Bug 678562
| Summary: | writing to a virtio serial port while no one is listening on the host side hangs the guest [rhel-6.0.z] | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | RHEL Program Management <pm-rhel> |
| Component: | kernel | Assignee: | Frantisek Hrbata <fhrbata> |
| Status: | CLOSED ERRATA | QA Contact: | Red Hat Kernel QE team <kernel-qe> |
| Severity: | medium | Docs Contact: | |
| Priority: | low | ||
| Version: | 6.0 | CC: | amit.shah, dhoward, hdegoede, juzhang, mjenner, plyons, pm-eus, virt-maint |
| Target Milestone: | rc | Keywords: | ZStream |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | kernel-2.6.32-71.19.1.el6 | Doc Type: | Bug Fix |
| Doc Text: |
If a host was slow in reading data or did not read data at all, blocking write() calls not only blocked the program that called the write() call but also the entire guest. This was caused by the write() calls waiting until an acknowledgment that the data consumed was received from the host. With this update, write() calls no longer wait for such acknowledgment: control is immediately returned to the user space application. This ensures that even if the host is busy processing other data or is not consuming data at all, the guest is not blocked.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2011-04-08 02:59:49 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: | 643751 | ||
| Bug Blocks: | |||
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Description
RHEL Program Management
2011-02-18 12:41:06 UTC
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-2011-0421.html
Technical note added. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.
New Contents:
If a host was slow in reading data or did not read data at all, blocking write() calls not only blocked the program that called the write() call but also the entire guest. This was caused by the write() calls waiting until an acknowledgment that the data consumed was received from the host. With this update, write() calls no longer wait for such acknowledgment: control is immediately returned to the user space application. This ensures that even if the host is busy processing other data or is not consuming data at all, the guest is not blocked.
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