Re: [PATCH net-next 1/3] selftests: drv-net: iou-zcrx: wait for memory provider cleanup

[David Wei <dw@davidwei.uk>]

On 2026-02-27 09:13, Jakub Kicinski wrote:
> io_uring defers zcrx context teardown to the iou_exit workqueue.
> 
>    # ps aux | grep iou
>    ...    07:58   0:00 [kworker/u19:0-iou_exit]
>    ... 07:58   0:00 [kworker/u18:2-iou_exit]
> 
> When the test's receiver process exits, bkg() returns but the memory
> provider may still be attached to the rx queue. The subsequent defer()
> that restores tcp-data-split then fails:
> 
>    # Exception while handling defer / cleanup (callback 3 of 3)!
>    # Defer Exception| net.ynl.pyynl.lib.ynl.NlError:
>        Netlink error: can't disable tcp-data-split while device has
>                       memory provider enabled: Invalid argument
>    not ok 1 iou-zcrx.test_zcrx.single
> 
> Add a helper that polls netdev queue-get until no rx queue reports
> the io-uring memory provider attribute. Register it as a defer()
> just before tcp-data-split is restored as a "barrier".
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
> CC: shuah@kernel.org
> CC: dw@davidwei.uk
> CC: jdamato@fastly.com
> CC: linux-kselftest@vger.kernel.org
> ---
>   .../selftests/drivers/net/hw/iou-zcrx.py       | 18 +++++++++++++++++-
>   1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/drivers/net/hw/iou-zcrx.py b/tools/testing/selftests/drivers/net/hw/iou-zcrx.py
> index c63d6d6450d2..c27c2064701d 100755
> --- a/tools/testing/selftests/drivers/net/hw/iou-zcrx.py
> +++ b/tools/testing/selftests/drivers/net/hw/iou-zcrx.py
> @@ -2,14 +2,27 @@
>   # SPDX-License-Identifier: GPL-2.0
>   
>   import re
> +import time
>   from os import path
>   from lib.py import ksft_run, ksft_exit, KsftSkipEx, ksft_variants, KsftNamedVariant
>   from lib.py import NetDrvEpEnv
>   from lib.py import bkg, cmd, defer, ethtool, rand_port, wait_port_listen
> -from lib.py import EthtoolFamily
> +from lib.py import EthtoolFamily, NetdevFamily
>   
>   SKIP_CODE = 42
>   
> +
> +def mp_clear_wait(cfg):
> +    """Wait for io_uring memory providers to clear from all device queues."""
> +    deadline = time.time() + 5

This is potentially a very long time to wait if code is buggy, as I
found out when debugging netkit queue lease. How about reducing this to
say 1 second?