few days ago I started working with Fedora 14. So far, so good, at least as far as the desktop machine goes (a laptop is another story and Kubuntu runs fine on another desktop). Something has just happened in Fedora which never happened to me before. Kate (an editor) got stuck and its memory (RAM) consumption went up through the roof to over 1.5 GB, so obviously it froze the system for a while. The process needed to be forcibly killed.

Now, it’s not entirely clear what happened there (maybe a program bug), but this is unusual and it looks bad for Fedora or for KDE (or the combination in Fedora 14 KDE spin). What did happen is that SELinux came up with an error implying that it stood in Kate’s way and maybe it’s partly responsible for this type of behaviour. It yielded the following error, implying that it was trying to help when in fact it seemed like it only stood in the way.

Summary:

SELinux is preventing /usr/bin/kate (deleted) “mmap_zero” access on <Unknown>.

Detailed Description:

SELinux denied access requested by kate. The current boolean settings do not
allow this access. If you have not setup kate to require this access this may
signal an intrusion attempt. If you do intend this access you need to change the
booleans on this system to allow the access.

Allowing Access:

Confined processes can be configured to run requiring different access, SELinux
provides booleans to allow you to turn on/off access as needed. The boolean
mmap_low_allowed is set incorrectly.
Boolean Description:
Control the ability to mmap a low area of the address space, as configured by
/proc/sys/kernel/mmap_min_addr.

Fix Command:

# setsebool -P mmap_low_allowed 1

Additional Information:

Source Context unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1
023
Target Context unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1
023
Target Objects None [ memprotect ]
Source kate
Source Path /usr/bin/kate (deleted)
Port &ltUnknown>
Host blueberry
Source RPM Packages
Target RPM Packages
Policy RPM selinux-policy-3.9.7-3.fc14
Selinux Enabled True
Policy Type targeted
Enforcing Mode Enforcing
Plugin Name catchall_boolean
Host Name blueberry
Platform Linux blueberry 2.6.35.6-45.fc14.i686 #1 SMP Mon
Oct 18 23:56:17 UTC 2010 i686 i686
Alert Count 112
First Seen Sun 14 Nov 2010 09:35:01 AM GMT
Last Seen Sun 14 Nov 2010 09:35:17 AM GMT
Local ID 4d9759c9-e672-475d-bf61-151d1688909a
Line Numbers

Raw Audit Messages

node=blueberry type=AVC msg=audit(1289727317.378:856): avc: denied { mmap_zero } for pid=1880 comm=”kate” scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=memprotect

node=blueberry type=SYSCALL msg=audit(1289727317.378:856): arch=40000003 syscall=192 success=no exit=-13 a0=0 a1=100000 a2=0 a3=4022 items=0 ppid=1629 pid=1880 auid=500 uid=500 gid=500 euid=500 suid=500 fsuid=500 egid=500 sgid=500 fsgid=500 tty=(none) ses=1 comm=”kate” exe=2F7573722F62696E2F6B617465202864656C6574656429 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)

For years I’ve been working with no data loss, but this time I had to revert back to a previously-saved version of a document I worked on and then rewrite bits of it. Perhaps I had enough confidence in the system to only hit save (CTRL+S) once in a very long time. This experience has taught me to save my work more often but more importantly it showed that Fedora can act rather bizarrely where Kubuntu never did. As a result of this behaviour I was unable to save my work. SELinux implies there was an “attack” on the system, but obviously there was not.

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Summary: A weekly roundup with special focus on hands-on experience and impressions of the latest major release of GNU/Linux, namely Fedora 14

HIS is the sixth episode, which has just been recorded by Tim and Roy. This was done right after today’s testing of Fedora and Fusion 14. I installed it permanently on 2 boxes, whereas Tim tried Fusion on his side and, as usual, his site OpenBytes has some show notes. As we’ve both had a chance to test it on some machines, we may also post detailed reviews soon (c.f. [cref 41364 our first show], which was a Fedora 14 special that covered Fusion too).

To summarise my experience in textual form, it was a KDE-only experience and an especially wonderful one. Having just installed Fedora 14 on another box and encountered very few difficulties (ClaudioM and other people who spoke back to me were generally happy with it as well, only with minor pet peeves). I spent many hours on it, getting a feel for what’s installed, what works, and what is harder to use. Among the installations, the first, on a desktop, went smoothly, but the second, a notebook, had the same issue as Mandriva had with it (built-in microphone not detected, so external one needed). There is a lot to be said about the startup speed and about Plasma, which has nonetheless given me a hard time today. Plasma-desktop in KDE (4.5) is very pleasant and it provides a good-looking desktop and brilliant experience. Unfortunately it decided to repeatedly crash on the laptop and it’s possibly simple to resolve (will retry tomorrow).

As time goes on, TechBytes manages to become more focused, concise, and also incorporate a logical structure which makes it easier to follow. We also intend to end every show with a song from now on. This show closes with “On My Kees” from Aqualung (freely obtainable via SXSW 2009 Showcasing Artists).

If you wish to be on the show or know someone who ought to be on the show, please let us know. Marti spoke with us for a long time today, but we are trying to sort out recording difficulties which will hopefully be overcome soon. We are eager to have him on a future show.

As always, if you enjoy this show, please consider recommending it to others and consider subscribing to the show via the RSS feed. If you have an Identi.ca account, consider subscribing to TechBytes in order to keep up to date.

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Direct download as Ogg (2:01:00, 47.6 MB) | Direct download as MP3 (55.4 MB)

Summary: This is the longest show so far and it covers a wide range of topics with no specific item of focus

HIS is the fifth episode, which was recorded last night. OpenBytes has some show notes and the structure of this show has improved somewhat (the show is still not scripted in any way, as a matter of preference).

This show closes with “Axxo” from “Binaerpilot” (binaerpilot.no) (album name is “Nordland”).

If you wish to be on the show or know someone who ought to be on the show, please let us know. As always, if you enjoy this show, please consider recommending it to others and consider subscribing to the show via the RSS feed. If you have an Identi.ca account, consider subscribing to TechBytes in order to keep up to date.

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intend to publish a long overview of Web resources for tagged data. In the mean time, based on the excellent Web page of Zhen Qian I have managed to piece together something for people to play with. From his thesis [PDF] I’ve extracted a series of 6 frames that I’ve produced the above videos from. I’m hoping to receive high-resolution data to test code with, probably later this month. If the data can be legally shared, I will try to ensure people can get it from this Web site so that getting things done becomes less of an unnecessary ordeal to others.

udden change in plans and improvement of research direction leads me to the exploration of MRI tagging, which proves to be difficult when one tries to actually find raw data to work with, not information about it. In the coming days I plan to prepare a post explaining to people where they can obtain tagged data of the brain and the heart (trying to help others solve the problem which occupies many hours of my time). The Internet is extremely mature when it comes to sharing of text and sometimes even audio and film, copyright being an obvious barrier. When it comes to medical data, however, it is another story altogether, even if it’s totally anonymised. Personally, I’ve put 3-D scans of my brain on this Web site, hoping to provide people with the sort of data I sometimes struggle to get a hold of.

Direct download as Ogg (1:18:09, 31.9 MB) | Direct download as MP3 (34.9 MB)

Summary: Tim and Roy discuss Fedora 14 (which Roy installed today), file sharing, DDOS attacks, and they also cover a variety of GNU/Linux distributions

HIS is the fourth episode, which is also the third episode released in 3 days. OpenBytes has some show notes and in the future the structure of the show will be as follows (as per Tim’s suggestion):

1. News headlines summary
2. One discussion point (or guest interview)
3. Feedback
4. Close on highlighted artist

This show closes with a lovely song from the lovely Emma Lee (maybe not the same Emma Lee as the famous one). The song is called “That Sinking Feeling” and it was a free download in SXSW 2009 (Showcasing Artists).

If you wish to be on the show or know someone who ought to be on the show, please let us know. As always, if you enjoy this show, please consider recommending it to others and consider subscribing to the show via the RSS feed. If you have an Identi.ca account, consider subscribing to TechBytes in order to keep up to date.

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Direct download as Ogg (1:14:09, 23.8 MB) | Direct download as MP3 (33.9 MB)

Summary: Tim and Roy discuss today’s news about games, graphics cards, and 3-D effects in GNU/Linux; towards the end of the show the discussion is focused on the competition

HIS is the third episode of our show, which now increases in terms of release pace and audience size. The show is neither scripted nor edited, but it strives to cover all the news that matters and delve into discussions which other Web sites seem to avoid. Show notes can usually be found at OpenBytes, which also posts links of relevance.

In a future show we may speak to “wallclimber”, who contributed a lot to Techrights and will hopefully be on TechBytes some time in January. She requires some preparation, which we too will be doing as the show matures. The interference of background noise has been reduced and the flow of the show will hopefully improve over time, even without any rehearsals.

As always, if you enjoy this show, please consider recommending it to others and consider subscribing to the show via the RSS feed. If you have an Identi.ca account, consider subscribing to TechBytes in order to keep up to date.

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