I think this is an issue with the lightdm(-guest-session) apparmor profiles.
In dmesg: laney@yakkety-vm:~$ dmesg | grep DENIED [ 142.273990] audit: type=1400 audit(1474905574.718:125): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/sys/kernel/osrelease" pid=2167 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 142.274396] audit: type=1400 audit(1474905574.718:126): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/1/cmdline" pid=2167 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 142.274428] audit: type=1400 audit(1474905574.718:127): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/2/cmdline" pid=2167 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 142.274457] audit: type=1400 audit(1474905574.718:128): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/3/cmdline" pid=2167 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 142.274484] audit: type=1400 audit(1474905574.718:129): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/4/cmdline" pid=2167 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 142.274513] audit: type=1400 audit(1474905574.718:130): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/5/cmdline" pid=2167 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 142.274542] audit: type=1400 audit(1474905574.718:131): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/6/cmdline" pid=2167 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 142.274569] audit: type=1400 audit(1474905574.718:132): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/7/cmdline" pid=2167 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 142.274598] audit: type=1400 audit(1474905574.718:133): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/8/cmdline" pid=2167 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 142.274626] audit: type=1400 audit(1474905574.718:134): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/9/cmdline" pid=2167 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 147.434462] audit: type=1400 audit(1474905579.878:282): apparmor="DENIED" operation="connect" profile="/usr/lib/lightdm/lightdm-guest-session" pid=2843 comm="initctl" family="unix" sock_type="stream" protocol=0 requested_mask="send receive accept" denied_mask="send accept" addr="@/com/ubuntu/upstart-session/998/2526" peer_addr=none peer="unconfined" [ 147.450970] audit: type=1400 audit(1474905579.894:283): apparmor="DENIED" operation="connect" profile="/usr/lib/lightdm/lightdm-guest-session" pid=2855 comm="initctl" family="unix" sock_type="stream" protocol=0 requested_mask="send receive accept" denied_mask="send accept" addr="@/com/ubuntu/upstart-session/998/2526" peer_addr=none peer="unconfined" [ 147.494563] audit: type=1400 audit(1474905579.938:284): apparmor="DENIED" operation="connect" profile="/usr/lib/lightdm/lightdm-guest-session" pid=2871 comm="initctl" family="unix" sock_type="stream" protocol=0 requested_mask="send receive accept" denied_mask="send accept" addr="@/com/ubuntu/upstart-session/998/2526" peer_addr=none peer="unconfined" [ 147.511922] audit: type=1400 audit(1474905579.954:285): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/sys/kernel/osrelease" pid=2879 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 147.512279] audit: type=1400 audit(1474905579.958:286): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/1/cmdline" pid=2879 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 147.512303] audit: type=1400 audit(1474905579.958:287): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/2/cmdline" pid=2879 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 147.512322] audit: type=1400 audit(1474905579.958:288): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/3/cmdline" pid=2879 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 147.512340] audit: type=1400 audit(1474905579.958:289): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/4/cmdline" pid=2879 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 147.512356] audit: type=1400 audit(1474905579.958:290): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/5/cmdline" pid=2879 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 [ 147.512373] audit: type=1400 audit(1474905579.958:291): apparmor="DENIED" operation="open" profile="/usr/lib/lightdm/lightdm-guest-session" name="/proc/6/cmdline" pid=2879 comm="pkill" requested_mask="r" denied_mask="r" fsuid=998 ouid=0 In the journal: Sep 26 16:59:39 yakkety-vm systemd[2518]: Starting Unity Shell v7... Sep 26 16:59:39 yakkety-vm kernel: audit_printk_skb: 441 callbacks suppressed Sep 26 16:59:39 yakkety-vm kernel: audit: type=1400 audit(1474905579.878:282): apparmor="DENIED" operation="connect" profile="/usr/lib/lightdm/lightdm-guest-session" pid=2843 comm="initctl" family=" Sep 26 16:59:39 yakkety-vm systemd[2518]: Started GNOME Session Manager. Sep 26 16:59:39 yakkety-vm sh[2846]: + [ ubuntu != gnome-classic ] Sep 26 16:59:39 yakkety-vm sh[2846]: + [ ubuntu = gnome-flashback-metacity ] Sep 26 16:59:39 yakkety-vm sh[2846]: + exec gnome-session --session=ubuntu Sep 26 16:59:39 yakkety-vm audit[2855]: AVC apparmor="DENIED" operation="connect" profile="/usr/lib/lightdm/lightdm-guest-session" pid=2855 comm="initctl" family="unix" sock_type="stream" protocol=0 Sep 26 16:59:39 yakkety-vm systemd-prestart-check[2845]: initctl: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart-session/998/2526: Permission denied Sep 26 16:59:39 yakkety-vm kernel: audit: type=1400 audit(1474905579.894:283): apparmor="DENIED" operation="connect" profile="/usr/lib/lightdm/lightdm-guest-session" pid=2855 comm="initctl" family=" Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: OpenGL vendor string: VMware, Inc. Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: OpenGL renderer string: Gallium 0.4 on llvmpipe (LLVM 3.8, 256 bits) Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: OpenGL version string: 3.0 Mesa 12.0.1 Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: Not software rendered: no Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: Not blacklisted: yes Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: GLX fbconfig: yes Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: GLX texture from pixmap: yes Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: GL npot or rect textures: yes Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: GL vertex program: yes Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: GL fragment program: yes Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: GL vertex buffer object: yes Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: GL framebuffer object: yes Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: GL version is 1.4+: yes Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: Unity 3D supported: no Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: Using compiz profile 'ubuntu-lowgfx' Sep 26 16:59:39 yakkety-vm audit[2871]: AVC apparmor="DENIED" operation="connect" profile="/usr/lib/lightdm/lightdm-guest-session" pid=2871 comm="initctl" family="unix" sock_type="stream" protocol=0 Sep 26 16:59:39 yakkety-vm compiz-profile-selector[2861]: initctl: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart-session/998/2526: Permission denied Sep 26 16:59:39 yakkety-vm systemd[2518]: unity7.service: Control process exited, code=exited status=1 Sep 26 16:59:39 yakkety-vm systemd[2518]: Failed to start Unity Shell v7. Sep 26 16:59:39 yakkety-vm systemd[2518]: Dependency failed for User systemd services for the Ubuntu graphical session. Sep 26 16:59:39 yakkety-vm systemd[2518]: ubuntu-session.target: Job ubuntu-session.target/start failed with result 'dependency'. Sep 26 16:59:39 yakkety-vm systemd[2518]: unity7.service: Unit entered failed state. Sep 26 16:59:39 yakkety-vm kernel: audit: type=1400 audit(1474905579.938:284): apparmor="DENIED" operation="connect" profile="/usr/lib/lightdm/lightdm-guest-session" pid=2871 comm="initctl" family=" Sep 26 16:59:39 yakkety-vm systemd[2518]: unity7.service: Failed with result 'exit-code'. ** Also affects: apparmor (Ubuntu) Importance: Undecided Status: New ** Tags added: rls-y-incoming ** Changed in: gnome-session (Ubuntu) Status: Confirmed => Incomplete ** Changed in: lightdm (Ubuntu) Status: Confirmed => Incomplete ** Changed in: lightdm (Ubuntu) Status: Incomplete => Triaged ** Changed in: lightdm (Ubuntu) Importance: Undecided => Critical ** Changed in: apparmor (Ubuntu) Importance: Undecided => Critical ** Changed in: apparmor (Ubuntu) Status: New => Triaged ** Changed in: unity-greeter (Ubuntu) Status: Confirmed => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1627304 Title: User locking problems - guest login crashing To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/apparmor/+bug/1627304/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs