Bug 58867 - Adding mem=128M requires uppermem to be set as 127M
Summary: Adding mem=128M requires uppermem to be set as 127M
Alias: None
Product: Red Hat Linux
Classification: Retired
Component: grub (Show other bugs)
(Show other bugs)
Version: 7.2
Hardware: i386 Linux
Target Milestone: ---
Assignee: Jeremy Katz
QA Contact:
Depends On:
TreeView+ depends on / blocked
Reported: 2002-01-26 03:00 UTC by Yusuf Goolamabbas
Modified: 2008-05-01 15:38 UTC (History)
0 users

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2002-01-26 03:00:32 UTC
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)

Description Yusuf Goolamabbas 2002-01-26 03:00:27 UTC
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.7+) Gecko/20020123

Description of problem:
If one wants to boot a system with mem=128M and an initrd exists
it requires that uppermem be set as
uppermem 130048
instead of 
uppermem 130172

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1. Modify /etc/grub.conf to add mem=128M to the kernel line
2. Add an uppermem 130172 before the kernel command line
3. Reboot

Actual Results:  Boot fails with grub complaining that it can't find the root device
Taking out the mem=128M and uppermem command makes it work
Another way is to modify uppermem to be
uppermem 130048

This is mentioned in this URL though I can't figure out why

I don't know if this is a grub feature/bug or maybe some grub/kernel interaction

Is there a formulae to determine the correct value of uppermem depending on the
value of mem="XX"M. If so, could this be documented somewhere

Additional info:

Comment 1 Jeremy Katz 2002-01-26 03:28:13 UTC
Actually as of the package I just built (grub-0.91-2), you shouldn't have to
specify uppermem anymore as it will parse the kernel command line and figure out
where the initrd is supposed to be loaded.

Comment 2 Yusuf Goolamabbas 2002-01-26 03:32:43 UTC
Is this being slated for an errata release ?

Note You need to log in before you can comment on or make changes to this bug.