Re: [ndctl PATCH] test/cxl-poison.sh: test scanning past fully mapped partitions

[Alison Schofield <alison.schofield@intel.com>]

On Tue, Jun 30, 2026 at 09:42:02PM -0700, Alison Schofield wrote:
> Listing poison by memdev scans the unmapped tail of every partition.
> When an earlier partition is fully mapped, its tail is zero length, but
> the scan must continue to later partitions. A regression caused the
> scan to stop at the first fully-mapped partition, leaving later
> partitions unscanned.
> 
> Backstop that behavior with a test case that fully maps a memdev's RAM
> partition so its unmapped tail is zero length, then injects poison into
> the unmapped PMEM partition that follows. The PMEM poison is only
> reported if the scan continues past the fully-mapped RAM partition.
> 
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>
> ---
>  test/cxl-poison.sh | 40 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 40 insertions(+)
> 
> diff --git a/test/cxl-poison.sh b/test/cxl-poison.sh
> index 49aa1b68c5c1..a03e08084eb4 100644
> --- a/test/cxl-poison.sh
> +++ b/test/cxl-poison.sh
> @@ -219,6 +219,45 @@ test_poison_by_region_offset_negative()
>  	clear_poison "$region" "$large_offset" true
>  }
>  
> +# Backstop a driver fix where a fully mapped partition prematurely
> +# terminated the unmapped poison scan.
> +test_poison_unmapped_later_partition()
> +{
> +	local decoder ram_size pmem_dpa
> +
> +	check_min_kver "7.3" || return 0

DaveJ found this failing in 7.3-rc1.

It turns out the kernel fixup for this testcase is not yet
merged. I have just pushed a new ndctl pending branch with
this changed to 7.4.

The kernel fixup is in this patchset from RichardC:
https://lore.kernel.org/linux-cxl/20260826014508.9989-1-icheng@nvidia.com/

There is no issue with the patch, it's just bad luck that it is stuck
in a Sashiko set of cleanups.

-- Alison


> +
> +	# Free the auto region to use the ram capacity
> +	$CXL destroy-region -f -b "$CXL_TEST_BUS" all
> +
> +	find_memdev
> +
> +	# Fully map the ram partition so it has a zero-length unmapped tail
> +	decoder=$($CXL list -b "$CXL_TEST_BUS" -D -d root -m "$memdev" |
> +		  jq -r ".[] |
> +		  select(.volatile_capable == true) |
> +		  select(.nr_targets == 1) |
> +		  .decoder")
> +	[[ -n "$decoder" && "$decoder" != "null" ]] ||
> +		do_skip "no x1 volatile decoder found"
> +
> +	ram_size=$($CXL list -m "$memdev" | jq -r ".[0].ram_size")
> +	[[ -n "$ram_size" && "$ram_size" != "null" ]] || err "$LINENO"
> +
> +	region=$($CXL create-region -t ram -d "$decoder" -m "$memdev" \
> +		 -s "$ram_size" | jq -r ".region")
> +	[[ -n "$region" && "$region" != "null" ]] || err "$LINENO"
> +
> +	# Poison the unmapped pmem tail
> +	pmem_dpa=$ram_size
> +	inject_poison "$memdev" "$pmem_dpa"
> +	validate_poison_found "-m $memdev" 1
> +	clear_poison "$memdev" "$pmem_dpa"
> +	validate_poison_found "-m $memdev" 0
> +
> +	$CXL destroy-region -f -b "$CXL_TEST_BUS" "$region"
> +}
> +
>  is_unaligned() {
>  	local region=$1
>  	local hbiw=$2
> @@ -332,6 +371,7 @@ run_poison_test()
>  		do_skip "test cases requires inject by region kernel support"
>  	test_poison_by_region_offset
>  	test_poison_by_region_offset_negative
> +	test_poison_unmapped_later_partition
>  }
>  
>  modprobe -r cxl_test
> 
> base-commit: 15e932c4e1318a9608ad9b799ad83a32a8b5970d
> -- 
> 2.37.3
>