usb-creator-gtk crashed with SIGSEGV in _dbus_header_get_byte_order()

[Coya DeBrojara]

Error while creating a disk image on a USB drive. This error is similar to error #811026. When creating an image, the final time, the program was unexpectedly closed. The image was not properly recorded on the storage medium. USB is good, and has no physical bugs. Ubuntu 12.10.
Błąd podczas tworzenia obrazu dysku na nośniku USB. Ten błąd jest podobny do błędu #811026. Podczas tworzenia obrazu, w końcowym momencie, program został niespodziewanie zamknięty. Obraz nie został poprawnie nagrany na nosniku. Nośnik USB jest sprawny, i nie zawiera fizycznych błędow. Ubuntu 12.10.

ProblemType: Crash
DistroRelease: Ubuntu 12.10
Package: usb-creator-gtk 0.2.40ubuntu1
ProcVersionSignature: Ubuntu 3.5.0-16.25-generic 3.5.4
Uname: Linux 3.5.0-16-generic x86_64
ApportVersion: 2.5.3-0ubuntu1
Architecture: amd64
Date: Sun Sep 30 00:43:42 2012
ExecutablePath: /usr/bin/usb-creator-gtk
InterpreterPath: /usr/bin/python2.7
ProcCmdline: /usr/bin/python /usr/bin/usb-creator-gtk
ProcEnviron:
 PATH=(custom, no user)
 LANG=pl_PL.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x7f24b6b9e7a3: movzbl (%rax),%eax
 PC (0x7f24b6b9e7a3) ok
 source "(%rax)" (0x000007c9) not located in a known VMA region (needed readable region)!
 destination "%eax" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: usb-creator
StacktraceTop:
 ?? () from /lib/x86_64-linux-gnu/libdbus-1.so.3
 ?? () from /lib/x86_64-linux-gnu/libdbus-1.so.3
 dbus_message_get_reply_serial () from /lib/x86_64-linux-gnu/libdbus-1.so.3
 ?? () from /lib/x86_64-linux-gnu/libdbus-1.so.3
 ?? () from /lib/x86_64-linux-gnu/libdbus-1.so.3
Title: usb-creator-gtk crashed with SIGSEGV in dbus_message_get_reply_serial()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo

[Apport retracing service (apport)]

StacktraceTop:
 _dbus_header_get_byte_order (header=header@entry=0x1ae55e8) at ../../dbus/dbus-marshal-header.c:178
 _dbus_header_get_field_basic (header=0x1ae55e8, field=field@entry=5, type=type@entry=117, value=value@entry=0x7ffff74e875c) at ../../dbus/dbus-marshal-header.c:1370
 dbus_message_get_reply_serial (message=<optimized out>) at ../../dbus/dbus-message.c:1091
 _dbus_connection_queue_received_message_link (connection=0x1a9fe60, link=link@entry=0x1aecd10) at ../../dbus/dbus-connection.c:501
 _dbus_transport_queue_messages (transport=0x1a3d1e0) at ../../dbus/dbus-transport.c:1157

[Launchpad Janitor (janitor)]

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

[Fabio Marconi (fabiomarconi)]

reproduced in version 0.2.46.1

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[Fabio Marconi (fabiomarconi)]

creating usb + persistence, full crashfile attached from raring
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[Jan Claeys (janc)]

Observation: when I wait until the LED on my USB flash device stops flickering before entering the password that is required to write the boot record, this crash doesn't happen. It also doesn't crash when I wait "long enough" (not too long before it ends writing).

My guess is that this is related to the famous 64-bit kernel "problem" where writing to a relatively slow USB device means that the whole write operation gets cached in RAM quickly (at which point the write seems finished from the application's PoV, and the USB Creator progress bar also shows that), and then it takes a long time to actually write everything to the USB device. It seems like some dbus call time-outs because it waits until everything is synced to disk before doing what it is supposed to do... (maybe a call to udisks for unmounting or such?).

If my suspicion is true, usb-creator should probably make sure everything it wrote is actually synced to disk before doing whatever it does to write the boot sector?