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Description of problem: with the same guest , and nothing modified for the guest would got the following error output occasionally # virsh start RHEL5.6-i386 error: Failed to start domain RHEL5.6-i386 error: internal error Out of space while reading console log output: 11:13:54.230: 4311: info : libvirt version: 0.8.7, package: 8.el6 (Red Hat, Inc. <http://bugzilla.redhat.com/bugzilla>, 2011-02-24-17:53:33, x86-006.build.bos.redhat.com) 11:13:54.230: 4311: debug : virCgroupNew:555 : New group /libvirt/qemu/RHEL5.6-i386 11:13:54.230: 4311: debug : virCgroupDetect:245 : Detected mount/mapping 0:cpu at /cgroup/cpu in 11:13:54.230: 4311: debug : virCgroupDetect:245 : Detected mount/mapping 1:cpuacct at /cgroup/cpuacct in 11:13:54.230: 4311: debug : virCgroupDetect:245 : Detected mount/mapping 2:cpuset at /cgroup/cpuset in 11:13:54.230: 4311: debug : virCgroupDetect:245 : Detected mount/mapping 3:memory at /cgroup/memory in 11:13:54.230: 4311: debug : virCgroupDetect:245 : Detected mount/mapping 4:devices at /cgroup/devices in 11:13:54.230: 4311: debug : virCgroupDetect:245 : Detected mount/mapping 5:freezer at /cgroup/freezer in 11:13:54.230: 4311: debug : virCgroupDetect:245 : Detected mount/mapping 6:blkio at /cgroup/blki Version-Release number of selected component (if applicable): libvirt-0.8.7-8.el6.x86_64 Steps to Reproduce: 1. virsh start guest 2. 3. Actual results: Expected results: no such error output prevent from starting the guest Additional info:
The problem is a stack-allocated buffer in qemudWaitForMonitor: char buf[4096] = ""; /* Plenty of space to get startup greeting */ Apparently, it's much less than plenty, it's even not enough since it also needs to accommodate all the debug messages printed by libvirt when it prepares for starting up qemu binary.
It was never expected to have to store debug messages. In addition those debug messages aren't really something we want to pass onto the user in the error message. If QEMU fails, we need to figure out how to skip over the libvirt debug messages & just provide the QEMU error message. If we manage that, then 4k should still be sufficient for the QEMU error message.
Created attachment 483123 [details] /var/log/libvirt/qemu/guest.log
Patch sent for review: http://post-office.corp.redhat.com/archives/rhvirt-patches/2011-April/msg00001.html
retested with libvirt-0.8.7-16.el6.x86_64 qemu-kvm-0.12.1.2-2.153.el6.x86_64 kernel-2.6.32-128.el6.x86_64 1. virsh start guest for about 30 times , didn't meet "Out of space" error . So set bug status to VERIFIED
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHBA-2011-0596.html