Bug 77582
| Summary: | SCSI emulation causes excessive load on bad CD media | ||
|---|---|---|---|
| Product: | [Retired] Red Hat Linux | Reporter: | Craig Lawson <craig.lawson> |
| Component: | kernel | Assignee: | Arjan van de Ven <arjanv> |
| Status: | CLOSED CURRENTRELEASE | QA Contact: | Mike McLean <mikem> |
| Severity: | high | Docs Contact: | |
| Priority: | medium | ||
| Version: | 7.3 | ||
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | i386 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2004-09-30 15:40:11 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: | |||
Thanks for the bug report. However, Red Hat no longer maintains this version of the product. Please upgrade to the latest version and open a new bug if the problem persists. The Fedora Legacy project (http://fedoralegacy.org/) maintains some older releases, and if you believe this bug is interesting to them, please report the problem in the bug tracker at: http://bugzilla.fedora.us/ |
Description of Problem: The SCSI emulation layer causes excessive system load when attempting to read from an ATAPI CD drive with bad media. Version-Release number of selected component (if applicable): Kernel 2.4.18.17.7.x i686 How Reproducible: 100% Steps to Reproduce: 1. Create a CD-R with media flaws. I used a CD full of JPEGs with a few scratches in the ink side of the CD. As it happened, the directory structure was intact, and only the file content was damaged. 2. Try to read the entire CD. Use "cp -vr" to locate the damaged files by name. Actual Results: When cp encounters the damaged files, it will stay on that file for a long time, and eventually report an I/O error. The system log "/var/log/messages" will report lots of messages like these: Nov 9 01:57:45 localhost kernel: SCSI bus is being reset for host 0 channel 0. Nov 9 01:57:45 localhost kernel: hdc: irq timeout: status=0x80 { Busy } Nov 9 01:57:45 localhost kernel: scsi : aborting command due to timeout : pid 6787, scsi0, channel 0, id 0, lun 0 Prevent/Allow Medium Removal 00 00 00 01 00 Nov 9 01:57:45 localhost kernel: SCSI host 0 abort (pid 6787) timed out - resetting some of these: Nov 9 01:57:45 localhost kernel: SCSI bus is being reset for host 0 channel 0. Nov 9 01:57:45 localhost kernel: scsi : aborting command due to timeout : pid 6786, scsi0, channel 0, id 0, lun 0 Read (10) 00 00 00 00 60 00 00 01 00 Nov 9 01:57:45 localhost kernel: SCSI host 0 abort (pid 6786) timed out - resetting and some of these: Nov 9 01:57:45 localhost kernel: SCSI bus is being reset for host 0 channel 0. Nov 9 01:57:45 localhost kernel: hdc: ATAPI reset complete Nov 9 01:57:52 localhost kernel: hdc: irq timeout: status=0x80 { Busy } Nov 9 01:57:52 localhost kernel: hdc: status timeout: status=0x80 { Busy } Nov 9 01:57:52 localhost kernel: hdc: drive not ready for command Nov 9 01:57:52 localhost kernel: scsi : aborting command due to timeout : pid 6787, scsi0, channel 0, id 0, lun 0 Prevent/Allow Medium Removal 00 00 00 01 00 Nov 9 01:57:52 localhost kernel: SCSI host 0 abort (pid 6787) timed out - resetting It takes a long time before the system gives up on a file and moves on to the next one. top reports the average system load rises to around 20. The system becomes extremely unresponsive. The system eventually completes the recursive copy, with bad files omitted, and the system load returns to normal. If there are enough flaws (on my CD, I had approximately 50 bad JPEG files, each about 600 Kb), after a couple hours of attempting to copy bad files, the system gets into a state where it cannot eject the media. Attempting to eject causes more SCSI bus resets, increased system load, unresponsiveness, and after several minutes the eject command fails. Expected Results: On encountering media read errors, I expected the system to retry a few times but not increase the system load to unreasonable levels. Eject should not fail. Additional Information: My system is: 933 Mhz P-III 512 Mb RAM hda: ATA disk hdc: PLEXTOR CD-R PX-W1610A, ATAPI CD/DVD-ROM drive hdd: LITEON DVD-ROM LTD163, ATAPI CD/DVD-ROM drive The problem occurs when reading bad CDs from either drive. Only one drive is in use at a time. When using xcdroast to read the same bad CD, it reports bad sectors. It takes a long time to read through the CD before eventually failing. However, the system load does not increase to an unreasonable level.