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On 2011-07-27T18:12:38+00:00 Mikhail Titov wrote:

Created attachment 49623
udevadm info --export-db

Probably some non-free partitioning tools produce nested though valid
partition scheme involving nested partitions. That is there is a
reference for extended partition of type 0x0f in MBR that refers to
another partition (/dev/sda2 in my case) that has only single record in
EBR of type 0x05 and all other extended partition are within that and
are not linked from very first EBR.

This leads to incorrect report of valid partitions as if they have
partition type 0x05. This breaks some things in gnome environment in
particular like https://bugs.launchpad.net/ubuntu/+source/gnome-disk-
utility/+bug/571038 .

I'm running udisks 1.0.2, gvfs 1.8.0, no libatasmart installed

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/31

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On 2011-07-27T18:13:07+00:00 Mikhail Titov wrote:

Created attachment 49624
/etc/fstab

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/32

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On 2011-07-27T18:13:35+00:00 Mikhail Titov wrote:

Created attachment 49625
udisks dump

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/33

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On 2011-07-27T18:14:37+00:00 Mikhail Titov wrote:

Created attachment 49626
cat /proc/self/mountinfo

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/34

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On 2011-07-27T18:15:40+00:00 Mikhail Titov wrote:

Created attachment 49627
sfdisk -l

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/35

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On 2011-07-28T03:42:40+00:00 Mikhail Titov wrote:

Created attachment 49636
some changes

I'm not familiar with the code well and this patch is far from being
final. It is just to demonstrate the issue. It helps to discover some
other partitions. Also it reports correct partition type for my
/dev/sda5 i.e. 0x83 instead of 0x05 .

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/36

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On 2011-07-28T03:44:52+00:00 Mikhail Titov wrote:

Created attachment 49637
./udisks-part-id /dev/sda5 > log 2>&1

This is what I'm getting after that patch. Someone should double check
everything as I'm not that big expert in EBR.

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/37

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On 2011-07-28T04:00:14+00:00 Mikhail Titov wrote:

Created attachment 49642
/lib/udev/udisks-part-id /dev/sda5 > /tmp/udisks_part_id_original.txt 2>&1

This is for comparison with previous one. You can see that original
report 0x05 for my root on /dev/sda5 and this make libgdu to confuse a
lot.

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/39

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On 2011-07-28T04:12:42+00:00 Mikhail Titov wrote:

Created attachment 49644
hexdump enabled ./probers/udisks-part-id /dev/sda5 > /tmp/udisks_hexdump.txt 
2>&1

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/40

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On 2011-07-28T04:22:24+00:00 Mikhail Titov wrote:

Comment on attachment 49644
hexdump enabled ./probers/udisks-part-id /dev/sda5 > /tmp/udisks_hexdump.txt 
2>&1

While second hexdump looks like mbr, in fact it is not. Also note that
consequent ebr points to another ebr using partition type 0x05 again.
That is crazy!

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/41

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On 2011-07-28T05:45:16+00:00 Mikhail Titov wrote:

Created attachment 49646
slightly rewritten patch but still not final

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/42

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On 2011-07-28T05:50:25+00:00 Mikhail Titov wrote:

Created attachment 49647
./probers/udisks-part-id /dev/sda6 > /tmp/udisks_part_id_sda6.txt 2>&1

This is an attempt to get info for /dev/sda6 . part-id failed to find
/dev/sda6 at 142856695296 , however patched parser found yet another
extended partition 0x05 at 142856694784 just one sector (512 bytes)
ahead.

mlt@nb:~/workspace/udisks/src$ fdisk -lu
omitting empty partition (5)

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders, total 312581808 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
Disk identifier: 0x046a411b

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *          63   192008879    96004408+   7  HPFS/NTFS
/dev/sda2       192008880   312581807    60286464    f  W95 Ext'd (LBA)
/dev/sda5       192008943   279016919    43503988+  83  Linux
/dev/sda6       279016983   306279224    13631121    7  HPFS/NTFS
/dev/sda7       306290136   312581807     3145836   82  Linux swap / Solaris

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/43

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On 2011-07-28T05:53:01+00:00 Mikhail Titov wrote:

(In reply to comment #11)
> Created an attachment (id=49647) [details]
> ./probers/udisks-part-id /dev/sda6 > /tmp/udisks_part_id_sda6.txt 2>&1
> 
> This is an attempt to get info for /dev/sda6 . part-id failed to find 
> /dev/sda6
> at 142856695296 , however patched parser found yet another extended partition
> 0x05 at 142856694784 just one sector (512 bytes) ahead.

Note pstart = 512 before the last hexdump when it failed to find
signature! Those pstart must be relative to that nested extended
partition.

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/44

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On 2011-07-28T06:58:59+00:00 Mikhail Titov wrote:

Created attachment 49650
And that is all that was missing :-)

In some cases EBR has only a single non-zero entry that should be
interpreted as a link.

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/45

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On 2012-03-28T13:28:45+00:00 Martin Pitt wrote:

Mikhail, thanks a lot for your help here!

I have tried for an hour to replicate such a nested partition layout,
but haven't succeeded so far. The easiest and safest is to do "sudo
modprobe scsi_debug" and use the new virtual 8 MB device for this. I
used sfdisk and fdisk trying to recreate such a structure, but no luck.
Did you happen to succeed with this? If you have a small device with no
actual data, it might also be possible to just dd it and compress the
dump.

I'd like to be able to reproduce this to put it into udisks' test suite.
Both udisks 1.x and libgdu (where this crash happens) are being
deprecated, and I'd rather ensure that this bug does not happen again
with udisks 2, or whatever the replacement will be in 5 years.

Thanks!

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/69

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On 2012-03-28T13:57:33+00:00 Martin Pitt wrote:

Oh, I just happened to crash gvfs-gdu-volume-monitor with that very
problem (https://bugzilla.gnome.org/show_bug.cgi?id=622066). Now I need
to find a way to reliably reproduce it..

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/70

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On 2012-03-28T15:10:08+00:00 Martin Pitt wrote:

Sorry, I've been trying for 3.5 hours now, and I'm unable to reproduce
this. Perhaps someone else has more luck than me?

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/71

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On 2012-03-28T19:44:47+00:00 Mikhail Titov wrote:

@Martin

I did not know about scsi_debug. I'll see what I can do. But it is
likely going to be later this week. And I have to unpatch udisk to
actually reproduce it:-)

Otherwise, try creating few logical partitions, then discard offset
pointers and replace those with the link pointing to the next partition.
In terms of [1] just copy data for "Partition table's second entry" in
place of "Partition table's first entry" and fill the former with 00s.
You'll actually waste space on disk that was allocated for that
partition. I guess GNU/Linux tools are smart enough not to insert such
unnecessary stuff if you try to create 0 sized partition.

I have my dumps of my EMBR attached [2] within this post.

[1] http://en.wikipedia.org/wiki/Extended_boot_record
[2] https://bugs.freedesktop.org/attachment.cgi?id=49647

Reply at: https://bugs.launchpad.net/gnome-disk-
utility/+bug/571038/comments/72


** Changed in: udisks
       Status: Unknown => Confirmed

** Changed in: udisks
   Importance: Unknown => Medium

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Title:
  palimpsest crash with libgdu:ERROR:gdu-pool.c:2369:device_recurse:
  assertion failed: (depth < 100)

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