https://bugs.kde.org/show_bug.cgi?id=451059
--- Comment #9 from Amaury Pouly <amaury.po...@gmail.com> --- Hi, I have made progress on this (I think)! By running okular in a debugger and stopping the program when it freezes, I have noticed that almost every time the backtrace is as follows (slightly abbreviated): #0 0x00007ffff6231be5 in __GI___clock_nanosleep (clock_id=clock_id@entry=0, flags=flags@entry=0, req=0x7fffffffd0f0, rem=0x7fffffffd0f0) at ../sysdeps/unix/sysv/linux/clock_nanosleep.c:43 #1 0x00007ffff6236ca3 in __GI___nanosleep (req=<optimized out>, rem=<optimized out>) at ../sysdeps/unix/sysv/linux/nanosleep.c:25 #2 0x00007ffff686ca5d in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #3 0x00007ffff674b01f in QLockFile::tryLock(int) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #4 0x00007ffff79adc59 in KConfigIniBackend::lock (this=0x5555556e12b0) at ./src/core/kconfigini.cpp:632 #5 0x00007ffff7998796 in KConfigPrivate::lockLocal (this=0x5555556e2a90) at ./src/core/kconfig.cpp:123 #6 KConfig::sync (this=0x5555556e2b50) at ./src/core/kconfig.cpp:422 #7 0x00007ffff7c97c0e in KMainWindow::saveAutoSaveSettings (this=<optimized out>) at ./src/kmainwindow.cpp:882 #8 0x00007ffff684c123 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #9 0x00007ffff684ffca in QTimer::timeout(QTimer::QPrivateSignal) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 Recall that I have many (20+) instances of okular running so my theory is now that there might be a lot of contention on the config file lock. This can be easily checked by running (in my case): inotifywait -m -r /home/pamaury/.config/ and observe that okular is *very very frequently* taking a lock okularrc.lock to write okularrc. Actually, this is slightly scary: just switching between virtual desktop will trigger a flurry of creation/deletion of this file. I cannot explain yet *how* this can possibly lock for 10 seconds however. -- You are receiving this mail because: You are the assignee for the bug.