linux-kernel - Re: Kaffeine problem with CFS

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Date:	Wed, 18 Apr 2007 12:04:36 +0200
From:	"Christoph Pfister" <christophpfister@...il.com>
To:	"Ingo Molnar" <mingo@...e.hu>
Cc:	"S.Çağlar Onur" <caglar@...dus.org.tr>,
	linux-kernel@...r.kernel.org,
	"Michael Lothian" <mike@...eburn.co.uk>,
	"Christophe Thommeret" <hftom@...e.fr>,
	"Jurgen Kofler" <kaffeine@....net>,
	"Ulrich Drepper" <drepper@...hat.com>
Subject: Re: Kaffeine problem with CFS

2007/4/18, Christoph Pfister <christophpfister@...il.com>:
> 2007/4/18, Ingo Molnar <mingo@...e.hu>:
> >
> > * Christoph Pfister <christophpfister@...il.com> wrote:
> >
> > > >which thread would be the most interesting to you - 9324?
> > >
> > > The thread which should wake the main thread - but hmm ... 9303 seems
> > > to be rather dead-locked than doing pthread_cond_timedwait() ?
> >
> > ok, here it is, 9303 with better symbol names:
> >
> > #0  0xffffe410 in __kernel_vsyscall ()
> > #1  0x4a2538ce in __lll_mutex_lock_wait () from /lib/libpthread.so.0
> > #2  0x4a24f71c in _L_mutex_lock_79 () from /lib/libpthread.so.0
> > #3  0x4a24f24d in pthread_mutex_lock () from /lib/libpthread.so.0
> > #4  0xb79f64f9 in xine_play () from /usr/lib/libxine.so.1
> > #5  0xb7a9b0fb in KXineWidget::slotSeekToPosition ()
> >    from /usr/lib/kde3/libxinepart.so
> > #6  0xb7a9b3bc in KXineWidget::wheelEvent () from /usr/lib/kde3/libxinepart.so
> > #7  0x4b5f9150 in QWidget::event () from /usr/lib/qt-3.3/lib/libqt-mt.so.3
> > #8  0x4b55353b in QApplication::internalNotify ()
> >    from /usr/lib/qt-3.3/lib/libqt-mt.so.3
> > #9  0x4b55526e in QApplication::notify ()
> >    from /usr/lib/qt-3.3/lib/libqt-mt.so.3
> > #10 0x4a72065e in KApplication::notify () from /usr/lib/libkdecore.so.4
> > #11 0x4b4dd5de in QETWidget::translateWheelEvent ()
> >    from /usr/lib/qt-3.3/lib/libqt-mt.so.3
> > #12 0x4b4eb41d in QETWidget::translateMouseEvent ()
> >    from /usr/lib/qt-3.3/lib/libqt-mt.so.3
> > #13 0x4b4e9766 in QApplication::x11ProcessEvent ()
> >    from /usr/lib/qt-3.3/lib/libqt-mt.so.3
> > #14 0x4b4fb38b in QEventLoop::processEvents ()
> >    from /usr/lib/qt-3.3/lib/libqt-mt.so.3
> > #15 0x4b56ce30 in QEventLoop::enterLoop ()
> >    from /usr/lib/qt-3.3/lib/libqt-mt.so.3
> > #16 0x4b56cce6 in QEventLoop::exec () from /usr/lib/qt-3.3/lib/libqt-mt.so.3
> > #17 0x4b55317f in QApplication::exec () from /usr/lib/qt-3.3/lib/libqt-mt.so.3
> > #18 0x0806fc1a in QWidget::setUpdatesEnabled ()
> > #19 0x49f9df10 in __libc_start_main () from /lib/libc.so.6
> > #20 0x0806f7e1 in QWidget::setUpdatesEnabled ()
> >
> > does this make more sense to you?
>
> It's nearly impossible for me to find out which mutex is deadlocking.
> There are 4 mutexs locked / released during xine_play (or one of the
> possibly inlined functions) and to be honest I have little idea which
> other thread is also involved in the deadlock (maybe some xine-lib
> junkie could help you more with that).
> It would be great if you could reproduce the same problem with a
> xine-lib which has been compiled with debug support (so you'd get line
> numbers in the back trace - that makes life _a lot_ easier and maybe I
> could identify the problem that way) and the least optimization
> possible ... :-)
>
> >         Ingo

Or I could try playing around a bit with your patchset and trying to
reproduce it over here. Because I already have debug builds for
xine-lib and compiling a new kernel can take place in the background
it wouldn't be much effort for me.

Christoph
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