Bug 628634
| Summary: | vhost_net: untested error handling in vhost_net_start | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | Jes Sorensen <Jes.Sorensen> |
| Component: | qemu-kvm | Assignee: | jason wang <jasowang> |
| Status: | CLOSED ERRATA | QA Contact: | Virtualization Bugs <virt-bugs> |
| Severity: | medium | Docs Contact: | |
| Priority: | low | ||
| Version: | 6.1 | CC: | akong, gcosta, lihuang, mkenneth, tburke, virt-maint |
| Target Milestone: | beta | ||
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | qemu-kvm-0.12.1.2-2.126.el6 | Doc Type: | Bug Fix |
| Doc Text: |
Cause: bug in the error handling code of vhost, check whether an unsigned value is greater than zero would make the result always true.
Consequence: qemu-kvm would hang when it met errors when start a vhost_net backend.
Fix: Fix the error handling code.
Result: qemu-kvm would never hang when it fails to start vhost_net backend.
|
Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2011-05-19 11:33:09 UTC | Type: | --- |
| 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: | 580954 | ||
Taking as I have a fix. Ok back to Michael as he has a different fix. How is it going upstream? Also, how important it is to have it in 6.1? The fix have already in upstream, just need to be backported in 6.1
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Cause: bug in the error handling code of vhost, check whether an unsigned value is greater than zero would make the result always true.
Consequence: qemu-kvm would hang when it met errors when start a vhost_net backend.
Fix: Fix the error handling code.
Result: qemu-kvm would never hang when it fails to start vhost_net backend.
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/RHSA-2011-0534.html 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/RHSA-2011-0534.html |
Description of problem: hw/vhost_net.c:vhost_net_start() seems to have untested error handling. The code looks like this: int vhost_net_start(struct vhost_net *net, VirtIODevice *dev) { struct vhost_vring_file file = { }; ... for (file.index = 0; file.index < net->dev.nvqs; ++file.index) { r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file); if (r < 0) { r = -errno; goto fail; } } return 0; fail: file.fd = -1; while (--file.index >= 0) { int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file); assert(r >= 0); } As file.index is an unsigned integer, the while() loop will always be true, so in case of error we will exit on an assert or loop forever. This is present in both RHEL6 and upstream QEMU. It is not obvious to me what the code was intended to do here, so please have a look. Version-Release number of selected component (if applicable): How reproducible: Steps to Reproduce: 1. 2. 3. Actual results: Expected results: Additional info: