fds jumping between processes

From: Lluís Batlle i Rossell
Date: Fri May 14 2010 - 05:09:24 EST


Hello,
here is quite an open bug report... I could not reproduce this again, but it
involves the fds opened of a killed process being passed to another process, or
something like this.

I'm using vanilla 2.6.33.3 in x86_64.
I was using skype, talking through it using alsa, and trying the
'share desktop' feature, it died. Starting it again, it could not open the alsa
device. Using fuser:

...:/dev/snd]$ fuser *
controlC0: 32341
pcmC0D0p: 32341
timer: 32341

Which that was:
$ ps ax | grep 323
32341 ? S 0:01 /home/xxx/.nix-profile/bin/xpdf /tmp/xxx.pdf

So, after skype (using alsa) died, the xpdf process took the soundcard fds
skype had. It does not make much sense xpdf to use sound... so I guess something
worth looking happened.

I don't have more details. Killing xpdf made the new skype open the alsa device
properly.

Sorry for not having analised the situation better. Now I cannot reproduce it
anymore. Maybe this will make someone knowing say "ah, let me look if ...". I
just thought if this is a bug in the kernel, it can involve security problems.

Thank you,
Lluís.
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