Re: [Qemu-devel] [PATCH v2 2/7] iotests: exclude killed processes from running under Valgrind

[Kevin Wolf <kwolf@redhat.com>]

Am 11.06.2019 um 20:02 hat Andrey Shinkevich geschrieben:
> The Valgrind tool fails to manage its termination when QEMU raises the
> signal SIGKILL. Lets exclude such test cases from running under the
> Valgrind because there is no sense to check memory issues that way.
> 
> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>

I don't fully understand the reasoning here. Most interesting memory
access errors happen before a process terminates. (I'm not talking about
leaks here, but use-after-free, buffer overflows, uninitialised memory
etc.)

However, I do see that running these test cases with -valgrind ends in a
hang because the valgrind process keeps hanging around as a zombie
process and the test case doesn't reap it. I'm not exactly sure why that
is, but it looks more like a problem with the parent process (i.e. the
bash script).

If we can't figure out how to fix this, we can disable valgrind in these
cases, but I think the explanation needs to be different.

> diff --git a/tests/qemu-iotests/039 b/tests/qemu-iotests/039
> index 0d4e963..95115e2 100755
> --- a/tests/qemu-iotests/039
> +++ b/tests/qemu-iotests/039
> @@ -65,6 +65,7 @@ echo "== Creating a dirty image file =="
>  IMGOPTS="compat=1.1,lazy_refcounts=on"
>  _make_test_img $size
>  
> +VALGRIND_QEMU="" \
>  $QEMU_IO -c "write -P 0x5a 0 512" \
>           -c "sigraise $(kill -l KILL)" "$TEST_IMG" 2>&1 \
>      | _filter_qemu_io

I agree with Vladimir that setting VALGRIND_QEMU only once at the top of
the script is probably the better option.

Kevin