Ubuntu

Partitions of SSD (MBR) misrecognized

Asked by Dimos Dimoulis

I am having trouble installing Ubuntu on a newly built system (M/B: Gigabyte B85M-HD3, SSD: Transcend 370 128GB)
The disk was partitioned with Windows installer (Windows 7) with the legacy BIOS (MBR) setting
However the two partitions created by Windows are seen as corrupt by Ubuntu installer disk.
ls /dev/sda* only shows "/dev/sda /dev/sda1" and not /dev/sda2 (sda1 is windows boot partition and sda2 its main partition)
gparted says /dev/sda1 is lacking NTFS signature and /dev/sda2 doesn't exist

This behavior appears in both Ubuntu 15.04 and 14.04.2
However:
Both partitions are correctly recognized and mounted by every other linux distribution I have tried (Arch installer of April 2015, Linux Mint 17.1, Crunchbang). Windows works fine as well.

This seems like an Ubuntu specific bug. Any idea to get around it and enable me to install Ubuntu instead?

Output of fdisk -l
Disk /dev/sda: 119.2 GiB, 128035676160 bytes, 250069680 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xe4e835e9

Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 206847 204800 100M 7 HPFS/NTFS/exFAT
/dev/sda2 206848 250066943 249860096 119.1G 7 HPFS/NTFS/exFAT

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Dimos Dimoulis
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actionparsnip (andrew-woodhead666) said : 		#1

Have you ran a chkdsk on your NTFS partitions to make sure they are consistant and complete?

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Dimos Dimoulis (dimosd) said : 		#2

A relevant fragment from dmesg:
[ 3.326601] sd 0:0:0:0: [sda] 250069680 512-byte logical blocks: (128 GB/119 GiB)
[ 3.326680] sd 0:0:0:0: [sda] Write Protect is off
[ 3.326683] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
[ 3.326705] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 3.327072] sda: [CUMANA/ADFS] sda1 [ADFS] sda1
[ 3.327076] sda: partition table partially beyond EOD, enabling native capacity
[ 3.340753] sda: [CUMANA/ADFS] sda1 [ADFS] sda1
[ 3.340754] sda: partition table partially beyond EOD, truncated
[ 3.340756] sda: p1 size 4067027304 extends beyond EOD, truncated
[ 3.340929] sd 0:0:0:0: [sda] Attached SCSI disk

I compared this to dmesg I get from booting Arch installer and the lines about "partition table partially beyond EOD, truncated" don't appear there. Instead I see something like
[ 3.448351] sda: sda1 sda2
[ 3.448597] sd 0:0:0:0: [sda] Attached SCSI disk
and the partitions are recognized
It looks to me like a signed/unsigned overflow bug from a patch applied to Ubuntu kernel. Any ideas how to proceed?

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Dimos Dimoulis (dimosd) said : 		#3

Found this: https://bugzilla.kernel.org/show_bug.cgi?id=4054

"This is a consequence of enabling CONFIG_ACORN_PARTITION_CUMANA:
a 1 in 256 probability of getting any random partition recognized
as CUMANA/ADFS. Solution: do not enable CONFIG_ACORN_PARTITION_CUMANA."

I will report this as a bug

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Cyril Auboin (1-cyril) said : 		#4

Hello, I had the very same problem with my raspbery SD card that I wanted to mount on my ubuntu 14.04 laptop.
I found a workaround that wotks for me:

As root, type partprobe /dev/sdb (sdb is my SD card)
(or sudo)
after that, all partitions are recognized!!

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Dimos Dimoulis (dimosd) said : 		#5

Thanks for answering. Since the partitions are recognized by all other distributions except Ubuntu, I am pretty sure this is an Ubuntu related bug. I will not risk corrupting the otherwise working partition table.

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actionparsnip (andrew-woodhead666) said : 		#6

Did you chkdsk the NTFS partitions?

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Cyril Auboin (1-cyril) said : 		#7

this has nothing to do with NTFS. I had the same problem with a FAT partition+an ext4 partition (raspberry pi sd card)

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Cyril Auboin (1-cyril) said : 		#8

and all filesystems were clean

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Dimos Dimoulis (dimosd) said : 		#9

After repartitioning from Windows to add a Linux partition, the Ubuntu installer can now properly read all partitions.

However, this was a "lucky" fix. The problem was likely caused by a known bug in the adfs module (about an old Acorn filesystem nobody uses anymore).

If anyone else runs into similar problems with [CUMANA/ADFS] messages in dmesg, I suggest you try blacklisting the adfs kernel module.