https://bugzilla.redhat.com/show_bug.cgi?id=1177723 If tc cmd failed (maybe value too large) when we use virDomainSetInterfaceParameters , the old rules will be clean. Restore the old rules if tc failed. Signed-off-by: Luyao Huang <lhuang(a)redhat.com&gt; --- v1 make a big mistake that i used a old libvirt src/qemu/qemu_driver.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 73a825d..650e0dd 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -10494,8 +10494,12 @@ qemuDomainSetInterfaceParameters(virDomainPtr dom, sizeof(*newBandwidth->out)); } - if (virNetDevBandwidthSet(net->ifname, newBandwidth, false) < 0) + if (virNetDevBandwidthSet(net->ifname, newBandwidth, false) < 0) { + ignore_value(virNetDevBandwidthSet(net->ifname, + net->bandwidth, + false)); goto endjob; + } virNetDevBandwidthFree(net->bandwidth); if (newBandwidth->in || newBandwidth->out) {