Are you sure that if you leave it waiting it will never load the file?

I left okular in busy state for 10 min, and it still hasn't opened the file.

Can you share that dvi file? If so could you attach it to the bug?

This is bizarre. Some data:
1. The probability of this occurring increases, if the CPU is very busy, at about 10%, i.e. running 'while true;  do true;  done' in parallel. It also increases when opening files I haven't opened before.
2. Font generation seems to be irrelevant: I deleted the cache of pk files (/var/cache/fonts) to no avail; they aren't recreated and dvi files display fine. Note: I have never seen the "generating font" message I remember from KDE3 times.
3. The dvi file is _not_ opened, while okular is hung, according to lsof.
4. I can reproduce this with:
\documentclass{article}

\begin{document}
testing
\end{document}
in a tex file.

This is a more complete backtrace from okular 4.4.2:

Application: Okular (okular), signal: Segmentation fault
[Current thread is 1 (Thread 0xb54c0700 (LWP 26425))]

Thread 2 (Thread 0xb1aceb70 (LWP 26426)):
#0  0xffffe424 in __kernel_vsyscall ()
#1  0xb5f381a1 in select () from /lib/libc.so.6
#2  0xb6c79388 in QProcessManager::run (this=0xb6db6888) at io/qprocess_unix.cpp:245
#3  0xb6b9e67f in QThreadPrivate::start (arg=0xb6db6888) at thread/qthread_unix.cpp:248
#4  0xb5a6d945 in start_thread () from /lib/libpthread.so.0
#5  0xb5f3f62e in clone () from /lib/libc.so.6

Thread 1 (Thread 0xb54c0700 (LWP 26425)):
[KCrash Handler]
#6  Okular::Document::closeDocument (this=0x81df548) at /usr/src/debug/kdegraphics-4.4.2/okular/core/document.cpp:1810
#7  0xb38e8a68 in Okular::Part::closeUrl (this=0x81ce618) at /usr/src/debug/kdegraphics-4.4.2/okular/part.cpp:1105
#8  0xb38e8ee0 in Okular::Part::~Part (this=0x81ce618, __in_chrg=<value optimized out>, __vtt_parm=<value optimized out>) at /usr/src/debug/kdegraphics-4.4.2/okular/part.cpp:630
#9  0xb38e8f62 in Okular::Part::~Part (this=0x81ce618, __in_chrg=<value optimized out>, __vtt_parm=<value optimized out>) at /usr/src/debug/kdegraphics-4.4.2/okular/part.cpp:654
#10 0x08050279 in Shell::~Shell (this=0x81bc218, __in_chrg=<value optimized out>, __vtt_parm=<value optimized out>) at /usr/src/debug/kdegraphics-4.4.2/okular/shell/shell.cpp:119
#11 0x08050350 in Shell::~Shell (this=0x81bc218, __in_chrg=<value optimized out>, __vtt_parm=<value optimized out>) at /usr/src/debug/kdegraphics-4.4.2/okular/shell/shell.cpp:122
#12 0xb6cab2d3 in qDeleteInEventHandler (o=0x81bc218) at kernel/qobject.cpp:3998
#13 0xb6cac7b8 in QObject::event (this=0x81bc218, e=0x8605880) at kernel/qobject.cpp:1231
#14 0xb624d06c in QWidget::event (this=0x81bc218, event=0x8605880) at kernel/qwidget.cpp:8455
#15 0xb666679c in QMainWindow::event (this=0x81bc218, event=0x8605880) at widgets/qmainwindow.cpp:1433
#16 0xb724fdf4 in KMainWindow::event(QEvent*) () from /usr/lib/libkdeui.so.5
#17 0xb7250092 in KXmlGuiWindow::event(QEvent*) () from /usr/lib/libkdeui.so.5
#18 0xb61f4644 in QApplicationPrivate::notify_helper (this=0x80713f8, receiver=0x81bc218, e=0x8605880) at kernel/qapplication.cpp:4300
#19 0xb61f8ad4 in QApplication::notify (this=0x81bc218, receiver=0x81bc218, e=0x8605880) at kernel/qapplication.cpp:4265
#20 0xb71b3c51 in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#21 0xb6c9998e in QCoreApplication::notifyInternal (this=0xbff666f0, receiver=0x81bc218, event=0x8605880) at kernel/qcoreapplication.cpp:704
#22 0xb6c9d4c8 in sendEvent (event=<value optimized out>, receiver=<value optimized out>) at kernel/qcoreapplication.h:215
#23 QCoreApplicationPrivate::sendPostedEvents (event=<value optimized out>, receiver=<value optimized out>) at kernel/qcoreapplication.cpp:1345
#24 0xb6cc8bb3 in QEventDispatcherUNIX::processEvents (this=0x805d600, flags=...) at kernel/qeventdispatcher_unix.cpp:906
#25 0xb62a4f5a in QEventDispatcherX11::processEvents (this=0x805d600, flags=...) at kernel/qeventdispatcher_x11.cpp:152
#26 0xb6c9d8f3 in QCoreApplication::processEvents (flags=...) at kernel/qcoreapplication.cpp:896
#27 0xb1b0d8e3 in fontPool::locateFonts (this=0x856d1a8, makePK=false, locateTFMonly=false, virtualFontsFound=0xbff6565f) at /usr/src/debug/kdegraphics-4.4.2/okular/generators/dvi/fontpool.cpp:322
#28 0xb1b0e579 in fontPool::locateFonts (this=0x856d1a8) at /usr/src/debug/kdegraphics-4.4.2/okular/generators/dvi/fontpool.cpp:205
#29 0xb1ae2d18 in dviRenderer::setFile (this=0x856d188, fname=..., base=...) at /usr/src/debug/kdegraphics-4.4.2/okular/generators/dvi/dviRenderer.cpp:524
#30 0xb1add90a in DviGenerator::loadDocument (this=0x856be10, fileName=..., pagesVector=...) at /usr/src/debug/kdegraphics-4.4.2/okular/generators/dvi/generator_dvi.cpp:113
#31 0xb37ff908 in Okular::DocumentPrivate::openDocumentInternal (this=0x81fa928, offer=..., isstdin=false, docFile=..., filedata=...) at /usr/src/debug/kdegraphics-4.4.2/okular/core/document.cpp:644
#32 0xb38089ca in Okular::Document::openDocument (this=0x81df548, docFile=..., url=..., _mime=...) at /usr/src/debug/kdegraphics-4.4.2/okular/core/document.cpp:1642
#33 0xb38f2b01 in Okular::Part::openFile (this=0x81ce618) at /usr/src/debug/kdegraphics-4.4.2/okular/part.cpp:930
#34 0xb7704f50 in KParts::ReadOnlyPart::openUrl(KUrl const&) () from /usr/lib/libkparts.so.4
#35 0xb38e23de in Okular::Part::openUrl (this=0x81ce618, _url=...) at /usr/src/debug/kdegraphics-4.4.2/okular/part.cpp:1049
#36 0x0804f884 in Shell::openUrl (this=0x81bc218, url=...) at /usr/src/debug/kdegraphics-4.4.2/okular/shell/shell.cpp:130
#37 0x0804f9a6 in Shell::delayedOpen (this=0x81bc218) at /usr/src/debug/kdegraphics-4.4.2/okular/shell/shell.cpp:113
#38 0x0805130c in Shell::qt_metacall (this=0x81bc218, _c=InvokeMetaMethod, _id=<value optimized out>, _a=0xbff65e4c) at /usr/src/debug/kdegraphics-4.4.2/build/okular/shell/shell.moc:94
#39 0xb6c9f9ad in QMetaObject::metacall (object=0x81bc218, cl=InvokeMetaMethod, idx=57, argv=0xbff65e4c) at kernel/qmetaobject.cpp:237
#40 0xb6caf0d3 in QMetaObject::activate (sender=0x8451fd8, m=0xb6db4188, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3293
#41 0xb6cb4605 in QSingleShotTimer::timeout (this=0x8451fd8) at .moc/release-shared/qtimer.moc:82
#42 0xb6cb46bc in QSingleShotTimer::timerEvent (this=0x8451fd8) at kernel/qtimer.cpp:308
#43 0xb6cac5c4 in QObject::event (this=0x8451fd8, e=0xbff66384) at kernel/qobject.cpp:1212
#44 0xb61f4644 in QApplicationPrivate::notify_helper (this=0x80713f8, receiver=0x8451fd8, e=0xbff66384) at kernel/qapplication.cpp:4300
#45 0xb61f8a27 in QApplication::notify (this=0xbff666f0, receiver=0x8451fd8, e=0xbff66384) at kernel/qapplication.cpp:3704
#46 0xb71b3c51 in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#47 0xb6c9998e in QCoreApplication::notifyInternal (this=0xbff666f0, receiver=0x8451fd8, event=0xbff66384) at kernel/qcoreapplication.cpp:704
#48 0xb6cc856e in sendEvent (event=<value optimized out>, receiver=<value optimized out>) at kernel/qcoreapplication.h:215
#49 QTimerInfoList::activateTimers (event=<value optimized out>, receiver=<value optimized out>) at kernel/qeventdispatcher_unix.cpp:617
#50 0xb6cc8c2d in QEventDispatcherUNIX::processEvents (this=0x805d600, flags=...) at kernel/qeventdispatcher_unix.cpp:938
#51 0xb62a4f5a in QEventDispatcherX11::processEvents (this=0x805d600, flags=...) at kernel/qeventdispatcher_x11.cpp:152
#52 0xb6c98c2d in QEventLoop::processEvents (this=0xbff665f4, flags=...) at kernel/qeventloop.cpp:149
#53 0xb6c98e79 in QEventLoop::exec (this=0xbff665f4, flags=...) at kernel/qeventloop.cpp:201
#54 0xb6c9d760 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:981
#55 0xb61f1b84 in QApplication::exec () at kernel/qapplication.cpp:3579
#56 0x0804ef28 in main (argc=0, argv=0x856d708) at /usr/src/debug/kdegraphics-4.4.2/okular/shell/main.cpp:82

This looks similar to bug 211765.

*** This bug has been marked as a duplicate of bug 211765 ***