Re: [libvirt] [PATCH 5/9] qemuDomainSetInterfaceParameters: Use new functions to update bandwidth

As sketched in previous commits, imagine the following scenario: virsh # domiftune gentoo vnet0 inbound.average: 100 inbound.peak : 0 inbound.burst : 0 outbound.average: 100 outbound.peak : 0 outbound.burst : 0 virsh # domiftune gentoo vnet0 --inbound 0 virsh # shutdown gentoo Domain gentoo is being shutdown virsh # list --all error: Failed to list domains error: Cannot recv data: Connection reset by peer Program received signal SIGSEGV, Segmentation fault. 0x00007fffe80ea221 in networkUnplugBandwidth (net=0x7fff9400c1a0, iface=0x7fff940ea3e0) at network/bridge_driver.c:4881 4881 net->floor_sum -= ifaceBand->in->floor; This is rather unfortunate. We should not SIGSEGV here. The problem is, that while in the second step the inbound QoS was cleared out, the network part of it was not updated (moreover, we don't report that vnet0 had inbound.floor set). Internal structure therefore still had some fragments left (e.g. class_id). So when qemuProcessStop() started to clean up the environment it got to networkUnplugBandwidth(). Here, class_id is set therefore function assumes that there is an inbound QoS. This actually is a fair assumption to make, there's no need for a special QoS box in network's QoS when there's no QoS to set. Anyway, the problem is not the networkUnplugBandwidth() rather than qemuDomainSetInterfaceParameters() which completely forgot about QoS being disperse (some parts are set directly on interface itself, some on bridge the interface is plugged into). Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/qemu/qemu_driver.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index b9278f8..171b58f 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -100,6 +100,7 @@ #include "vircgroup.h" #include "virnuma.h" #include "dirname.h" +#include "network/bridge_driver.h" #define VIR_FROM_THIS VIR_FROM_QEMU @@ -11221,7 +11222,11 @@ qemuDomainSetInterfaceParameters(virDomainPtr dom, sizeof(*newBandwidth->out)); } - if (virNetDevBandwidthSet(net->ifname, newBandwidth, false) < 0) { + if (!networkBandwidthChangeAllowed(net, newBandwidth)) + goto endjob; + + if (virNetDevBandwidthSet(net->ifname, newBandwidth, false) < 0 || + networkBandwidthUpdate(net, newBandwidth) < 0) {

ignore_value(virNetDevBandwidthSet(net->ifname, net->bandwidth, false));