bugGNU GRUB - Bugs: bug #18471, [PATCH] Grub overwrites reserved...


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bug #18471: [PATCH] Grub overwrites reserved memory region when reading initrd file

Submitted by:  Beverly Brown <bbrown_gnu>
Submitted on:  Wed 06 Dec 2006 04:14:55 PM UTC  
Category:  Booting Severity:  Major
Priority:  5 - Normal Item Group:  Software Error
Status:  None Privacy:  Public
Assigned to:  None Originator Name:  Beverly Brown
Open/Closed:  Closed Release:  0.93
Release:  None Reproducibility:  None
Planned Release:  None

Sat 15 Dec 2007 09:34:21 PM UTC, comment #2: 

We've moved to GRUB 2 as a development platform. Please can you check if this bug still applies there, and if it does, reopen it?


Robert Millan <robertmh>
Project Administrator
Mon 26 Mar 2007 09:21:25 PM UTC, comment #1: 

It was brought to my attention that the nocopy patch may not work on some systems. This patch supercedes that one. It loads the initrd in 1MB increments. This way it will avoid trashing BIOS reserved memory and also will not pose a problem for systems with large memory where the operation reading directly from disk may not be able to access the upper memory regions.

Beverly Brown <bbrown_gnu>
Wed 06 Dec 2006 04:14:55 PM UTC, original submission:  

When grub reads in an initrd that is larger than ~13MB, it overwrites a memory region that is reserved by the system BIOS in some systems.

The original load_initrd function in grub was reading in the initrd file without regard to where memory holes in the memory map may be. Then it determined where it needed to be in order to pass it on to Linux and copied it there.

The overwrite was happening during the initial read, so I removed that step. The function now determines where the initrd code needs to be and puts it there without the initial read. It no longer overwrites the memory region reserved by the BIOS.

The patch is attached.

Beverly Brown <bbrown_gnu>


Attached Files
file #12304:  grub-0.93-initrd-smallcopy.patch added by bbrown_gnu (2KiB - application/octet-stream - It was brought to my attention that the nocopy patch may not work on some systems. This patch supercedes that one. It loads the initrd in 1MB increments.)


Depends on the following items: None found

Items that depend on this one: None found


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    Follow 4 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2007-12-15 robertmh Open/ClosedOpen => Closed
    2007-03-26 bbrown_gnu Attached File- => Added grub-0.93-initrd-smallcopy.patch, #12304
    2006-12-06 bbrown_gnu Attached File- => Added grub-0.93-initrd_nocopy.patch, #11462
        Carbon-Copy- => Added bbrown_gnu

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