[linux-dvb] [Patch] Error in dvb_net.c on 64bit platforms

Holger Kiehl Holger.Kiehl at dwd.de
Tue Nov 1 09:35:27 CET 2005


On Mon, 31 Oct 2005, Ralph Metzler wrote:

> Holger Kiehl writes:
> > > from that person if this suffices to remove the race. So, if you or
> > > anybody else with SMP can test it that would be great.
> > >
> > Yes, this fixes the oops. I have made a lot of tests and was unable
> > to reproduce the oops with your dvb_net.c.
>
> Good to hear.
> Thanks for the testing.
>
>
> > Thanks for the quick responce and fix! Hope this will soon go into the
> > kernel. This also fixes the issue that one could no longer reboot or
> > poweroff the system and I think there where some reports on this too.
> >
> > > The could of course be something else showing up onl on 64 bit.
> > > Does this ooops also happen on 32 bit SMP?
> > >
> > Just recently I have setup and tested a 32 bit system with SMP kernel
> > and there where no such issues, but it had the Nova-S card. The 64 bit
> > system I am now testing has the skystar card. Tomorrow I will try
> > and see if I can get another system with 32 bit and the skystar.
>
> I think this race is much more likely on drivers where the stop_feed
> call has some kind of waiting (e.g. for the hardware response) in it
> because then the chances that the two processes using the filters
> happen at the same time are very high.
> So, cards with hardware PID filters like the Skystar card will
> expose the race much more often.
>
Yes, you are right. With skystar and 32 bit the SMP system does oops.
But I noticed that 2.6.12 was still okay and as of 2.6.13 and up it
oopses.

Thanks for the quick help!

Holger




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