-iotests: quality of life improvements"
> but independent from it, so it can be applied separately.
>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> ---
> v4:
> * Rename environment variable from GDB_QEMU to GDB_OPTIONS
> * This time test 297 (pylint) passes [Max]
> * Refactor the qmp_timer field in machine.py, and add a new
>    parameter in machine.py and subclasses constructor [John]
> * Add additional check in patch 4 to cover the case where
>    GDB_OPTIONS is empty
>
> Emanuele Giuseppe Esposito (15):
>    python: qemu: add timer parameter for qmp.accept socket
>    python: qemu: pass the wrapper field from QEMUQtestmachine to
>      QEMUMachine
>    docs/devel/testing: add debug section to the QEMU iotests chapter
>    qemu-iotests: add option to attach gdbserver
>    qemu-iotests: delay QMP socket timers
>    qemu_iotests: insert gdbserver command line as wrapper for qemu binary
>    qemu-iotests: add gdbserver option to script tests too
>    docs/devel/testing: add -gdb option to the debugging section of QEMU
>      iotests
>    qemu-iotests: extend the check script to support valgrind for python
>      tests
>    qemu-iotests: extent QMP socket timeout when using valgrind
>    qemu-iotests: allow valgrind to read/delete the generated log file
>    qemu-iotests: insert valgrind command line as wrapper for qemu binary
>    docs/devel/testing: add -valgrind option to the debug section of QEMU
>      iotests
>    qemu-iotests: add option to show qemu binary logs on stdout
>    docs/devel/testing: add -p option to the debug section of QEMU iotests
>
>   docs/devel/testing.rst        | 30 +++++++++++++++++++
>   python/qemu/machine.py        |  7 +++--
>   python/qemu/qtest.py          |  9 ++++--
>   tests/qemu-iotests/check      | 15 +++++++---
>   tests/qemu-iotests/common.rc  |  8 ++++-
>   tests/qemu-iotests/iotests.py | 56 +++++++++++++++++++++++++++++++----
>   tests/qemu-iotests/testenv.py | 25 ++++++++++++++--
>   7 files changed, 132 insertions(+), 18 deletions(-)


--
Best regards,
Vladimir