parted_server crashed with SIGSEGV in __libc_start_main()

[Peter Hurley]

Crash with amd64 desktop iso of 4/4/12.

Boot from DVD, select 'Try Ubuntu', then 'Install Ubuntu 12.04'. Occurs after selecting 'Continue' from the 'Preparing to install Ubuntu'.

Hopefully the problem with mismatched debug symbols has been fixed :)

ProblemType: Crash
DistroRelease: Ubuntu 12.04
Package: ubiquity 2.10.6
ProcVersionSignature: Ubuntu 3.2.0-21.34-generic 3.2.13
Uname: Linux 3.2.0-21-generic x86_64
ApportVersion: 2.0-0ubuntu4
Architecture: amd64
CasperVersion: 1.314
Date: Wed Apr 4 14:42:28 2012
ExecutablePath: /bin/parted_server
InstallCmdLine: file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash -- maybe-ubiquity
LiveMediaBuild: Ubuntu 12.04 LTS "Precise Pangolin" - Beta amd64 (20120404)
ProcCmdline: parted_server
ProcEnviron:
 TERM=unknown
 LC_COLLATE=C
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: ubiquity
StacktraceTop:
 ?? ()
 ?? ()
 ?? ()
 __libc_start_main () from /lib/x86_64-linux-gnu/libc.so.6
 ?? ()
Title: parted_server crashed with SIGSEGV in __libc_start_main()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:

[Apport retracing service (apport)]

Thank you for your report!

However, processing it in order to get sufficient information for the
developers failed (it does not generate a useful symbolic stack trace). This
might be caused by some outdated packages which were installed on your system
at the time of the report:

outdated debug symbol package for dmidecode: package version 2.11-4 dbgsym version 2.9-1.2build1
outdated debug symbol package for cryptsetup: package version 2:1.4.1-2ubuntu2 dbgsym version 2:1.1.3-4ubuntu2

Please upgrade your system to the latest package versions. If you still
encounter the crash, please file a new report.

Thank you for your understanding, and sorry for the inconvenience!

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/973450

[Steve Langasek (vorlon)]

Unfortunately, it looks like we still don't have a full stack trace for this. Since the problem is not widely reproducible, we are unlikely to be able to debug this without a stack trace.

Can you install the -dbgsym packages in the live environment before starting the installer, and generate a full backtrace locally?

[Peter Hurley (phurley)]

Hi Steve,

I can but not until Monday or Tuesday of next week.

[Peter Hurley (phurley)]

Hi Steve,

What -dbgsym packages can I install locally to get a valid stack trace???

FYI - The outdated debug symbol packages I've reported on a separate bug# 962479 against apport which Martin just invalidated. He stated that it's due to outdated binary packages but that doesn't make sense -- dmidecode is still at 2.11-4 !!

[Peter Hurley (phurley)]

Ok, here's the situation:

There is no stack backtrace because there is no debug symbol package for parted_server (which is a binary produced from ubiquity source package in d-i/source/partman-base/parted_server.c)

Despite that, simply loading parted_server in gdb and disassembling at the fault address was sufficient to uncover the faulting code. In parted_server.c::command_get_file_system(), the following line will fault if fs_type == NULL:
                        if (0 == strncmp(part->fs_type->name, "linux-swap", 10))

Although this should be fixed, there is a larger problem that is contributing to this: the scripts feeding the parted_server are mistaking /dev/mapper partitions as devices.

Here's the output from parted_devices on my machine:
peter@thor:~/src/packages/ubiquity/ubiquity-2.10.8/d-i/source/partman-base$ sudo ./parted_devices
[sudo] password for peter:
/dev/sda 1000204886016 ATA WDC WD1001FALS-0
/dev/sdb 1000204886016 ATA WDC WD1001FALS-0
/dev/sdc 250000000000 ATA ST3250310AS
/dev/sdd 160041885696 Seagate FreeAgent Go
/dev/mapper/isw_cbdbfhdjad_Raid0p6 940568928768 Linux device-mapper (linear)
/dev/mapper/isw_cbdbfhdjad_Raid0p1 1048575112704 Linux device-mapper (linear)
/dev/mapper/isw_cbdbfhdjad_Raid0p5 11260376064 Linux device-mapper (linear)
/dev/mapper/isw_cbdbfhdjad_Raid0p2 951829338112 Linux device-mapper (linear)
/dev/mapper/isw_cbdbfhdjad_Raid0 2000405397504 Linux device-mapper (striped)

Now, if you look at the partman log attached to this bug report, you'll see that parted_server is being fed the /dev/mapper/...._Raid0p2, for example, as a device. This is *way wrong* -- look at the crazy partition table it came up with for this "device":

/lib/partman/init.d/35dump: IN: DUMP =dev=mapper=isw_cbdbfhdjad_Raid0p2
parted_server: Read command: DUMP
parted_server: command_dump()
parted_server: Opening outfifo
parted_server: OUT: OK

parted_server: Closing infifo and outfifo
parted_server: main_loop: iteration 20
parted_server: Opening infifo
Device: yes
Model: Linux device-mapper (linear)
Path: /dev/mapper/isw_cbdbfhdjad_Raid0p2
Sector size: 512
Sectors: 1859041676
Sectors/track: 63
Heads: 255
Cylinders: 115719
Partition table: yes
Type: msdos
Partitions: # id length type fs path name
(0,0,0) (0,0,1) -1 0-1023 1024 primary label /dev/mapper/isw_cbdbfhdjad_Raid0p2p-1
(0,0,2) (114350,253,1) 2 1024-940568929791 940568928768 primary extended /dev/mapper/isw_cbdbfhdjad_Raid0p2p2
(0,0,2) (114350,253,1) 5 1024-940568929791 940568928768 logical ext4 /dev/mapper/isw_cbdbfhdjad_Raid0p2p5
(114350,253,2) (114350,254,1) -1 940568929792-940568962047 32256 pri/log free /dev/mapper/isw_cbdbfhdjad_Raid0p2p-1
(114350,254,2) (115719,253,1) 1 940568962048-951829338111 11260376064 primary linux-swap /dev/mapper/isw_cbdbfhdjad_Raid0p2p1
Dump finished.

This mishandling of fakeraid partitions should be easily reproducible on any fakeraid machine.

FYI - the "outdated debug symbol packages" bug is a red herring. No stack trace is possible because there are no debug symbol packages for parted_server.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Peter Hurley (phurley)]

Still broken on quantal....

[Marcus Tomlinson (marcustomlinson)]

This release of Ubuntu is no longer receiving maintenance updates. If this is still an issue on a maintained version of Ubuntu please let us know.

[Launchpad Janitor (janitor)]

[Expired for ubiquity (Ubuntu) because there has been no activity for 60 days.]