Bug 327073

Summary:	Random freezes
Product:	[Applications] digikam	Reporter:	Alphazo <alphazo>
Component:	Portability-Runtime	Assignee:	Digikam Developers <digikam-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	crash	CC:	caulier.gilles, fx.payet
Priority:	NOR
Version:	3.5.0
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed In:	7.6.0
Sentry Crash Report:

Description Alphazo 2013-11-03 10:30:22 UTC

I just installed ArchLinux on a brand new Intel i7 4770S (Haswell). I have the exact package versions on the new and old machines but when performing simple operations such a renaming or moving files, DigiKam would just freeze.

In the meantime I also experienced severe issues on Kdenlive when simply disabling an effect.
You can see my bug report on Kdenlive bug tracker here: http://www.kdenlive.org/mantis/view.php?id=3186

I then looked at the trace and found this stuff about lock elision that seems very (hardware) specific to Haswell CPU. http://lwn.net/Articles/534758/

I looked at the ArchLinux PKGBUILD for the current pre-compiled glibc 2.18-9 and it has the "--enable-lock-elision" switch. I then recompiled glibc 2.18-9 but without support for enable-lock-elision and problem was gone.

I haven't had a chance to play with Digikam again but this might have fixed my instabilities as well. Is there any lock elision related code in Digikam or is the lock elision implementation in current glibc buggy when ran on Haswell processors ? 

Reproducible: Sometimes

Steps to Reproduce:
- Moving a small number of files to a different album
- Renaming some files
Actual Results:  
Freeze. I have to to force close the application.

Comment 1 caulier.gilles 2013-11-05 21:15:26 UTC

It's probably a glibc issue on your computer...

Gilles Caulier

Comment 2 caulier.gilles 2013-11-25 12:24:02 UTC

It's not a digiKam relevant issue, but more an in-deep  system problem. 

Please fix, update or change your host system and try again...

Gilles Caulier

Comment 3 François-Xavier Payet 2014-05-12 10:02:07 UTC

I'm not sure it's not a Digikam issues, as KDEEnLive had the same (apparent) same problem, and did solve it on their end.

Are you sure the issue can't be related to Digikam?

Comment 4 caulier.gilles 2014-05-12 11:11:05 UTC

>"and did solve it on their end."

How did solve it exactly ? There is a report to KDenlive bugzilla ?

Gilles Caulier

Comment 5 Alphazo 2014-05-12 12:12:01 UTC

The bug report on Kdenlive found in the opening post gives a link to the following fix:

http://quickgit.kde.org/?p=kdenlive.git&a=commitdiff&h=d049b327afc02b499266b5c895b13e438490b7c0&o=plain

Once I applied this patch (now included in the latest release) problems were gone. Now I haven't moved a lot of file lately on DigiKam so I cannot comment on DigiKam stability with Haswell CPU.

Comment 6 caulier.gilles 2014-05-12 12:42:07 UTC

The commit from KDenlive sound like a missing mutex to lock about multi-processing rules.

Gilles Caulier