Re: [PATCH 3/3] selftests: ublk: add test to verify that feat_map is complete

[Ming Lei <ming.lei@redhat.com>]

On Tue, Sep 16, 2025 at 04:05:57PM -0600, Uday Shankar wrote:
> Add a test that verifies that the currently running kernel does not
> report support for any features that are unrecognized by kublk. This
> should catch cases where features are added without updating kublk's
> feat_map accordingly, which has happened multiple times in the past (see
> [1], [2]).
> 
> Note that this new test may fail if the test suite is older than the
> kernel, and the newer kernel contains a newly introduced feature. I
> believe this is not a use case we currently care about - we only care
> about newer test suites passing on older kernels.
> 
> [1] https://lore.kernel.org/linux-block/20250606214011.2576398-1-csander@purestorage.com/t/#u
> [2] https://lore.kernel.org/linux-block/2a370ab1-d85b-409d-b762-f9f3f6bdf705@nvidia.com/t/#m1c520a058448d594fd877f07804e69b28908533f
> 
> Signed-off-by: Uday Shankar <ushankar@purestorage.com>
> ---
>  tools/testing/selftests/ublk/Makefile           |  1 +
>  tools/testing/selftests/ublk/test_generic_13.sh | 16 ++++++++++++++++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/tools/testing/selftests/ublk/Makefile b/tools/testing/selftests/ublk/Makefile
> index 5d7f4ecfb81612f919a89eb442f948d6bfafe225..770269efe42ab460366485ccc80abfa145a0c57b 100644
> --- a/tools/testing/selftests/ublk/Makefile
> +++ b/tools/testing/selftests/ublk/Makefile
> @@ -20,6 +20,7 @@ TEST_PROGS += test_generic_09.sh
>  TEST_PROGS += test_generic_10.sh
>  TEST_PROGS += test_generic_11.sh
>  TEST_PROGS += test_generic_12.sh
> +TEST_PROGS += test_generic_13.sh
>  
>  TEST_PROGS += test_null_01.sh
>  TEST_PROGS += test_null_02.sh
> diff --git a/tools/testing/selftests/ublk/test_generic_13.sh b/tools/testing/selftests/ublk/test_generic_13.sh
> new file mode 100755
> index 0000000000000000000000000000000000000000..ff5f22b078ddd08bc19f82aa66da6a44fa073f6f
> --- /dev/null
> +++ b/tools/testing/selftests/ublk/test_generic_13.sh
> @@ -0,0 +1,16 @@
> +#!/bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +
> +. "$(cd "$(dirname "$0")" && pwd)"/test_common.sh
> +
> +TID="generic_13"
> +ERR_CODE=0
> +
> +_prep_test "null" "check that feature list is complete"
> +
> +if ${UBLK_PROG} features | grep -q unknown; then
> +        ERR_CODE=255
> +fi
> +
> +_cleanup_test "null"
> +_show_result $TID $ERR_CODE

What if the ublk selftest is run on downstream kernel?

Maybe the output can changed to "unsupported" to show that ublk selftest
code doesn't cover or use this feature.



Thanks,
Ming