New ticket EFFECT: We occasionally trigger what seems to be a known kernel bug in the reference count handling of VLAN interfaces. A PMD is generated, see enclosed file, which shows this message in the syslog/dmesg log: <0>[ 7921.630591] unregister_netdevice: waiting for eth10.170 to become free. Usage count = 2 When this bug is triggered our dpsd process hangs which causes the kernel to panic. MEASURES: This patch, submitted to Linux 3.10.72, will probably resolve the issue: https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/?h=linux-3.10.y&id=140b057ced8f43b93c4d934eb94661782155f683