Bug 1582042
| Summary: | Segfault on 'blockdev-mirror' with same node as source and target | ||||||
|---|---|---|---|---|---|---|---|
| Product: | Red Hat Enterprise Linux 7 | Reporter: | Gu Nini <ngu> | ||||
| Component: | qemu-kvm-rhev | Assignee: | Kevin Wolf <kwolf> | ||||
| Status: | CLOSED ERRATA | QA Contact: | Gu Nini <ngu> | ||||
| Severity: | high | Docs Contact: | |||||
| Priority: | high | ||||||
| Version: | 7.6 | CC: | areis, chayang, jsnow, juzhang, knoel, kwolf, lmiksik, michen, mrezanin, mtessun, qzhang, virt-maint, xianwang | ||||
| Target Milestone: | rc | ||||||
| Target Release: | --- | ||||||
| Hardware: | Unspecified | ||||||
| OS: | Unspecified | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | qemu-kvm-rhev-2.12.0-14.el7 | Doc Type: | If docs needed, set a value | ||||
| Doc Text: | Story Points: | --- | |||||
| Clone Of: | |||||||
| : | 1637963 (view as bug list) | Environment: | |||||
| Last Closed: | 2018-11-01 11:09:52 UTC | Type: | Bug | ||||
| Regression: | --- | Mount Type: | --- | ||||
| Documentation: | --- | CRM: | |||||
| Verified Versions: | Category: | --- | |||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||
| Embargoed: | |||||||
| Bug Depends On: | |||||||
| Bug Blocks: | 1637963 | ||||||
| Attachments: |
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Created attachment 1440937 [details]
The gdb info on 05242018
The scenario can be considerably simplified. The problem is that at the end both 'drive_image2' and 'drive2' point to the same node and you're trying to mirror /home/hd1.qcow2 to itself.
The same case can be reproduced like this :
$ qemu-img create -f qcow2 /tmp/test.qcow2 64M
$ qemu-system-x86_64 -drive file=/tmp/overlay.qcow2,id=disk -qmp stdio
{"execute":"qmp_capabilities"}
{"execute":"blockdev-mirror","arguments":{"device":"disk","target":"disk","sync":"full"}}
Fix included in qemu-kvm-rhev-2.12.0-14.el7 Verify the bug on qemu-kvm-rhev-2.12.0-14.el7:
# nc -U /var/tmp/avocado1
{"QMP": {"version": {"qemu": {"micro": 0, "minor": 12, "major": 2}, "package": "qemu-kvm-rhev-2.12.0-14.el7"}, "capabilities": []}}
{"execute":"qmp_capabilities"}
{"return": {}}
{"execute":"blockdev-add","arguments":{"driver":"qcow2","node-name":"disk33","file":{"driver":"file","filename":"/home/hd33.qcow2"}}}
{"return": {}}
{"timestamp": {"seconds": 1536716756, "microseconds": 705448}, "event": "VSERPORT_CHANGE", "data": {"open": true, "id": "qemu-ga0"}}
{"timestamp": {"seconds": 1536716760, "microseconds": 565778}, "event": "NIC_RX_FILTER_CHANGED", "data": {"name": "id8e5D72", "path": "/machine/peripheral/id8e5D72/virtio-backend"}}
{ "execute": "blockdev-snapshot", "arguments": { "node":"drive_image3","overlay":"disk33"}}
{"return": {}}
{ "execute": "blockdev-mirror","arguments":{"device":"drive_image3","target":"disk33","sync":"full"}}
{"error": {"class": "GenericError", "desc": "Can't mirror node into itself"}}
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, 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-2018:3443 |
Description of problem: Boot up a guest with a data disk, add an existed disk image with 'blockdev-add', do 'blockdev-snapshot' to the data disk, then do 'blockdev-mirror' to the same source/target disk, guest 'Segmentation fault (core dumped)'. Version-Release number of selected component (if applicable): Host kernel: 3.10.0-888.el7.x86_64 Qemu-kvm-rhev: qemu-kvm-rhev-2.12.0-2.el7.x86_64 Guest kernel: 3.10.0-889.el7.x86_64 How reproducible: 100% Steps to Reproduce: 1. Boot up a guest with a data disk 'drive_image2': -drive id=drive_image2,if=none,snapshot=off,aio=threads,cache=none,format=qcow2,file=/home/hd1 \ -device scsi-hd,id=image2,drive=drive_image2 \ 2. Create a disk image with the same size of above disk: # qemu-img create -f qcow2 hd1.qcow2 2G 3. Add the created disk as 'drive2' with 'blockdev-add': # nc -U /var/tmp/avocado1 {"QMP": {"version": {"qemu": {"micro": 0, "minor": 12, "major": 2}, "package": "qemu-kvm-rhev-2.12.0-2.el7"}, "capabilities": []}} {"execute":"qmp_capabilities"} {"return": {}} {"execute":"blockdev-add","arguments":{"driver":"qcow2","node-name":"drive2","file":{"driver":"file","filename":"/home/hd1.qcow2"}} } {"return": {}} 4. Create snapshot for above 'drive_image2' on the new disk 'drive2': { "execute": "blockdev-snapshot", "arguments": { "node":"drive_image2","overlay":"drive2"}} {"return": {}} 5. To do error handle test, continue to create a mirror for the 'drive_image2' on the same target disk 'drive2': { "execute": "blockdev-mirror","arguments":{"device":"drive_image2","target":"drive2","sync":"full"}} Ncat: Connection reset by peer. Actual results: Segmentation fault (core dumped) to the guest. Expected results: Error prompt as follows in qmp: {"error": {"class": "GenericError", "desc": "The snapshot is already in use"}} or {"error": {"class": "GenericError", "desc": "Failed to get \"write\" lock"}} Additional info: 1. If create mirror first then create a snapshot on the same target, there is following error prompt without other issues: ...... { "execute": "block-job-complete","arguments":{"device":"drive_image2"}} {"return": {}} {"timestamp": {"seconds": 1527132274, "microseconds": 118837}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "drive_image2", "len": 0, "offset": 0, "speed": 0, "type": "mirror"}} { "execute": "blockdev-snapshot", "arguments": { "node":"drive_image2","overlay":"drive2"}} {"error": {"class": "GenericError", "desc": "The snapshot is already in use"}} 2. If do similar test using 'blockdev-snapshot-sync' and 'drive-mirror' instead, the error prompt is as follows without any other issue: { "execute": "blockdev-snapshot-sync", "arguments": { "device": "drive_image2","snapshot-file":"sn1","format":"qcow2","mode":"absolute-paths"}} {"return": {}} { "execute": "drive-mirror", "arguments": { "device": "drive_image2","target": "sn1", "format": "qcow2", "mode": "absolute-paths", "sync": "full"}} {"error": {"class": "GenericError", "desc": "Failed to get \"write\" lock"}}