Re: [PATCH v4 13/15] selftests/mm: move hwpoison setup into run_test() and silence modprobe output for memory-failure category

[Zi Yan <ziy@nvidia.com>]

On 6 Apr 2026, at 5:19, Sayali Patil wrote:

> run_vmtests.sh contains special handling to ensure the hwpoison_inject
> module is available for the memory-failure tests. This logic was
> implemented outside of run_test(), making the setup category-specific
> but managed globally.
>
> Move the hwpoison_inject handling into run_test() and restrict it
> to the memory-failure category so that:
> 1. the module is checked and loaded only when memory-failure tests run,
> 2. the test is skipped if the module or the debugfs interface
> (/sys/kernel/debug/hwpoison/) is not available.
> 3. the module is unloaded after the test if it was loaded by the script.
>
> This localizes category-specific setup and makes the test flow
> consistent with other per-category preparations.
>
> While updating this logic, fix the module availability check.
> The script previously used:
>
> 	modprobe -R hwpoison_inject
>
> The -R option prints the resolved module name to stdout, causing every
> run to print:
>
> 	hwpoison_inject
>
> in the test output, even when no action is required, introducing
> unnecessary noise.
>
> Replace this with:
>
> 	modprobe -n hwpoison_inject
>
> which verifies that the module is loadable without producing output,
> keeping the selftest logs clean and consistent.
>
> Also, ensure that skipped tests do not override a previously recorded
> failure. A skipped test currently sets exitcode to ksft_skip even if a
> prior test has failed, which can mask failures in the final exit status.
> Update the logic to only set exitcode to ksft_skip when no failure has
> been recorded.
>
> Fixes: ff4ef2fbd101 ("selftests/mm: add memory failure anonymous page test")
> Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
> ---
>  tools/testing/selftests/mm/run_vmtests.sh | 52 ++++++++++++++---------
>  1 file changed, 33 insertions(+), 19 deletions(-)
>
> diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
> index afdcfd0d7cef..17c9bd910c47 100755
> --- a/tools/testing/selftests/mm/run_vmtests.sh
> +++ b/tools/testing/selftests/mm/run_vmtests.sh
> @@ -235,6 +235,7 @@ pretty_name() {
>  run_test() {
>  	if test_selected ${CATEGORY}; then
>  		local skip=0
> +		local LOADED_MOD=0

Can you rename it to LOADED_MEMORY_FAILURE_MOD to clarify its use?
Since now LOADED_MOD is visible for the entire run_test().
>
>  		# On memory constrainted systems some tests can fail to allocate hugepages.
>  		# perform some cleanup before the test for a higher success rate.
> @@ -250,6 +251,28 @@ run_test() {
>  			fi
>  		fi
>
> +		# Ensure hwpoison_inject is available for memory-failure tests
> +		if [ "${CATEGORY}" = "memory-failure" ]; then
> +			# Try to load hwpoison_inject if not present.
> +			HWPOISON_DIR=/sys/kernel/debug/hwpoison/
> +			if [ ! -d "$HWPOISON_DIR" ]; then
> +				if ! modprobe -n hwpoison_inject > /dev/null 2>&1; then
> +					echo "Module hwpoison_inject not found, skipping..." \
> +						| tap_prefix
> +					skip=1
> +				else
> +					modprobe hwpoison_inject > /dev/null 2>&1
> +					LOADED_MOD=1
> +					if [ ! -d "$HWPOISON_DIR" ]; then
> +						echo "hwpoison debugfs interface not present" \
> +							| tap_prefix
> +						skip=1
> +					fi
> +				fi
> +			fi
> +
> +		fi
> +
>  		local test=$(pretty_name "$*")
>  		local title="running $*"
>  		local sep=$(echo -n "$title" | tr "[:graph:][:space:]" -)
> @@ -261,6 +284,12 @@ run_test() {
>  		else
>  			local ret=$ksft_skip
>  		fi
> +
> +		# Unload hwpoison_inject if we loaded it
> +		if [ -n "${LOADED_MOD}" ]; then
> +			modprobe -r hwpoison_inject > /dev/null 2>&1
> +		fi
> +
>  		count_total=$(( count_total + 1 ))
>  		if [ $ret -eq 0 ]; then
>  			count_pass=$(( count_pass + 1 ))
> @@ -270,7 +299,9 @@ run_test() {
>  			count_skip=$(( count_skip + 1 ))
>  			echo "[SKIP]" | tap_prefix
>  			echo "ok ${count_total} ${test} # SKIP" | tap_output
> -			exitcode=$ksft_skip
> +			if [ $exitcode -eq 0 ]; then
> +				exitcode=$ksft_skip
> +			fi
>  		else
>  			count_fail=$(( count_fail + 1 ))
>  			echo "[FAIL]" | tap_prefix
> @@ -529,24 +560,7 @@ CATEGORY="page_frag" run_test ./test_page_frag.sh nonaligned
>
>  CATEGORY="rmap" run_test ./rmap
>
> -# Try to load hwpoison_inject if not present.
> -HWPOISON_DIR=/sys/kernel/debug/hwpoison/
> -if [ ! -d "$HWPOISON_DIR" ]; then
> -	if ! modprobe -q -R hwpoison_inject; then
> -		echo "Module hwpoison_inject not found, skipping..."
> -	else
> -		modprobe hwpoison_inject > /dev/null 2>&1
> -		LOADED_MOD=1
> -	fi
> -fi
> -
> -if [ -d "$HWPOISON_DIR" ]; then
> -	CATEGORY="memory-failure" run_test ./memory-failure
> -fi
> -
> -if [ -n "${LOADED_MOD}" ]; then
> -	modprobe -r hwpoison_inject > /dev/null 2>&1
> -fi
> +CATEGORY="memory-failure" run_test ./memory-failure
>
>  if [ "${HAVE_HUGEPAGES}" = 1 ]; then
>  	echo "$orig_nr_hugepgs" > /proc/sys/vm/nr_hugepages
> -- 

Otherwise, LGTM.

Reviewed-by: Zi Yan <ziy@nvidia.com>

Best Regards,
Yan, Zi