Ubuntu
unity8 package

[regression] Device locks randomly on welcome screen

Bug #1339700 reported by Dave Morley on 2014-07-09

This bug affects 7 people

	Status	Importance	Assigned to	Milestone
Mir	Fix Released	High	Mir development team	Mir 0.5.0
0.4	Fix Released	High	Mir development team	Mir 0.4.1
mir (Ubuntu)	Fix Released	High	Unassigned
unity8 (Ubuntu)	Invalid	Critical	Unassigned

Bug Description

Unity8 welcome screen will occasionally lock.

Lock effects:
No launcher available
Can't swipe left or right
Can't drag down indicators
Doesn't recover from tapping the power button a couple of times.

Randomness:
Locks so far have been happening on and off from image U114
The phone seems to lock up for me more on waking from suspend, however rsalveti pointed out that for him it happened on phone hang up.

For me the lock happened a couple of times over the weekend images U114 and U115, and then not again till today U122.

Manta seems more prone to lock ups that flo or mako.

STEPS: (It seems flo has an issue identical when opening settings app)
On flo update to U123
1. Once updated, open the settings app
This seems to land you in the state described. Apparently this is only a temporary version if you leave the device for a while it will unlock.

But I think that is possibly because you are moved away from the app and it is unlocked by the system waking from suspend possibly.

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: unity8 7.90+14.10.20140707-0ubuntu1
Uname: Linux 3.4.0-5-mako armv7l
ApportVersion: 2.14.4-0ubuntu1
Architecture: armhf
Date: Wed Jul 9 13:48:14 2014
InstallationDate: Installed on 2014-07-09 (0 days ago)
InstallationMedia: Ubuntu Utopic Unicorn (development branch) - armhf (20140709-020204)
SourcePackage: unity8
UpgradeStatus: No upgrade log present (probably fresh install)

See original description

Tags:

Related branches

lp:~vanvugt/mir/fix-1339700-alarm

Merged into lp:mir at revision 1766

Alberto Aguirre (community): Needs Fixing on 2014-07-11

Andreas Pokorny (community): Approve on 2014-07-11

Alan Griffiths: Approve on 2014-07-11

PS Jenkins bot (community): Approve (continuous-integration) on 2014-07-11

lp:~mir-team/mir/fix-1339700-take2

Merged into lp:mir at revision 1769

PS Jenkins bot (community): Approve (continuous-integration) on 2014-07-14

Chris Halse Rogers: Approve on 2014-07-14

Daniel van Vugt: Approve on 2014-07-14

lp:~vanvugt/mir/fix-1339700-both-0.4

Merged into lp:mir/0.4 at revision 1743

Alexandros Frantzis (community): Approve on 2014-07-14

Cemil Azizoglu (community): Approve on 2014-07-14

lp:ubuntu/utopic-proposed/mir

Revision history for this message

Dave Morley (davmor2) wrote on 2014-07-09:

Dependencies.txt Edit (22.3 KiB, text/plain; charset="utf-8")
ProcEnviron.txt Edit (128 bytes, text/plain; charset="utf-8")
SystemImageInfo.txt Edit (220 bytes, text/plain; charset="utf-8")

Ricardo Salveti (rsalveti) on 2014-07-09

Changed in unity8 (Ubuntu):
status:	New → Confirmed

Revision history for this message

Alan Pope 🍺🐧🐱 🦄 (popey) wrote on 2014-07-09:

I had this today on #119 on mako.

Revision history for this message

Michał Sawicz (saviq) wrote on 2014-07-09:

A bit more info:

- apps can't be launched (hang at startup)
- can't call (display powers up, no sound or notification)
- I couldn't connect from gdb ("A program is being debugged already. Kill it? (y or n)")
- unity8 consumes some CPU (but not a lot, like 14%)
- SIGTERM didn't help
- SIGSEGV didn't result in a .crash file :|

Revision history for this message

Dave Morley (davmor2) wrote on 2014-07-09:

gdb.txt Edit (17.2 KiB, text/plain)

Revision history for this message

Julien Funk (jaboing) wrote on 2014-07-09:

This has been happening to me, more importantly though, when a fix does go in I would like to see an automated test go in along with it.

Revision history for this message

Michał Sawicz (saviq) wrote on 2014-07-09:

More symbols from mzanetti: http://paste.ubuntu.com/7771898/

Revision history for this message

Michał Sawicz (saviq) wrote on 2014-07-09:

Suspicious things from the above (chicken'n'egg possible):

Thread 33: __invoke<mir::scene::SnapshottingFunctor>
Should only be called occasionally, if this locked up, would suggest something in app screenshotting?

Thread 31: SessionAuthorizer::requestAuthorizationForSession
This one should usually only be called on session startup, definitely not when stuff's locked up...

Thread 7: wait<mir::frontend::Surface::swap_buffers_blocking
Should this be there at all? Wonder if this means rendering didn't resume from suspend?

Revision history for this message

Michael Zanetti (mzanetti) wrote on 2014-07-09:

This is the most I could get out of it: http://paste.ubuntu.com/7772064

Revision history for this message

Michał Sawicz (saviq) wrote on 2014-07-09:

My trace out of manta: http://paste.ubuntu.com/7772239/

Revision history for this message

Alberto Aguirre (albaguirre) wrote on 2014-07-09:

#10

Yeah it's a deadlock in mir, specifically between the compositor Thread and the main loop:

The TimeoutFrameDroppingPolicy has timedout, so it owns the internal alarm mutex and attemps to drop a frame, so it waits for the BufferQueue mutex.

The compositor thread is releasing a buffer, so it calls BufferQeueue::compositor_release, which owns the BufferQueue mutex and attempts to update the TimeoutFrameDroppingPolicy (since a buffer is being freed) but it waits to own the internal alarm mutex so deadlock.

Changed in mir:
importance:	Undecided → High
status:	New → Confirmed

Michał Sawicz (saviq) on 2014-07-09

Changed in unity8 (Ubuntu):
status:	Confirmed → Invalid

kevin gunn (kgunn72) on 2014-07-09

Changed in mir:
assignee:	nobody → Alberto Aguirre (albaguirre)

Michał Sawicz (saviq) on 2014-07-09

Changed in mir:
status:	Confirmed → In Progress

Daniel van Vugt (vanvugt) on 2014-07-10

Changed in mir:
milestone:	none → 0.5.0

Revision history for this message

Daniel van Vugt (vanvugt) wrote on 2014-07-10:

#11

The two relevant commits appeared in Mir 0.3.0 and then 0.4.0:

------------------------------------------------------------
revno: 1725 [merge]
committer: Alan Griffiths <email address hidden>
branch nick: development-branch
timestamp: Thu 2014-06-26 17:06:24 +0100
message:
server: Avoid race condition in AlarmImpl
------------------------------------------------------------
...
------------------------------------------------------------
revno: 1675 [merge]
author: Alberto Aguirre <email address hidden>
committer: Tarmac
branch nick: development-branch
timestamp: Tue 2014-06-03 17:49:45 +0000
message:
Allow buffer swapping even when compositor is turned off or blocked. Fixes: https://bugs.launchpad.net/bugs/1308843, https://bugs.launchpad.net/bugs/1308844.

Approved by PS Jenkins bot, Chris Halse Rogers, Kevin DuBois, Alexandros Frantzis.
------------------------------------------------------------

summary:	- Device locks randomly on welcome screen + [regression] Device locks randomly on welcome screen
tags:	added: regression

Revision history for this message

Daniel van Vugt (vanvugt) wrote on 2014-07-10:

#12

Thank you all, BTW, for the lovely stack traces with line number info. That makes things nice and simple...

Daniel van Vugt (vanvugt) on 2014-07-10

Changed in mir:
assignee:	Alberto Aguirre (albaguirre) → Mir development team (mir-team)

Dave Morley (davmor2) on 2014-07-10

description:

updated

Daniel van Vugt (vanvugt) on 2014-07-11

Changed in mir (Ubuntu):
status:	New → Triaged
importance:	Undecided → High

Cemil Azizoglu (cemil-azizoglu) on 2014-07-11

tags:

added: rtm14

Revision history for this message

PS Jenkins bot (ps-jenkins) wrote on 2014-07-11:

#13

Fix committed into lp:mir/devel at revision None, scheduled for release in mir, milestone Unknown

Changed in mir:
status:	In Progress → Fix Committed

Alberto Aguirre (albaguirre) on 2014-07-11

Changed in mir:
status:	Fix Committed → In Progress

Daniel van Vugt (vanvugt) on 2014-07-14

Changed in mir:
status:	In Progress → Fix Committed

Daniel van Vugt (vanvugt) on 2014-07-14

Changed in mir:
status:	Fix Committed → In Progress

PS Jenkins bot (ps-jenkins) on 2014-07-14

Changed in mir:
status:	In Progress → Fix Committed

Revision history for this message

Launchpad Janitor (janitor) wrote on 2014-07-14:

#15

This bug was fixed in the package mir - 0.4.1+14.10.20140714-0ubuntu1

---------------
mir (0.4.1+14.10.20140714-0ubuntu1) utopic; urgency=medium

  [ Daniel van Vugt ]
  * Bug fix release 0.4.1 (https://launchpad.net/mir/+milestone/0.4.1) fixes:
    - [regression] Device locks randomly on welcome screen (LP: #1339700)
-- Ubuntu daily release <email address hidden> Mon, 14 Jul 2014 13:13:37 +0000

Changed in mir (Ubuntu):
status:	Triaged → Fix Released

Revision history for this message

Marc Feddersen (marc-feddersen) wrote on 2014-07-14:

#16

FWIW, it seems after OTA updates this issue happens more often.

After running (r119, manta):
$ ubuntu-device-flash --channel=devel
I had no trouble with this issue lately. :-)

Revision history for this message

Daniel van Vugt (vanvugt) wrote on 2014-07-15:

#17

Yeah image 119 only has Mir 0.4.0 so doesn't have the fix for this yet. Wait a day or so I guess and the mir packages upgrade to 0.4.1.

Cemil Azizoglu (cemil-azizoglu) on 2014-07-18

Changed in mir:
status:	Fix Committed → Fix Released

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Ubuntuunity8 package

[regression] Device locks randomly on welcome screen

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Ubuntu
unity8 package