Re: [PATCH net-next v7 3/3] selftests/net: devmem.py: add check_rx_large_niov

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The newly added rx_page_size probe in require_devmem() fails to execute within the correct network namespace, causing the test to incorrectly skip in containerized environments (like nk_devmem.py).
--

--- Patch [3]: [PATCH net-next v7 3/3] selftests/net: devmem.py: add check_rx_large_niov ---
commit 53558ad37aa9b0e02e2eb8a09081a53ab1fd981c
Author: Bobby Eshleman <bobbyeshleman@meta.com>

selftests/net: devmem.py: add check_rx_large_niov

Add a new devmem test case for binding the dmabuf with rx-page-size=16K.
The test sweeps RX payload sizes straddling the niov boundary to cover
the sub-niov, exact-niov, and multi-niov RX paths.

> diff --git a/tools/testing/selftests/drivers/net/hw/devmem_lib.py b/tools/testing/selftests/drivers/net/hw/devmem_lib.py
> index 0921ff03eb81c..cbe3a8e498239 100644
> --- a/tools/testing/selftests/drivers/net/hw/devmem_lib.py
> +++ b/tools/testing/selftests/drivers/net/hw/devmem_lib.py

[ ... ]

> @@ -18,6 +28,25 @@ def require_devmem(cfg):
>      if not cfg.devmem_supported:
>          raise KsftSkipEx("Test requires devmem support")
>  
> +    if rx_page_size > 0:
> +        page_size = os.sysconf("SC_PAGE_SIZE")
> +        if not _is_aligned(rx_page_size, page_size):
> +            raise KsftSkipEx(
> +                f"rx-page-size={rx_page_size} is invalid for this platform "
> +                f"(must be a multiple of PAGE_SIZE={page_size})")
> +
> +        if not hasattr(cfg, "devmem_rx_page_size_probed"):
> +            cfg.devmem_rx_page_size_probed = {}
> +
> +        if rx_page_size not in cfg.devmem_rx_page_size_probed:
> +            probe_command = f"{cfg.bin_local} -f {cfg.ifname} -b {rx_page_size}"
> +            cfg.devmem_rx_page_size_probed[rx_page_size] = \
> +                cmd(probe_command, fail=False, shell=True).ret == 0

[Severity: Medium]
Is it intentional that this probe command executes in the default namespace
rather than the containerized network namespace?

Since cmd() is called without the ns=getattr(cfg, "netns", None) argument,
it appears this probe runs outside of the proper network context. Could this
cause tests in container environments (like nk_devmem.py) to incorrectly skip
because the rx_page_size capability probe fails?

> +
> +        if not cfg.devmem_rx_page_size_probed[rx_page_size]:
> +            raise KsftSkipEx(
> +                f"Test requires devmem rx-page-size={rx_page_size} support")
> +

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260730-tcpdm-large-niovs-v7-0-033d580a619d@meta.com?part=3