Description of problem: Live update the interface to delete the Qos setting will crash the libvirtd Version-Release number of selected component (if applicable): libvirt-7.0.0-2.module+el8.4.0+9520+ef609c5f.x86_64 How reproducible: 100% Steps to Reproduce: 1. Start a vm with interface set with Qos setting as below: [root@host]# virsh dumpxml test | grep /interface -B11 <interface type='network'> <mac address='52:54:00:58:ff:ab'/> <source network='default' portid='436047ca-70e6-4afa-927a-2707016c33ba' bridge='virbr0'/> <bandwidth> <inbound average='2000' peak='3000' burst='2048'/> <outbound average='256' peak='512' burst='512'/> </bandwidth> <target dev='vnet0'/> <model type='virtio'/> <alias name='net0'/> <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/> </interface> 2. dump the xml into a file as net.xml, and delete the Qos setting: [root@host]# cat net.xml <interface type='network'> <mac address='52:54:00:58:ff:ab'/> <source network='default' portid='3f9058c0-6f83-4dc7-adde-47d9bff8337f' bridge='virbr0'/> <target dev='vnet0'/> <model type='virtio'/> <alias name='net0'/> <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/> </interface> 3. use above xml to live update the vm xml to delete the Qos setting in the interface, it will crash the libvirt daemon: [root@host]# pidof libvirtd 1444010 [root@host]# virsh list --all Id Name State --------------------------------- 1 test running [root@host]# virsh update-device test net.xml error: Disconnected from qemu:///system due to end of file error: Failed to update device from net.xml error: End of file while reading data: Input/output error [root@host]# pidof libvirtd 1444119 Actual results: Live update the interface to delete the Qos setting will crash the libvirtd daemon Expected results: The libvirtd should not crash Additional info: No issue when clear the Qos setting by "# virsh domiftune test vnet0"
pls provide the backtrace of the coredump
attach the backtrace here： (gdb) c Continuing. [Detaching after fork from child process 63962] [Detaching after fork from child process 63963] Thread 5 "rpc-worker" received signal SIGSEGV, Segmentation fault. [Switching to Thread 0x7fc68b436700 (LWP 63843)] qemuDomainChangeNet (driver=driver@entry=0x7fc638138130, vm=vm@entry=0x55870316b6a0, dev=dev@entry=0x7fc680009750) at ../src/qemu/qemu_hotplug.c:3900 3900 if (!newb->in || newb->in->average == 0) (gdb) c Continuing. Couldn't get registers: No such process. Couldn't get registers: No such process. (gdb) [Thread 0x7fc623fff700 (LWP 63920) exited] [Thread 0x7fc64affd700 (LWP 63908) exited] [Thread 0x7fc64b7fe700 (LWP 63857) exited] [Thread 0x7fc65096e700 (LWP 63856) exited] [Thread 0x7fc64bfff700 (LWP 63854) exited] [Thread 0x7fc652af5700 (LWP 63853) exited] [Thread 0x7fc6532f6700 (LWP 63852) exited] [Thread 0x7fc660ac9700 (LWP 63851) exited] [Thread 0x7fc6612ca700 (LWP 63850) exited] [Thread 0x7fc690c31700 (LWP 63849) exited] [Thread 0x7fc691432700 (LWP 63848) exited] [Thread 0x7fc691c33700 (LWP 63847) exited] [Thread 0x7fc692434700 (LWP 63846) exited] [Thread 0x7fc692c35700 (LWP 63845) exited] [Thread 0x7fc693436700 (LWP 63844) exited] [Thread 0x7fc68b436700 (LWP 63843) exited] [Thread 0x7fc693c37700 (LWP 63842) exited] [Thread 0x7fc694438700 (LWP 63841) exited] [Thread 0x7fc694c39700 (LWP 63840) exited] Program terminated with signal SIGSEGV, Segmentation fault. The program no longer exists.
I'm setting HW All as I can reproduce this with libvirt-7.0.0-3.module+el8.4.0+9709+a99efd61.s390x qemu-kvm-5.2.0-4.module+el8.4.0+9676+589043b9.s390x For me this also hit the automated test - virtual_network.iface_network.qos_test.qos_option_bandwidth.by_update_device
Patch proposed upstream: https://listman.redhat.com/archives/libvir-list/2021-February/msg00851.html
Merged upstream as: a1229335f6 qemu_hotplug: Don't dereference NULL pointer @newb in qemuDomainChangeNet() v7.0.0-463-ga1229335f6
To POST: http://post-office.corp.redhat.com/archives/rhvirt-patches/2021-February/msg00348.html
Test on libvirt-7.0.0-4.module+el8.4.0+10093+e085f1eb.x86_64, the result is as expected, set the bug to be verified. Test scenarios includes: 1. Add Qos setting by update-device; 2. delete the Qos setting by update-device; 3. update Qos setting by update-device; 4. test with virsh cmd "domiftune" for above scenarios, all the result is as expected.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (virt:av bug fix and enhancement update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2021:2098