[vdr] vdr 1.4.4 / xineliboutput 1.0.0_pre6 causes complete system freeze

[Matthias Dahl]

Hi everyone.

I am currently trying to get away from MythTV (which never lived up to my 
expectations). So far, vdr has been nothing but great. Except for the 
following which just drives me crazy:

Whenever I am using vdr-sfxe or xine-ui to watch tv, switching channels 
sometimes freezes my system hard... except for the Magic SysRq reboot key, 
its totally dead. (no remote logging, no emergency umounting, ...)

So far I have been able to come up with a testcase that reproduces the problem 
or at least some problem...

1) start vdr as demon (with xineliboutput)
2) fire up vdr-sxfe (use a local pipe or rtsp or whatever) or xine xvdr://
3) send a SIGKILL to the frontend process (so either vdr-sxfe or xine)
4) system freezes hard immediately without any logs or whatsoever

I believe this is the same problem I have been expierencing at random. I guess 
what happened previously was that vdr-sxfe or xine died unexpectedly and 
which naturally led to the same result.

What's interesting though, starting vdr directly (not as demon) with the 
xineliboutput, I am unable to reproduce the problem. I can kill the process, 
zap around as much as I want... no problem.

Here some more informations:

- OS: Gentoo ~amd64 (64 bit -hicks-)
- KNC ONE DVB-C Plus with Cineview and Alphacrypt Light CAM
- fresh (a few days old) dvb tree from mercurial repository (linuxtv.org)
- 2.6.19rc6git10 (almost 100% identical to 2.6.19-final)
- xinelib 1.1.3_pre20061129
- vdr 1.4.4 with bigpatch, setup plugin, jumpplay, dvbplayer, cmdsubmenu
  dolby-record-switch, submenu and femon
- xineliboutput 1.0.0_pre6
- gcc 4.1.1 (gentoo rev 2, meaning there are a lot of fixes included and thus
  not vanilla)
- glibc 2.5

Naturally I also tried older kernels and older dvb checkouts but that didn't 
change anything. I do believe now that the problem is somewhere either in vdr 
or in xineliboutput because my system is normally rock solid and I cannot 
force a total freeze with just some dvb apps even if I want to. (believe me, 
I tried)

Being an "computer scientist" myself, I know there is nothing more important 
than debugging the whole thing. Unfortunately that's hard to do when the 
whole system just takes a break. ;-) I tried getting getting some infos out of 
this with gdb but so far nothing turned up. There is also no kernel oops or 
anything like it reported.

The strangest thing about this: vdr runs as vdr:vdr and vdr-sxfe is also 
just a regular user. Actually user processes shouldn't be able to freeze the 
system hard. ;-(

By the way, I also opened up a post over at vdr-portal.de which turned up that 
I am not the only one seeing this problem.

(german) http://www.vdr-portal.de/board/thread.php?postid=548719

I also email Petri (author of xineliboutput) a few days ago with roughly the 
same msg here but I haven't yet received an answer.

Thanks for any help or advice in advance! If there is anything I can do to 
help to get to the bottom of this, I'd be more than glad.

Have a nice weekend,
matthew.