kded4 lockup (which makes the desktop unusable so this is important)
ahartmetz at gmail.com
Thu May 8 17:08:42 BST 2008
2008/5/8 Andreas Hartmetz <ahartmetz at gmail.com>:
> Hi all,
> yesterday I finally got around to doing some research into the
> infamous problem that sometimes when you alt-tab the alt key would
> "stick" and effectively make the desktop useless.
> It seems to be caused by a completely stuck kded4. It is stuck in the
> dirwatcher part, apparently.
> The following output from gdb and .xsession-errors is probably
> information enough information to find the bug for somebody who knows
> the code involved (David maybe?).
> Note that after I killed kded4 when I had extracted enough information
> out of it the keyboard started to work normally again and I could
> continue to use the desktop (I did the debugging from a different
> machine over ssh).
> I think we should also consider ways to make kded4 less brittle
> because it's quite important. Resistance against crashes in modules
> would be cool but also somewhat heavyweight so maybe one thread per
> module would help? This is assuming that QDBus can work sensibly in a
> multithreaded environment, only blocking one thread waiting for one
> Anyway, here is the debug output etc.
> #0 0xb7fd3410 in __kernel_vsyscall ()
> #1 0xb75ae8f3 in __write_nocancel () from
> #2 0xb6b58dca in Client::writeToServer () from /usr/lib/libfam.so.0
> #3 0xb6b5b9ef in ?? () from /usr/lib/libfam.so.0
Did you know...
FAM has been the default backend of KDirWatch for years but it was not
actually used due to a typo in an #ifdef (!!!) that was fixed four
As a workaround for that nasty lockup I have modified KDirWatch to use
inotify as the default backend again, this time in a more obvious
--- kdirwatch.cpp (Revision 805216)
+++ kdirwatch.cpp (Arbeitskopie)
@@ -124,7 +124,7 @@
m_nfsPollInterval = config.readEntry("NFSPollInterval", 5000);
m_PollInterval = config.readEntry("PollInterval", 500);
- QString method = config.readEntry("PreferredMethod", "Fam");
+ QString method = config.readEntry("PreferredMethod", "inotify");
if (method == "Fam")
m_preferredMethod = Fam;
I can't believe it.
Update your kdelibs now.
I believe that we should still look for ways to make kded (way) more
robust. Strange things will happen everytime one module takes down or,
worse, locks up kded.
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