Re: [PATCH v6 3/4] net: dropreason: use new __print_sym() in tracing

Ilya Maximets [off-list ref] writes:

On 9/22/26 1:20 AM, Johannes Berg wrote:

quoted

On Tue, 2026-09-22 at 00:36 +0200, Johannes Berg wrote:

quoted

Indeed. Something like this (untested right now, didn't manage to spin
up a test yet):

diff --git a/tools/testing/selftests/net/openvswitch/openvswitch.sh b/tools/testing/selftests/net/openvswitch/openvswitch.sh
index a31f7fb6882d..9b8edfcd2d1a 100755
--- a/tools/testing/selftests/net/openvswitch/openvswitch.sh
+++ b/tools/testing/selftests/net/openvswitch/openvswitch.sh

@@ -234,7 +234,7 @@ ovs_drop_reason_count()
 	local reason=$1
 
 	local perf_output=`perf script -i ${ovs_dir}/perf.data -F trace:event,trace`
-	local pattern="skb:kfree_skb:.*reason: $reason"
+	local pattern="skb:kfree_skb:.*reason: $reason$"
 
 	return `echo "$perf_output" | grep "$pattern" | wc -l`
 }

@@ -790,15 +790,6 @@ test_psample() {
 # - drop packets and verify the right drop reason is reported
 test_drop_reason() {
 	which perf >/dev/null 2>&1 || return $ksft_skip
-	which pahole >/dev/null 2>&1 || return $ksft_skip
-
-	ovs_drop_subsys=$(pahole -C skb_drop_reason_subsys |
-			      awk '/OPENVSWITCH/ { print $3; }' |
-			      tr -d ,)
-	if [ -z "$ovs_drop_subsys" ]; then
-		info "failed to get OVS drop subsys ID"
-		return $ksft_skip
-	fi
 
 	sbx_add "test_drop_reason" || return $?
 

@@ -842,7 +833,7 @@ test_drop_reason() {
 		"in_port(2),eth(),eth_type(0x0800),ipv4(src=172.31.110.20,proto=1),icmp()" 'drop'
 
 	ovs_drop_record_and_run "test_drop_reason" ip netns exec client ping -c 2 172.31.110.20
-	ovs_drop_reason_count 0x${ovs_drop_subsys}0001 # OVS_DROP_FLOW_ACTION
+	ovs_drop_reason_count OVS_DROP_LAST_ACTION
 	if [[ "$?" -ne "2" ]]; then
 		info "Did not detect expected drops: $?"
 		return 1

@@ -859,7 +850,7 @@ test_drop_reason() {
 
 	ovs_drop_record_and_run \
             "test_drop_reason" ip netns exec client nc -i 1 -zuv 172.31.110.20 6000
-	ovs_drop_reason_count 0x${ovs_drop_subsys}0004 # OVS_DROP_EXPLICIT_ACTION_ERROR
+	ovs_drop_reason_count OVS_DROP_EXPLICIT_WITH_ERROR
 	if [[ "$?" -ne "1" ]]; then
 		info "Did not detect expected explicit error drops: $?"
 		return 1

@@ -867,7 +858,7 @@ test_drop_reason() {
 
 	ovs_drop_record_and_run \
             "test_drop_reason" ip netns exec client nc -i 1 -zuv 172.31.110.20 7000
-	ovs_drop_reason_count 0x${ovs_drop_subsys}0003 # OVS_DROP_EXPLICIT_ACTION
+	ovs_drop_reason_count OVS_DROP_EXPLICIT
 	if [[ "$?" -ne "1" ]]; then
 		info "Did not detect expected explicit drops: $?"
 		return 1

No longer untested, that works.

Looks nicer than parsing obscure numbers indeed!

+1 !

Matthieu mentioned we'll need CONFIG_TRACEPOINTS in the selftest config
shard: tools/testing/selftests/net/openvswitch/config

Is that a new dependency or was it always there we just missed adding it
to the config before?  (it's included in the common net config, so that
is probably the reason why CI doesn't fail)

Yes, we missed it the first time around.

Best regards, Ilya Maximets.