GNU bug report logs - #33389
parted not recognizing partitions in "non-standard" MBRs with valid partition tables

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 33389 in the body.
You can then email your comments to 33389 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Marc Stenson <marcstenson <at> gmail.com>
To: bug-parted <at> gnu.org
Subject: parted not recognizing partitions in "non-standard" MBRs with valid
 partition tables
Date: Thu, 15 Nov 2018 00:27:02 +0200

Hello,

While parted 2.3 had no issues with whatever was in the first 446 bytes 
of the MBR and only looked at the partition table, newer versions such 
as 3.2 seem to be thrown by unusual boot code (e.g. Grub4DOS) and either 
show the entire disk as unallocated space or as one big volume/partition 
with the file system of the first volume. This is despite the partition 
table being fully compliant and happily read by fdisk and sfdisk.

This may be a "feature" rather than a bug.   Please pardon my ignorance, 
perhaps newer partition table schemes require the first 446 bits to be 
parsed.  However it could save someone many hours of frustration if this 
was noted prominently in the documentation.

In my case It was fixed with a simple:
  dd if=/usr/lib/syslinux/mbr/mbr.bin of=/dev/sdb bs=446 count=1
after taking the requisite backups and a deep breath.

Thanks and regards,
Marc

Message #8 received at submit <at> debbugs.gnu.org (full text, mbox):

From: "Brian C. Lane" <bcl <at> redhat.com>
To: bug-parted <at> gnu.org
Subject: Re: bug#33389: parted not recognizing partitions in "non-standard"
 MBRs with valid partition tables
Date: Fri, 16 Nov 2018 10:27:19 -0800

On Thu, Nov 15, 2018 at 12:27:02AM +0200, Marc Stenson wrote:
> Hello,
> 
> While parted 2.3 had no issues with whatever was in the first 446 bytes of
> the MBR and only looked at the partition table, newer versions such as 3.2
> seem to be thrown by unusual boot code (e.g. Grub4DOS) and either show the
> entire disk as unallocated space or as one big volume/partition with the
> file system of the first volume. This is despite the partition table being
> fully compliant and happily read by fdisk and sfdisk.
> 
> This may be a "feature" rather than a bug.   Please pardon my ignorance,
> perhaps newer partition table schemes require the first 446 bits to be
> parsed.  However it could save someone many hours of frustration if this was
> noted prominently in the documentation.
> 
> In my case It was fixed with a simple:
>   dd if=/usr/lib/syslinux/mbr/mbr.bin of=/dev/sdb bs=446 count=1
> after taking the requisite backups and a deep breath.

Can you explain steps to reproduce this, or post the first 1M of your
disk someplace?

-- 
Brian C. Lane (PST8PDT)

Message #13 received at 33389-done <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Philipp <p.stephani2 <at> gmail.com>
Cc: 33389-done <at> debbugs.gnu.org
Subject: 26.1.90; Emacs occasionally fails to receive asynchronous subprocess
 output in batch mode
Date: Thu, 27 Dec 2018 12:58:30 -0800

[Message part 1 (text/plain, inline)]

> I don't think the manual states that output can
> arrive after the process has finished, but if that's the case, then it
> should do so.

Good point, and I installed the attached patch into emacs-26 to try to do that.

As this bug report seems to stem from a misunderstanding of 
accept-process-output (quite understandable, as its functionality is obscure) 
I'm taking the liberty of closing the report. If I'm wrong please feel free to 
reopen it.

[0001-Improve-accept-process-process-doc.patch (text/x-patch, attachment)]

Message #18 received at 33389 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: 33389 <at> debbugs.gnu.org
Cc: "Brian C. Lane" <bcl <at> redhat.com>, Philipp <p.stephani2 <at> gmail.com>,
 Marc Stenson <marcstenson <at> gmail.com>
Subject: Re: parted not recognizing partitions in "non-standard" MBRs with
 valid partition tables
Date: Thu, 27 Dec 2018 13:04:10 -0800

Sorry about closing Bug#33389 (for parted) by accident. I reopened it just now.

I meant to close Bug#33839 (for Emacs) and plan to do that shortly.

Message #23 received at 33389-done <at> debbugs.gnu.org (full text, mbox):

From: Phillip Susi <phill <at> thesusis.net>
To: Marc Stenson <marcstenson <at> gmail.com>
Cc: 33389-done <at> debbugs.gnu.org
Subject: Re: bug#33389: parted not recognizing partitions in "non-standard"
 MBRs with valid partition tables
Date: Tue, 23 Apr 2019 12:42:13 -0400

Unfortunately to figure out what went wrong would require examining the
partition table, which it appears you have destroyed.  If you happened
to have saved a copy and can provide it, please do so and we can reopen
the bug.

Marc Stenson writes:

> Hello,
>
> While parted 2.3 had no issues with whatever was in the first 446 bytes 
> of the MBR and only looked at the partition table, newer versions such 
> as 3.2 seem to be thrown by unusual boot code (e.g. Grub4DOS) and either 
> show the entire disk as unallocated space or as one big volume/partition 
> with the file system of the first volume. This is despite the partition 
> table being fully compliant and happily read by fdisk and sfdisk.
>
> This may be a "feature" rather than a bug.  Please pardon my ignorance, 
> perhaps newer partition table schemes require the first 446 bits to be 
> parsed. However it could save someone many hours of frustration if this 
> was noted prominently in the documentation.
>
> In my case It was fixed with a simple:
>   dd if=/usr/lib/syslinux/mbr/mbr.bin of=/dev/sdb bs=446 count=1
> after taking the requisite backups and a deep breath.
>
> Thanks and regards,
> Marc

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.