Commit 239f09e2 authored by Junjie Cao's avatar Junjie Cao Committed by Jakub Kicinski
Browse files

selftests: ptp: treat unsupported PHC operations as skip 

Some PTP hardware clock (PHC) devices may return -EOPNOTSUPP for
operations like settime, adjtime, or adjfreq. This commonly occurs
with timestamp-only PHC implementations that don't support full clock
control.

For background, syzbot previously exposed a crash risk when PTP clock
drivers lacked required callbacks[1]. Subsequent work[2] made callback
presence a registration requirement. As a result, some drivers (like
iwlwifi MVM/MLD[3]) now provide stub callbacks that return -EOPNOTSUPP
for unsupported operations.

When phc_ctl encounters such devices, the "Operation not supported"
error should be treated as a skip (device limitation) rather than a
test failure. This patch:
- Adds [SKIP] output handling in log_test()
- Detects "Operation not supported" from phc_ctl and returns ksft_skip
- Returns ksft_skip if all tests are skipped, preventing false-positive
  results when testing timestamp-only PHC implementations

Link: https://lore.kernel.org/netdev/20251028043216.1971292-1-junjie.cao@intel.com/ [1]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dfb073d32cac [2]
Link: https://lore.kernel.org/netdev/20251204123204.9316-1-ziyao@disroot.org/

 [3]
Signed-off-by: default avatarJunjie Cao <junjie.cao@intel.com>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260126061532.12532-2-junjie.cao@intel.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 166e664e

tools/testing/selftests/ptp/phc.sh

+37 −12
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ phc_sanity 


# Exit status to return at the end. Set in case one of the tests fails.

EXIT_STATUS=0

PASS_COUNT=0

# Per-test return value. Clear at the beginning of each test.

RET=0
@@ -68,12 +69,18 @@ log_test() 
{

	local test_name=$1



	if [[ $RET -eq $ksft_skip ]]; then

		printf "TEST: %-60s  [SKIP]\n" "$test_name"

		return 0

	fi



	if [[ $RET -ne 0 ]]; then

		EXIT_STATUS=1

		printf "TEST: %-60s  [FAIL]\n" "$test_name"

		return 1

	fi



	((PASS_COUNT++))

	printf "TEST: %-60s  [ OK ]\n" "$test_name"

	return 0

}
@@ -92,34 +99,49 @@ tests_run() 


settime_do()

{

	local res

	local res out



	res=$(phc_ctl $DEV set 0 wait 120.5 get 2> /dev/null \

		| awk '/clock time is/{print $5}' \

		| awk -F. '{print $1}')

	out=$(LC_ALL=C phc_ctl $DEV set 0 wait 120.5 get 2>&1)

	if [[ $? -ne 0 ]]; then

		if echo "$out" | grep -qi "Operation not supported"; then

			return $ksft_skip

		fi

		return 1

	fi

	res=$(echo "$out" | awk '/clock time is/{print $5}' | awk -F. '{print $1}')



	(( res == 120 ))

}



adjtime_do()

{

	local res

	local res out



	res=$(phc_ctl $DEV set 0 adj 10 get 2> /dev/null \

		| awk '/clock time is/{print $5}' \

		| awk -F. '{print $1}')

	out=$(LC_ALL=C phc_ctl $DEV set 0 adj 10 get 2>&1)

	if [[ $? -ne 0 ]]; then

		if echo "$out" | grep -qi "Operation not supported"; then

			return $ksft_skip

		fi

		return 1

	fi

	res=$(echo "$out" | awk '/clock time is/{print $5}' | awk -F. '{print $1}')



	(( res == 10 ))

}



adjfreq_do()

{

	local res

	local res out



	# Set the clock to be 1% faster

	res=$(phc_ctl $DEV freq 10000000 set 0 wait 100.5 get 2> /dev/null \

		| awk '/clock time is/{print $5}' \

		| awk -F. '{print $1}')

	out=$(LC_ALL=C phc_ctl $DEV freq 10000000 set 0 wait 100.5 get 2>&1)

	if [[ $? -ne 0 ]]; then

		if echo "$out" | grep -qi "Operation not supported"; then

			return $ksft_skip

		fi

		return 1

	fi

	res=$(echo "$out" | awk '/clock time is/{print $5}' | awk -F. '{print $1}')



	(( res == 101 ))

}
@@ -166,4 +188,7 @@ trap cleanup EXIT 


tests_run



if [[ $EXIT_STATUS -eq 0 && $PASS_COUNT -eq 0 ]]; then

	exit $ksft_skip

fi

exit $EXIT_STATUS