Bug 2009310
| Summary: | Qemu coredump when backup with x-perf | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 9 | Reporter: | aihua liang <aliang> |
| Component: | qemu-kvm | Assignee: | Stefano Garzarella <sgarzare> |
| qemu-kvm sub component: | Incremental Live Backup | QA Contact: | aihua liang <aliang> |
| Status: | CLOSED ERRATA | Docs Contact: | |
| Severity: | high | ||
| Priority: | high | CC: | coli, jinzhao, juzhang, kkiwi, mrezanin, ngu, qzhang, sgarzare, virt-maint |
| Version: | 9.0 | Keywords: | Triaged |
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | qemu-kvm-6.2.0-1.el9 | Doc Type: | If docs needed, set a value |
| Doc Text: | Story Points: | --- | |
| Clone Of: | 2009236 | Environment: | |
| Last Closed: | 2022-05-17 12:24:29 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: | 2009236 | ||
| Bug Blocks: | |||
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Description
aihua liang
2021-09-30 10:42:15 UTC
Test Env in RHEL9: kernel version:5.14.0-3.el9.x86_64 qemu-kvm version:qemu-kvm-6.1.0-2.el9 (In reply to aihua liang from comment #0) The problem is an integer overflow related to the `max-workers` parameter: > 3.Do backup with x-perf option > {"execute": "blockdev-backup", "arguments": {"device": > "drive_image1","job-id": "j1", "sync": "full", "target": > "sn1","x-perf":{"use-copy-range":true,"max-workers":4294967296,"max-chunk": > 4294967296}}} QAPI generates a structure and store `max-workers` value in an `int64_t` variable, while in the code (block/aio_task.c - max_busy_tasks) an `int` is used. So the maximum right value should be INT_MAX (2147483647). I'll send a patch adding a check for that with an error message. @aliang Can you check that everything is okay by using `max-workers` values up to 2147483647? I did a quick check and it looks okay in my environment if `max-workers` is between 1 and 2147483647. Fixes posted upstream: https://lists.nongnu.org/archive/html/qemu-devel/2021-10/msg00934.html Test backup with following max-workers value, all works ok.
"max-workers":2147483647,"max-chunk":2147483647
"max-workers":65536,"max-chunk":65536
"max-workers":1,"max-chunk":1048576
"max-workers":1,"max-chunk":0
So it works ok between 1 and 2147483647.
Fix merged upstream: https://gitlab.com/qemu-project/qemu/-/commit/8fc898ce0b3e7fea8c7c2a8d8977f2a9b77ecebf Test with qemu-kvm-6.2.0-1.el9, don't hit this issue any more.
1.Start guest with qemu cmds:
/usr/libexec/qemu-kvm \
-name 'avocado-vt-vm1' \
-sandbox on \
-machine q35,memory-backend=mem-machine_mem \
-device pcie-root-port,id=pcie-root-port-0,multifunction=on,bus=pcie.0,addr=0x1,chassis=1 \
-device pcie-pci-bridge,id=pcie-pci-bridge-0,addr=0x0,bus=pcie-root-port-0 \
-nodefaults \
-device VGA,bus=pcie.0,addr=0x2 \
-m 30720 \
-object memory-backend-ram,size=30720M,id=mem-machine_mem \
-smp 10,maxcpus=10,cores=5,threads=1,dies=1,sockets=2 \
-cpu 'Cascadelake-Server-noTSX',+kvm_pv_unhalt \
-chardev socket,server=on,id=qmp_id_qmpmonitor1,wait=off,path=/tmp/monitor-qmpmonitor1-20210927-235344-uQJJ6aFc \
-mon chardev=qmp_id_qmpmonitor1,mode=control \
-chardev socket,server=on,id=qmp_id_catch_monitor,wait=off,path=/tmp/monitor-catch_monitor-20210927-235344-uQJJ6aFc \
-mon chardev=qmp_id_catch_monitor,mode=control \
-device pvpanic,ioport=0x505,id=idmerT3z \
-chardev socket,server=on,id=chardev_serial0,wait=off,path=/tmp/serial-serial0-20210927-235344-uQJJ6aFc \
-device isa-serial,id=serial0,chardev=chardev_serial0 \
-chardev socket,id=seabioslog_id_20210927-235344-uQJJ6aFc,path=/tmp/seabios-20210927-235344-uQJJ6aFc,server=on,wait=off \
-device isa-debugcon,chardev=seabioslog_id_20210927-235344-uQJJ6aFc,iobase=0x402 \
-device pcie-root-port,id=pcie-root-port-1,port=0x1,addr=0x1.0x1,bus=pcie.0,chassis=2 \
-device qemu-xhci,id=usb1,bus=pcie-root-port-1,addr=0x0 \
-device usb-tablet,id=usb-tablet1,bus=usb1.0,port=1 \
-device pcie-root-port,id=pcie-root-port-2,port=0x2,addr=0x1.0x2,bus=pcie.0,chassis=3 \
-device virtio-scsi-pci,id=virtio_scsi_pci0,bus=pcie-root-port-2,addr=0x0 \
-blockdev node-name=file_image1,driver=file,auto-read-only=on,discard=unmap,aio=threads,filename=/home/kvm_autotest_root/images/rhel900-64-virtio-scsi.qcow2,cache.direct=on,cache.no-flush=off \
-blockdev node-name=drive_image1,driver=qcow2,read-only=off,cache.direct=on,cache.no-flush=off,file=file_image1 \
-device scsi-hd,id=image1,drive=drive_image1,write-cache=on \
-device pcie-root-port,id=pcie-root-port-3,port=0x3,addr=0x1.0x3,bus=pcie.0,chassis=4 \
-device virtio-net-pci,mac=9a:c0:90:a7:2f:40,id=idjZ1FPm,netdev=id4rOUG1,bus=pcie-root-port-3,addr=0x0 \
-netdev tap,id=id4rOUG1,vhost=on \
-vnc :0 \
-rtc base=utc,clock=host,driftfix=slew \
-boot menu=off,order=cdn,once=c,strict=off \
-enable-kvm \
-device pcie-root-port,id=pcie_extra_root_port_0,multifunction=on,bus=pcie.0,addr=0x3,chassis=5 \
-monitor stdio \
-qmp tcp:0:3000,server=on,wait=off \
2. Create backup target node
{'execute':'blockdev-create','arguments':{'options': {'driver':'file','filename':'/root/sn1','size':21474836480},'job-id':'job1'}}
{'execute':'blockdev-add','arguments':{'driver':'file','node-name':'drive_sn1','filename':'/root/sn1'}}
{'execute':'blockdev-create','arguments':{'options': {'driver': 'qcow2','file':'drive_sn1','size':21474836480},'job-id':'job2'}}
{'execute':'blockdev-add','arguments':{'driver':'qcow2','node-name':'sn$i','file':'drive_sn$i'}}
{'execute':'job-dismiss','arguments':{'id':'job1'}}
{'execute':'job-dismiss','arguments':{'id':'job2'}}
3.Do backup with x-perf option
{"execute": "blockdev-backup", "arguments": {"device": "drive_image1","job-id": "j1", "sync": "full", "target": "sn1","x-perf":{"use-copy-range":true,"max-workers":4294967296,"max-chunk":4294967296}}}
In step3, backup can't start with error info:
{"error": {"class": "GenericError", "desc": "max-workers must be between 1 and 2147483647"}}
QE bot(pre verify): Set 'Verified:Tested,SanityOnly' as gating/tier1 test pass. 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 (new packages: qemu-kvm), 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-2022:2307 |