Comment 145 for bug 1674838

You are right. This is NOT the same bug but stunningly happens with this kernel while the "share + more actions" on firefox worked fine with the ubuntu kernel.

Here is the relevant entry in the syslog:

May 11 16:40:30 Murat-Laptop dbus-daemon[1834]: Activating service name='org.gnome.GConf'
May 11 16:40:30 Murat-Laptop dbus-daemon[1834]: Successfully activated service 'org.gnome.GConf'
May 11 16:40:32 Murat-Laptop unity-panel-ser[2370]: Already have a menu for window ID 65011728 with path /com/canonical/menu/3E00010 from :1.106, unregistering that one
May 11 16:40:32 Murat-Laptop unity-panel-ser[2370]: Already have a menu for window ID 65011728 with path /com/canonical/menu/3E00010 from :1.106, unregistering that one
May 11 16:40:33 Murat-Laptop compiz[2359]: 1494535233840#011FirefoxAccounts#011ERROR#011Background refresh of profile failed, bumping _cachedAt: {"name":"FxAccountsProfileClientError","code":3
04,"errno":997,"error":"PARSE_ERROR","message":null}
May 11 16:40:34 Murat-Laptop systemd[1]: Starting Stop ureadahead data collection...
May 11 16:40:34 Murat-Laptop systemd[1]: Started Stop ureadahead data collection.
May 11 16:40:56 Murat-Laptop compiz[2359]: Vector smash protection is enabled.
May 11 16:48:54 Murat-Laptop unity-panel-ser[2370]: Already have a menu for window ID 67109067 with path /com/canonical/menu/40000CB from :1.113, unregistering that one

There is 8 minutes of silence after the crash between 16:40 and 16:48, where I instinctively pressed alt+sysrqE to failure of reboot!

I CAN reproduce this particular error, which clearly is NOT the bug we are dealing with on this thread, following the same steps. Actually you can try this by clicking on "Share this page" icon on firefox and then the + icon to install more social actions.

You CAN kill the stalled Firefox processs from a terminal.