Re: [PATCH net 2/2] selftests: forwarding: bridge: add a state bypass with disabled VLAN filtering test

On 11/4/25 19:15, Petr Machata wrote:

Nikolay Aleksandrov [off-list ref] writes:

quoted

Add a test which checks that port state bypass cannot happen if we have
VLAN filtering disabled and MST enabled. Such bypass could lead to race
condition when deleting a port because learning may happen after its
state has been toggled to disabled while it's being deleted, leading to
a use after free.

Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
---
 .../net/forwarding/bridge_vlan_unaware.sh     | 35 ++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/forwarding/bridge_vlan_unaware.sh b/tools/testing/selftests/net/forwarding/bridge_vlan_unaware.sh
index 2b5700b61ffa..20769793310e 100755
--- a/tools/testing/selftests/net/forwarding/bridge_vlan_unaware.sh
+++ b/tools/testing/selftests/net/forwarding/bridge_vlan_unaware.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 # SPDX-License-Identifier: GPL-2.0
 
-ALL_TESTS="ping_ipv4 ping_ipv6 learning flooding pvid_change"
+ALL_TESTS="ping_ipv4 ping_ipv6 learning flooding pvid_change mst_state_no_bypass"

I think you'll need to adjust this test for v2, can you please change
the above line to the following while at it?

ack

ALL_TESTS="
	ping_ipv4
	ping_ipv6
	learning
	flooding
	pvid_change
	mst_state_no_bypass
"

quoted

 NUM_NETIFS=4
 source lib.sh
 

@@ -114,6 +114,39 @@ pvid_change()
 	ping_ipv6 " with bridge port $swp1 PVID deleted"
 }
 
+mst_state_no_bypass()
+{
+	local mac=de:ad:be:ef:13:37
+
+	# Test that port state isn't bypassed when MST is enabled and VLAN
+	# filtering is disabled
+	RET=0
+
+	# MST can be enabled only when there are no VLANs
+	bridge vlan del vid 1 dev $swp1
+	bridge vlan del vid 1 dev $swp2

Pretty sure these naked references will explode in the CI's shellcheck.
I expect they'll have to be quoted as "$swp1".

Oh haven't written selftests in awhile, I've missed the shellcheck stuff. :)

quoted

+	bridge vlan del vid 1 dev br0 self
+
+	ip link set br0 type bridge mst_enabled 1
+	check_err $? "Could not enable MST"
+
+	bridge link set dev $swp1 state disabled

Here as well. And more cases are below.

I've got this in my bash history. Might come in handy.

    cat files | while read file; do git show net-next/main:$file > file; shellcheck file > sc-old; git show HEAD:$file > file; shellcheck file > sc-new; echo $file; diff -u sc-old sc-new; done | less

 
Thanks for the hint. I'll add this to my patch review process as well.

Cheers,
 Nik

quoted

+	check_err $? "Could not set port state"
+
+	$MZ $h1 -c 1 -p 64 -a $mac -t ip -q
+
+	bridge fdb show brport $swp1 | grep -q de:ad:be:ef:13:37
+	check_fail $? "FDB entry found when it shouldn't be"
+
+	log_test "VLAN filtering disabled and MST enabled port state no bypass"
+
+	ip link set br0 type bridge mst_enabled 0
+	bridge link set dev $swp1 state forwarding
+	bridge vlan add vid 1 dev $swp1 pvid untagged
+	bridge vlan add vid 1 dev $swp2 pvid untagged
+	bridge vlan add vid 1 dev br0 self
+}
+
 trap cleanup EXIT
 
 setup_prepare