From kde-core-devel  Tue Jan 18 14:05:46 2005
From: Waldo Bastian <bastian () suse ! com>
Date: Tue, 18 Jan 2005 14:05:46 +0000
To: kde-core-devel
Subject: Re: serious kfind and famd problems, help needed
Message-Id: <200501181505.46958.bastian () suse ! com>
X-MARC-Message: https://marc.info/?l=kde-core-devel&m=110605715100583

On Monday 17 January 2005 19:33, Josef Weidendorfer wrote:
> On Sunday 09 January 2005 14:34, Alexander Neundorf wrote:
> > Hi,
> >
> > famd seems to cause serious problems with kfind:
> > http://bugs.kde.org/show_bug.cgi?id=68220
> > http://bugs.kde.org/show_bug.cgi?id=77846
> > http://bugs.kde.org/show_bug.cgi?id=77854
> > http://bugs.kde.org/show_bug.cgi?id=79512
> > http://bugs.kde.org/show_bug.cgi?id=85802
> >
> > I don't have fam installed so I can't reproduce and fix it.
> > Could somebody who has fam installed please have a look ?
> >
> > Thanks
> > Alex
>
> Hi,
>
> the following code in kfinddlg.cpp looks quite suspicious:
> =============================
> ...
>   //Getting a list of all subdirs
>   if(tabWidget->isSearchRecursive() && (dirwatch->internalMethod() ==
> KDirWatch::FAM))
>   {
>     QStringList subdirs=getAllSubdirs(query->url().path());
>     for(QStringList::Iterator it = subdirs.begin(); it != subdirs.end();
> ++it) dirwatch->addDir(*it,true);
>   }
> ...
> ================================
> Why does anybody want to add dirWatches for *all* directories searched?
> Even more strange: Why is this only enabled when FAM is used?
>
> But if you look at the code of getAllSubdirs(), you partly will kow why
> this can lock up:
> ===================================
> ...
>   for(QStringList::Iterator it = dirs.begin(); it != dirs.end(); ++it)
>   {
>     if((*it==".")||(*it==".."))
>       continue;
>     subdirs.append(d.path()+"/"+*it);
>     subdirs+=getAllSubdirs(d.path()+"/"+*it);
>   }
> ...
> =====================================
> If the start dir is "/", this will freeze kfind GUI while scanning your
> whole harddisk. Such potentially long lasting code parts should be done in
> chunks, triggered by timer events from the main loop (or in another
> thread).
>
> But it gets better: Doing a strace on kfind, I get
> ...
> lstat64
> ("/home/weidendo/DRI/drm/linux/linux/linux/linux/linux/linux/linux/linux/li
>nux/linux/mach64.mod.c", {st_mode=S_IFREG|0644, st_size=559, ...}) = 0
> .....
>
> Why is linux appearing 10x in this path ??!?
> Looking into DRI/drm, I see that linux is a symlink to ".". So obviously
> getAllSubdirs() deadlocks with recursive symlinks.
>
> And this really has *nothing* to do with fam at all, but unfortunately for
> fam, this buggy getAllSubdirs() is only called when fam is used, triggering
> this deadlock.
>
> I can understand that fam looks strange to some people, but this almost
> looks like somebody wanting to kill good old fam's fame by introducing bugs
> which look like fam being the culprit. Sorry, couldn't resist ;-)
>
> Good luck fixing this,
> Josef
>
> PS: I simply would remove the above cited if-body.

Yes, those are good points and that would probably help a lot. I'm not sure 
that it explains http://bugs.kde.org/show_bug.cgi?id=77854 though, that very 
much suggests a FAM deadlock. (Disabling the above if-body would get rid of 
that as well of course)

Cheers,
Waldo
-- 
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