[natty] swap not showing uuid

[Dave Gilbert]

Binary package hint: util-linux

This laptop (davros) is running with the natty repository, having been dist-upgraded a few weeks ago from maverick.
(It was installed many versions ago and has worked through many updates).

My swap has gone away (0 shown in all 3 fields in free), and during a boot I (as of about a week ago) gained a warning that the device providing a given UUID was not available and whether I wanted to wait for it. (Actually the other strange symptom was the loss of the ability to hibernate - which makes sense due to the lack of swap)

That UUID that's not available corresponds to the line in my fstab:

# /dev/sda5
UUID=babe3fc2-f612-4961-aa7c-de028b6b883a none swap sw 0 0

yet while /dev/sda5 exists:
grep sda5 /proc/partitions
   8 5 2650693 sda5

there is no entry in /dev/disk/by-uuid for it; using blkid again shows nothing for the device:

root@davros:/dev/disk# blkid -p /dev/sda5
root@davros:/dev/disk#

The following od of /dev/sda5 seems to show the uuid starting at 0002014:

0000000 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0
         00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
0002000 001 \0 \0 \0 220 034 \n \0 \0 \0 \0 \0 272 276 ? 302
         01 00 00 00 90 1c 0a 00 00 00 00 00 ba be 3f c2
0002020 366 022 I a 252 | 336 002 213 k 210 : \0 \0 \0 \0
         f6 12 49 61 aa 7c de 02 8b 6b 88 3a 00 00 00 00
0002040 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0
         00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
0007740 027 ! \0 \0 \0 \0 \0 \0 001 \0 \0 \0 S W A P
         17 21 00 00 00 00 00 00 01 00 00 00 53 57 41 50
0007760 S P A C E 2 L I N H I B 0 0 0 1
         53 50 41 43 45 32 4c 49 4e 48 49 42 30 30 30 31
0010000 3 3 9 \n \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0
         33 33 39 0a 00 00 00 00 00 00 00 00 00 00 00 00
0010020 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0
         00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*

Dave

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: libuuid1 2.17.2-3.3ubuntu1
ProcVersionSignature: Ubuntu 2.6.37-2.10-generic 2.6.37-rc1
Uname: Linux 2.6.37-2-generic x86_64
Architecture: amd64
Date: Sat Nov 27 17:16:20 2010
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
SourcePackage: util-linux

[Dave Gilbert (ubuntu-treblig)]

OK, I think I see what's going on here but I'm not 100% sure.
It looks like the hibernate signature got changed a few months back in the kernel:

http://www.gossamer-threads.com/lists/linux/kernel/1283551

to 'LINHIB0001' which you can see there at offset 4086 (on the line with octal address 0007760)
so I'd say shlibs/blkid/src/superblocks/swap.c needs up dating. I'm not sure if that needs adding to the swsuspend table or
to the swap table - I'm guessing the swsuspend table; but should this signature disappear? Is this only still there because of a failed resume?

Note this also happens with the version of util-linux-ng from git://git.kernel.org/pub/scm/utils/util-linux-ng/util-linux-ng.git rev 07b336c.......7f40a8

Dave