Application: digikam (2.8.0)
KDE Platform Version: 4.9.2 (Compiled from sources)
Qt Version: 4.8.2
Operating System: Linux 3.2.0-30-generic x86_64
Distribution: Ubuntu 12.04.1 LTS

-- Information about the crash:
- What I was doing when the application crashed:

DigiKam is crashing, as long as it is on the way to do somes services as
- searching for ne pics (usually quick and no crash)
- creating thumbnails (lasting hours to days) :-(
- rebuild fingerprints (takes hours..., usually , DK crashes her...) :-(

Servicing feels like endless walking in circles... never comes to an end without crashes... endless attempts


Axel

The crash can be reproduced some of the time.

-- Backtrace:
Application: digiKam (digikam), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
[Current thread is 1 (Thread 0x7f1d53119a00 (LWP 2476))]

Thread 10 (Thread 0x7f1d2ee4c700 (LWP 2609)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
#1  0x00007f1d4d58258b in wait (time=18446744073709551615, this=0xd7d3b0) at thread/qwaitcondition_unix.cpp:86
#2  QWaitCondition::wait (this=<optimized out>, mutex=0xd7d2a8, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:158
#3  0x00000000005d6a30 in Digikam::ScanController::run (this=0xd7d040) at /build/buildd/digikam-2.8.0/core/digikam/database/scancontroller.cpp:698
#4  0x00007f1d4d58207b in QThreadPrivate::start (arg=0xd7d040) at thread/qthread_unix.cpp:307
#5  0x00007f1d480c0e9a in start_thread (arg=0x7f1d2ee4c700) at pthread_create.c:308
#6  0x00007f1d4c7addbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#7  0x0000000000000000 in ?? ()

Thread 9 (Thread 0x7f1d2e64b700 (LWP 2610)):
#0  0x00007f1d4c7a2403 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007f1d45d10036 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f1d45d10164 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f1d4d6b0906 in QEventDispatcherGlib::processEvents (this=0x7f1d200008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#4  0x00007f1d4d67fe42 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f1d4d680097 in QEventLoop::exec (this=0x7f1d2e64ab50, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007f1d4d57f057 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#7  0x00007f1d4d65fb4f in QInotifyFileSystemWatcherEngine::run (this=0xd9a7c0) at io/qfilesystemwatcher_inotify.cpp:248
#8  0x00007f1d4d58207b in QThreadPrivate::start (arg=0xd9a7c0) at thread/qthread_unix.cpp:307
#9  0x00007f1d480c0e9a in start_thread (arg=0x7f1d2e64b700) at pthread_create.c:308
#10 0x00007f1d4c7addbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#11 0x0000000000000000 in ?? ()

Thread 8 (Thread 0x7f1d2de4a700 (LWP 2880)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
#1  0x00007f1d4d58258b in wait (time=18446744073709551615, this=0x10eb960) at thread/qwaitcondition_unix.cpp:86
#2  QWaitCondition::wait (this=<optimized out>, mutex=0xd2b848, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:158
#3  0x00007f1d509a3a11 in Digikam::ParkingThread::run (this=0xd2b830) at /build/buildd/digikam-2.8.0/core/libs/threads/threadmanager.cpp:119
#4  0x00007f1d4d58207b in QThreadPrivate::start (arg=0xd2b830) at thread/qthread_unix.cpp:307
#5  0x00007f1d480c0e9a in start_thread (arg=0x7f1d2de4a700) at pthread_create.c:308
#6  0x00007f1d4c7addbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#7  0x0000000000000000 in ?? ()

Thread 7 (Thread 0x7f1d1c152700 (LWP 2885)):
#0  0x00007f1d4c7a2403 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007f1d45d10036 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f1d45d10164 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f1d4d6b0906 in QEventDispatcherGlib::processEvents (this=0x7f1d140008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#4  0x00007f1d4d67fe42 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f1d4d680097 in QEventLoop::exec (this=0x7f1d1c151b50, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007f1d4d57f057 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#7  0x00007f1d4d65fb4f in QInotifyFileSystemWatcherEngine::run (this=0x1613d10) at io/qfilesystemwatcher_inotify.cpp:248
#8  0x00007f1d4d58207b in QThreadPrivate::start (arg=0x1613d10) at thread/qthread_unix.cpp:307
#9  0x00007f1d480c0e9a in start_thread (arg=0x7f1d1c152700) at pthread_create.c:308
#10 0x00007f1d4c7addbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#11 0x0000000000000000 in ?? ()

Thread 6 (Thread 0x7f1d0e8e2700 (LWP 4493)):
#0  0x00007f1d4c7a2403 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007f1d45d10036 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f1d45d10164 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f1d4d6b0906 in QEventDispatcherGlib::processEvents (this=0x7f1d0409d650, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#4  0x00007f1d4d67fe42 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f1d4d680097 in QEventLoop::exec (this=0x7f1d0e8e1b20, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007f1d509a308e in Digikam::WorkerObjectRunnable::run (this=0x6e3bf4b0) at /build/buildd/digikam-2.8.0/core/libs/threads/threadmanager.cpp:196
#7  0x00007f1d4d5755a2 in QThreadPoolThread::run (this=0xe2b45a0) at concurrent/qthreadpool.cpp:107
#8  0x00007f1d4d58207b in QThreadPrivate::start (arg=0xe2b45a0) at thread/qthread_unix.cpp:307
#9  0x00007f1d480c0e9a in start_thread (arg=0x7f1d0e8e2700) at pthread_create.c:308
#10 0x00007f1d4c7addbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#11 0x0000000000000000 in ?? ()

Thread 5 (Thread 0x7f1d0f0e3700 (LWP 4495)):
[KCrash Handler]
#6  0x00007f1d507c1933 in Digikam::TIFFLoader::load (this=0x7f1d0f0e1b30, filePath=..., observer=0x6fa67ad0) at /build/buildd/digikam-2.8.0/core/libs/dimg/loaders/tiffloader.cpp:638
#7  0x00007f1d5079cacd in Digikam::DImg::load (this=0x7f1d0f0e22a0, filePath=..., loadFlagsInt=13, observer=0x6fa67ad0, rawDecodingSettings=...) at /build/buildd/digikam-2.8.0/core/libs/dimg/dimg.cpp:451
#8  0x00007f1d5079e18e in Digikam::DImg::load (this=0x7f1d0f0e22a0, filePath=..., loadMetadata=<optimized out>, loadICCData=<optimized out>, loadUniqueHash=<optimized out>, loadImageHistory=<optimized out>, observer=0x6fa67ad0, rawDecodingSettings=...) at /build/buildd/digikam-2.8.0/core/libs/dimg/dimg.cpp:406
#9  0x00007f1d50982488 in Digikam::ThumbnailCreator::loadWithDImg (this=0x14d74b0, path=..., profile=0x7f1d0f0e2460) at /build/buildd/digikam-2.8.0/core/libs/threadimageio/thumbnailcreator.cpp:561
#10 0x00007f1d50982fcb in Digikam::ThumbnailCreator::createThumbnail (this=0x14d74b0, info=..., detailRect=..., isFace=false) at /build/buildd/digikam-2.8.0/core/libs/threadimageio/thumbnailcreator.cpp:490
#11 0x00007f1d50983630 in Digikam::ThumbnailCreator::load (this=0x14d74b0, path=..., rect=..., pregenerate=true) at /build/buildd/digikam-2.8.0/core/libs/threadimageio/thumbnailcreator.cpp:260
#12 0x00007f1d50984a2d in Digikam::ThumbnailCreator::pregenerate (this=<optimized out>, path=...) at /build/buildd/digikam-2.8.0/core/libs/threadimageio/thumbnailcreator.cpp:183
#13 0x00007f1d50993120 in Digikam::ThumbnailLoadingTask::execute (this=0x6fa67ac0) at /build/buildd/digikam-2.8.0/core/libs/threadimageio/thumbnailtask.cpp:80
#14 0x00007f1d50962b5e in Digikam::LoadSaveThread::run (this=0x14da370) at /build/buildd/digikam-2.8.0/core/libs/threadimageio/loadsavethread.cpp:136
#15 0x00007f1d509a532e in Digikam::DynamicThread::DynamicThreadPriv::run (this=0x160fe40) at /build/buildd/digikam-2.8.0/core/libs/threads/dynamicthread.cpp:186
#16 0x00007f1d4d5755a2 in QThreadPoolThread::run (this=0x6e4005d0) at concurrent/qthreadpool.cpp:107
#17 0x00007f1d4d58207b in QThreadPrivate::start (arg=0x6e4005d0) at thread/qthread_unix.cpp:307
#18 0x00007f1d480c0e9a in start_thread (arg=0x7f1d0f0e3700) at pthread_create.c:308
#19 0x00007f1d4c7addbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#20 0x0000000000000000 in ?? ()

Thread 4 (Thread 0x7f1d0f8e4700 (LWP 4496)):
#0  0x00007f1d48a433d6 in ?? () from /usr/lib/x86_64-linux-gnu/libgomp.so.1
#1  0x00007f1d48a41efe in ?? () from /usr/lib/x86_64-linux-gnu/libgomp.so.1
#2  0x00007f1d480c0e9a in start_thread (arg=0x7f1d0f8e4700) at pthread_create.c:308
#3  0x00007f1d4c7addbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#4  0x0000000000000000 in ?? ()

Thread 3 (Thread 0x7f1d0e0e1700 (LWP 4497)):
#0  0x00007f1d48a433d6 in ?? () from /usr/lib/x86_64-linux-gnu/libgomp.so.1
#1  0x00007f1d48a41efe in ?? () from /usr/lib/x86_64-linux-gnu/libgomp.so.1
#2  0x00007f1d480c0e9a in start_thread (arg=0x7f1d0e0e1700) at pthread_create.c:308
#3  0x00007f1d4c7addbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#4  0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7f1d0d8e0700 (LWP 4498)):
#0  0x00007f1d48a433d6 in ?? () from /usr/lib/x86_64-linux-gnu/libgomp.so.1
#1  0x00007f1d48a41efe in ?? () from /usr/lib/x86_64-linux-gnu/libgomp.so.1
#2  0x00007f1d480c0e9a in start_thread (arg=0x7f1d0d8e0700) at pthread_create.c:308
#3  0x00007f1d4c7addbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#4  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f1d53119a00 (LWP 2476)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
#1  0x00007f1d4d58258b in wait (time=18446744073709551615, this=0xf68290) at thread/qwaitcondition_unix.cpp:86
#2  QWaitCondition::wait (this=<optimized out>, mutex=0xd19938, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:158
#3  0x00007f1d509a3e00 in Digikam::WorkerObject::wait (this=0xf6e850) at /build/buildd/digikam-2.8.0/core/libs/threads/workerobject.cpp:95
#4  0x00007f1d509a47e4 in Digikam::WorkerObject::~WorkerObject (this=0xf6e850, __in_chrg=<optimized out>) at /build/buildd/digikam-2.8.0/core/libs/threads/workerobject.cpp:75
#5  0x00000000005dd4c0 in ~DIOPriv (this=0xf6e850, __in_chrg=<optimized out>) at /build/buildd/digikam-2.8.0/obj-x86_64-linux-gnu/core/digikam/../../../core/digikam/database/dio_p.h:37
#6  Digikam::DIO::DIOPriv::~DIOPriv (this=0xf6e850, __in_chrg=<optimized out>) at /build/buildd/digikam-2.8.0/obj-x86_64-linux-gnu/core/digikam/../../../core/digikam/database/dio_p.h:37
#7  0x00000000005da2be in Digikam::DIO::~DIO (this=0x10f4fb0, __in_chrg=<optimized out>) at /build/buildd/digikam-2.8.0/core/digikam/database/dio.cpp:253
#8  0x00000000005da337 in ~DIOCreator (this=0x10f4fb0, __in_chrg=<optimized out>) at /build/buildd/digikam-2.8.0/core/digikam/database/dio.cpp:230
#9  destroy () at /build/buildd/digikam-2.8.0/core/digikam/database/dio.cpp:237
#10 0x00007f1d4c6f5921 in __run_exit_handlers (status=1, listp=0x7f1d4ca72688, run_list_atexit=true) at exit.c:78
#11 0x00007f1d4c6f59a5 in __GI_exit (status=<optimized out>) at exit.c:100
#12 0x00007f1d4e0e7508 in qt_xio_errhandler () at kernel/qapplication_x11.cpp:780
#13 0x00007f1d4edb4a18 in KApplication::xioErrhandler (this=0x7fff87edb830, dpy=0xcd2540) at ../../kdeui/kernel/kapplication.cpp:419
#14 0x00007f1d4acb641e in _XIOError () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#15 0x00007f1d4acb438b in _XReply () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#16 0x00007f1d4ac9a381 in XGetSelectionOwner () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#17 0x00007f1d32712548 in Oxygen::StyleHelper::compositingActive (this=<optimized out>) at ../../../kstyles/oxygen/oxygenstylehelper.cpp:653
#18 0x00007f1d326f64d6 in hasAlphaChannel (widget=<optimized out>, this=<optimized out>) at ../../../kstyles/oxygen/oxygenstylehelper.h:274
#19 Oxygen::Style::styleHint (this=0xf98e20, hint=<optimized out>, option=0x7fff87ed9ed0, widget=<optimized out>, returnData=0x7fff87ed9f10) at ../../../kstyles/oxygen/oxygenstyle.cpp:821
#20 0x00007f1d509b9dd5 in Digikam::DItemToolTip::resizeEvent (this=0xf8d690, e=0x7fff87eda6e0) at /build/buildd/digikam-2.8.0/core/libs/widgets/common/ditemtooltip.cpp:345
#21 0x00007f1d4e0cbf9a in QWidget::event (this=0xf8d690, event=0x7fff87eda6e0) at kernel/qwidget.cpp:8525
#22 0x00007f1d4e48c836 in QFrame::event (this=0xf8d690, e=0x7fff87eda6e0) at widgets/qframe.cpp:557
#23 0x00007f1d4e07b7b4 in notify_helper (e=0x7fff87eda6e0, receiver=0xf8d690, this=0xcc55d0) at kernel/qapplication.cpp:4556
#24 QApplicationPrivate::notify_helper (this=0xcc55d0, receiver=0xf8d690, e=0x7fff87eda6e0) at kernel/qapplication.cpp:4528
#25 0x00007f1d4e080583 in QApplication::notify (this=0x7fff87edb830, receiver=0xf8d690, e=0x7fff87eda6e0) at kernel/qapplication.cpp:4417
#26 0x00007f1d4edb6756 in KApplication::notify (this=0x7fff87edb830, receiver=0xf8d690, event=0x7fff87eda6e0) at ../../kdeui/kernel/kapplication.cpp:311
#27 0x00007f1d4d68130c in QCoreApplication::notifyInternal (this=0x7fff87edb830, receiver=0xf8d690, event=0x7fff87eda6e0) at kernel/qcoreapplication.cpp:915
#28 0x00007f1d4e0c6a55 in sendEvent (event=0x7fff87eda6e0, receiver=0xf8d690) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#29 QWidgetPrivate::sendPendingMoveAndResizeEvents (this=0xd525e0, recursive=false, disableUpdates=<optimized out>) at kernel/qwidget.cpp:7441
#30 0x00007f1d4e0ce551 in QWidgetPrivate::show_helper (this=<optimized out>) at kernel/qwidget.cpp:7492
#31 0x00007f1d4e0ce972 in QWidget::setVisible (this=0xf8d690, visible=<optimized out>) at kernel/qwidget.cpp:7773
#32 0x00007f1d509fe596 in show (this=0xf8d690) at /usr/include/qt4/QtGui/qwidget.h:494
#33 Digikam::ItemViewToolTip::show (this=0xf8d690, option=..., index=...) at /build/buildd/digikam-2.8.0/core/libs/widgets/itemview/itemviewtooltip.cpp:100
#34 0x00007f1d509f123f in Digikam::DCategorizedView::showToolTip (this=0xd23a20, index=..., option=..., he=<optimized out>) at /build/buildd/digikam-2.8.0/core/libs/widgets/itemview/dcategorizedview.cpp:734
#35 0x00007f1d509f2897 in Digikam::DCategorizedView::viewportEvent (this=0xd23a20, event=0x7fff87edae90) at /build/buildd/digikam-2.8.0/core/libs/widgets/itemview/dcategorizedview.cpp:940
#36 0x00007f1d4d681498 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=<optimized out>, receiver=0xd24050, event=0x7fff87edae90) at kernel/qcoreapplication.cpp:1025
#37 0x00007f1d4e07b77f in notify_helper (e=0x7fff87edae90, receiver=0xd24050, this=0xcc55d0) at kernel/qapplication.cpp:4552
#38 QApplicationPrivate::notify_helper (this=0xcc55d0, receiver=0xd24050, e=0x7fff87edae90) at kernel/qapplication.cpp:4528
#39 0x00007f1d4e08084f in QApplication::notify (this=<optimized out>, receiver=0xd24050, e=0x7fff87edae90) at kernel/qapplication.cpp:4238
#40 0x00007f1d4edb6756 in KApplication::notify (this=0x7fff87edb830, receiver=0xd24050, event=0x7fff87edae90) at ../../kdeui/kernel/kapplication.cpp:311
#41 0x00007f1d4d68130c in QCoreApplication::notifyInternal (this=0x7fff87edb830, receiver=0xd24050, event=0x7fff87edae90) at kernel/qcoreapplication.cpp:915
#42 0x00007f1d4e07f91e in sendEvent (event=0x7fff87edae90, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#43 QApplication::event (this=0x7fff87edb830, e=0x7fff87edb450) at kernel/qapplication.cpp:2529
#44 0x00007f1d4e07b7b4 in notify_helper (e=0x7fff87edb450, receiver=0x7fff87edb830, this=0xcc55d0) at kernel/qapplication.cpp:4556
#45 QApplicationPrivate::notify_helper (this=0xcc55d0, receiver=0x7fff87edb830, e=0x7fff87edb450) at kernel/qapplication.cpp:4528
#46 0x00007f1d4e080583 in QApplication::notify (this=0x7fff87edb830, receiver=0x7fff87edb830, e=0x7fff87edb450) at kernel/qapplication.cpp:4417
#47 0x00007f1d4edb6756 in KApplication::notify (this=0x7fff87edb830, receiver=0x7fff87edb830, event=0x7fff87edb450) at ../../kdeui/kernel/kapplication.cpp:311
#48 0x00007f1d4d68130c in QCoreApplication::notifyInternal (this=0x7fff87edb830, receiver=0x7fff87edb830, event=0x7fff87edb450) at kernel/qcoreapplication.cpp:915
#49 0x00007f1d4d6b26d2 in sendEvent (event=0x7fff87edb450, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#50 QTimerInfoList::activateTimers (this=0xcc6b60) at kernel/qeventdispatcher_unix.cpp:611
#51 0x00007f1d4d6b00ed in timerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:186
#52 timerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:180
#53 0x00007f1d45d0fd53 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#54 0x00007f1d45d100a0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#55 0x00007f1d45d10164 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#56 0x00007f1d4d6b089f in QEventDispatcherGlib::processEvents (this=0xc60af0, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#57 0x00007f1d4e123cde in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#58 0x00007f1d4d67fe42 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#59 0x00007f1d4d680097 in QEventLoop::exec (this=0x7fff87edb6b0, flags=...) at kernel/qeventloop.cpp:204
#60 0x00007f1d4d6853e7 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1187
#61 0x000000000048f63b in main (argc=3, argv=<optimized out>) at /build/buildd/digikam-2.8.0/core/digikam/main/main.cpp:232

Possible duplicates by query: bug 307602, bug 307275, bug 307119, bug 307013, bug 306492.

Reported using DrKonqi