Bug 1219864
| Summary: | grub2 cannot boot a compressed disk image via memdisk | ||||||
|---|---|---|---|---|---|---|---|
| Product: | Red Hat Enterprise Linux 7 | Reporter: | Daphne Shaw <dshaw> | ||||
| Component: | grub2 | Assignee: | Peter Jones <pjones> | ||||
| Status: | CLOSED ERRATA | QA Contact: | Release Test Team <release-test-team-automation> | ||||
| Severity: | unspecified | Docs Contact: | |||||
| Priority: | unspecified | ||||||
| Version: | 7.2 | CC: | dshaw, pholica | ||||
| Target Milestone: | rc | ||||||
| Target Release: | --- | ||||||
| Hardware: | Unspecified | ||||||
| OS: | Unspecified | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | grub-2.02-0.35.el7 | Doc Type: | Bug Fix | ||||
| Doc Text: | Story Points: | --- | |||||
| Clone Of: | Environment: | ||||||
| Last Closed: | 2016-11-04 03:58:18 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: | |||||||
| Attachments: |
|
||||||
I have worked with the grub2 people, and they acknowledge the bug. A fix was just committed:
commit a8c473288d3f0a5e17a903a5121dea1a695dda3b
Author: Andrei Borzenkov <arvidjaar>
Date: Thu May 7 20:24:24 2015 +0300
loader/linux: do not pad initrd with zeroes at the end
Syslinux memdisk is using initrd image and needs to know uncompressed
size in advance. For gzip uncompressed size is at the end of compressed
stream. Grub padded each input file to 4 bytes at the end, which means
syslinux got wrong size.
Linux initramfs loader apparently does not care about trailing alignment.
So change code to align beginning of each file instead which atomatically
gives us the correct size for single file.
Reported-By: David Shaw <dshaw>
Updating version. Problem still exists in grub2-2.02-0.33.el7_2.x86_64.rpm. Created attachment 1122174 [details]
memdisk-freedos-gz.png
Hello David,
is this the error you're seeing (see attachment)?
I've tried to start freedos floppy disk image without compression (which worked) and with gz compression which failed with attached screenshot.
Thanks
Correct, that's the error I'm getting. Just like with your test, an uncompressed image works fine, and a compressed image gives that error. There is some more discussion of the issue at http://lists.gnu.org/archive/html/grub-devel/2015-04/msg00095.html Great, thank you. Adding qa_ack then. 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, 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://rhn.redhat.com/errata/RHBA-2016-2336.html |
Description of problem: One solution to the problem of firmware (BIOS, etc) updater programs being only available for Windows or DOS is to use memdisk to boot a FreeDOS image containing the updater. Something like: menuentry "BIOS updater" { linux16 /memdisk iso initrd16 /updater.iso } This works fine, but if the image is compressed (memdisk supports both zip and gzip), there is a decompression error and the image cannot be booted. This worked correctly in legacy grub. Version-Release number of selected component (if applicable): grub2-2.02-0.16.el7 Steps to Reproduce: 1. Try and boot a compressed memdisk image. It will fail if the the image size is not a multiple of 4.