Unity crashes with lots of music displayed in expanded music category in home scope

Could you get us a .crash file maybe?
I strongly suspect this is a dupe of bug #1240408.

Crash file

I can also trigger a crash by simply scrolling through the carosel in the music scope

I have 14 tracks installed and see no crashes here. However after I will start to add some extra ones and see if the system dies.

Same signature as the two duplicates, all related to fetching album art. I suspect this to be caused by the album art provider being called in parallel by multiple images (since all of them are very close to each other in the scope) and that gets it to die.

If you have all your media art, it won't crash, rm ~/.cache/media-art/* to purge them and play in the dash again.

Got a not-really-helpful symbolic stacktrace:

Program received signal SIGSEGV, Segmentation fault.
QCoreApplication::postEvent (receiver=receiver@entry=0x9ffa5ba0, event=0xa0519de8, priority=priority@entry=0)
    at kernel/qcoreapplication.cpp:1230
1230 kernel/qcoreapplication.cpp: Nie ma takiego pliku ani katalogu.
(gdb) bt full
#0 QCoreApplication::postEvent (receiver=receiver@entry=0x9ffa5ba0, event=0xa0519de8,
    priority=priority@entry=0) at kernel/qcoreapplication.cpp:1230
        __PRETTY_FUNCTION__ = "static void QCoreApplication::postEvent(QObject*, QEvent*, int)"
        data = <optimized out>
        locker = <optimized out>
        pdata = 0x25
        eventDeleter = <optimized out>
        dispatcher = 0x9ffa5ba0
#1 0xb6957ca0 in QQuickPixmapReply::postReply (this=this@entry=0x9ffa5ba0,
    error=error@entry=QQuickPixmapReply::NoError, errorString=..., implicitSize=..., factory=0x9fa06f10)
    at util/qquickpixmapcache.cpp:323
No locals.
#2 0xb6959fac in QQuickPixmapReader::processJob (this=this@entry=0xa8805fc8,
    runningJob=runningJob@entry=0x9ffa5ba0, url=..., requestSize=...) at util/qquickpixmapcache.cpp:566
        image = {<QPaintDevice> = {_vptr.QPaintDevice = 0xb6fc66a8 <vtable for QImage+8>, painters = 0,
            reserved = 0x0}, d = 0x9fe7c7b0}
        errorCode = QQuickPixmapReply::NoError
        errorStr = {static null = {<No data fields>}, d = 0xb678e9cc <QArrayData::shared_null>}
        readSize = {wd = 96, ht = 96}
        imageType = <optimized out>
        provider = 0xac164f58
#3 0xb695a75e in QQuickPixmapReader::processJobs (this=0xa8805fc8) at util/qquickpixmapcache.cpp:529
        runningJob = 0x9ffa5ba0
        url = {d = 0xa7bccd10}
        requestSize = {wd = 198, ht = 198}
        locker = {val = 2826985440}
#4 0xb695a7b4 in QQuickPixmapReaderThreadObject::event (this=<optimized out>, e=<optimized out>)
    at util/qquickpixmapcache.cpp:482
No locals.
#5 0xb6726226 in QCoreApplication::notify (this=<optimized out>, receiver=<optimized out>,
    event=<optimized out>) at kernel/qcoreapplication.cpp:943
        d = <optimized out>
#6 0xb672600a in QCoreApplication::notifyInternal (this=0xafa00628, receiver=receiver@entry=0xb15031c0,
    event=event@entry=0x9ff73168) at kernel/qcoreapplication.cpp:881
        threadData = 0xa7b9e818
        loopLevelCounter = {threadData = 0xa7b9e818}
        result = false
        cbdata = {0xb15031c0, 0x9ff73168, 0xa7af10bb}
        d = 0xb1507530
#7 0xb6727c6c in sendEvent (event=0x9ff73168, receiver=0xb15031c0) at kernel/qcoreapplication.h:232
No locals.
#8 QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0,
    data=0xa7b9e818) at kernel/qcoreapplication.cpp:1485
        e = 0x9ff73168
        pe = <optimized out>
        r = 0xb1...

It prevents the package (or a dependent one) from functioning correctly at all.

Ok, so i could reproduce it easily when using master but after trying the branches that move the thumbnailing code away from unity8 i can't reproduce it anymore. I'll link the branches for tracking.

This bug was fixed in the package unity8 - 7.85+14.04.20140401.3-0ubuntu1

---------------
unity8 (7.85+14.04.20140401.3-0ubuntu1) trusty; urgency=medium

  [ Michał Sawicz ]
  * Bump version to ensure incompatibility with previous Unity.Application
    implementations.
  * We'll only have the unity-mir and mock Ubuntu.Application plugins
    now, no need for mangling the import paths.

  [ Michal Hruby ]
  * Remove the albumart image provider. (LP: #1262711)
  * Don't reset search string after 2 seconds. (LP: #1297246)

  [ James Henstridge ]
  * Remove the albumart image provider. (LP: #1262711)

  [ Albert Astals ]
  * Carousel: Add test to make sure we only create the needed delegates
    and not more
  * LVWPH: Remove processEvents() call from updatePolish() It causes
    some reentrancy issues and in some times you end up in polishItems()
    with items that have been deleted because you called processEvents()
    This means i need a small tweak in itemGeometryChanged to not
    reposition items if we are inside a setContentHeight call and two
    small tweaks to tests since now things happen in a different order
    and numbers are different (though equivalent) (LP: #1297240)
  * Card.qml binding loops are gone. hooray \o/ Also made the aspect
    properties readonly

  [ Mirco Müller ]
  * A potential fix for "Cannot read property 'state' of null"-failure
    on Jenkins with the VisualSnapDecisionsQueue QML-test of
    notifications.

  [ Michael Terry ]
  * Pass user's preference for auto-brightness on to powerd. (LP:
    #1273174)

  [ Michael Zanetti ]
  * Registers a dummy QObject as QTestRootObject in uqmlscene in order
    to fix make trySomething with Qt 5.2.
 -- Ubuntu daily release <email address hidden> Tue, 01 Apr 2014 22:56:52 +0000