unity8 crashed with SIGSEGV in UnityMenuModelPrivate::itemState()

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #1234737, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.

I got a slightly better stacktrace than what's available in the linked bug, see attachment.

assigning to lars as per discussion in #ubuntu-touch

Turns out this is a bug in unity8 after all. The UnityMenuModel is given a pointer to an ActionStateParser that is invalidated without telling the model.

The attached branch fixes the problem half-way: unity8 doesn't crash anymore when enabling and disabling bluetooth successively. However, the bluetooth indicator doesn't show up after the first disable / enable cylce. Nick, could you please have a look at that?

@larsu.
It seems as though turning bluetooth on after it's been turned off doesn't actually work.

phablet@ubuntu-phablet:~$ hciconfig
hci0: Type: BR/EDR Bus: UART
 BD Address: 38:0A:94:2F:17:5D ACL MTU: 1021:8 SCO MTU: 64:1
 UP RUNNING PSCAN
 RX bytes:893 acl:0 sco:0 events:37 errors:0
 TX bytes:936 acl:0 sco:0 commands:37 errors:0

* DISABLED IN SETTINGS APP.

phablet@ubuntu-phablet:~$ hciconfig
hci0: Type: BR/EDR Bus: UART
 BD Address: 38:0A:94:2F:17:5D ACL MTU: 1021:8 SCO MTU: 64:1
 DOWN
 RX bytes:900 acl:0 sco:0 events:38 errors:0
 TX bytes:949 acl:0 sco:0 commands:39 errors:0

* ENABLED IN SETTINGS APP.

phablet@ubuntu-phablet:~$ hciconfig
hci0: Type: BR/EDR Bus: UART
 BD Address: 38:0A:94:2F:17:5D ACL MTU: 1021:8 SCO MTU: 64:1
 DOWN INIT RUNNING
 RX bytes:900 acl:0 sco:0 events:38 errors:0
 TX bytes:961 acl:0 sco:0 commands:42 errors:0

* A FEW SECONDS LATER.

phablet@ubuntu-phablet:~$ hciconfig
hci0: Type: BR/EDR Bus: UART
 BD Address: 38:0A:94:2F:17:5D ACL MTU: 1021:8 SCO MTU: 64:1
 DOWN
 RX bytes:907 acl:0 sco:0 events:38 errors:0
 TX bytes:999 acl:0 sco:0 commands:49 errors:0

Running "rfkill unblock bluetooth" has same effect. Looks like it tries to enable, then fails.

The ubuntu-system-settings and indicator-bluetooth branches I've linked here attempt to handle things more gracefully whenever indicator-bluetooth can't work with /dev/rfkill -- it attempts to fall back to just calling org.bluez.Adapter::SetProperties("Powered", on/off)

This is an improvement; unfortunately, it doesn't seem to be a complete fix yet as powering on/off on the desktop is unreliable in the latest nightlies, even when using bluez' command-line utilities to power off & on again. I've filed that separate issue as bug #1238672

This bug was fixed in the package ubuntu-system-settings - 0.1+13.10.20131015-0ubuntu1

---------------
ubuntu-system-settings (0.1+13.10.20131015-0ubuntu1) saucy; urgency=low

  [ Charles Kerr ]
  * In the battery plugin, use indicator-bluetooth's "bluetooth-
    supported" action state to know whether or not to show the bluetooth
    toggle. (LP: #1233628)
  * In the bluetooth plugin, handle bluetooth adapters
    appearing/disappearing on the bus. (LP: #1236249)

  [ Sebastien Bacher ]
  * update: get the current build number, use it in the os version
    string. (LP: #1233682)
  * update: tweak a bit the UI, we don't have a description for the
    updates so there is no need to keep the stacked UI, we can use one
    line. Copy the icon in the source as well since it's not installed
    on touch. (LP: #1233682)
  * sound: use the new sounds sets from ubuntu-touch-sounds.

  [ Ubuntu daily release ]
  * Automatic snapshot from revision 456
 -- Ubuntu daily release <email address hidden> Tue, 15 Oct 2013 04:19:09 +0000

Fix committed into lp:indicator-bluetooth at revision 70, scheduled for release in indicator-bluetooth, milestone Unknown

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

This bug was fixed in the package indicator-bluetooth - 0.0.6+13.10.20131016-0ubuntu1

---------------
indicator-bluetooth (0.0.6+13.10.20131016-0ubuntu1) saucy; urgency=low

  [ Charles Kerr ]
  * When the user chooses to toggle bluetooth on or off, if /dev/rfkill
    isn't available, fall back to toggling org.bluez.Adapter's Powered
    property. (LP: #1236249, #1230275)

  [ Ubuntu daily release ]
  * Automatic snapshot from revision 70
 -- Ubuntu daily release <email address hidden> Wed, 16 Oct 2013 02:34:31 +0000