[mythtv] Ticket #1578: Mythfrontend segfault w/dvb radio PID type(private-sec 0x5), MHEG?

[Mark Buechler]

Question, do all packets have CRCs? Is it possible a packet simply doesn't
have one?

- Mark.

On 4/12/06, Daniel Kristjansson <danielk at cuymedia.net> wrote:
>
> On Wed, 2006-04-12 at 16:23 -0400, Mark Buechler wrote:
> > Daniel, I don't wish to bug, but I was wondering if you had a few
> > minutes to look at this one. I'm sure it's something simple but I
> > don't know enough about TS packets to really know what I'm looking at.
>
> Ok, so since we are in the "if (is_start)" portion handle_packet()
> it looks like this is the first TS packet of a PES packet.
>
> Then it looks like the length of the adaptation field is zero
> since len == 0. This is the case for most PES packets.
>
> Then it looks like we call write_section_data() with
> a length of "p_end - p" which in this case is 183 bytes,
> this again is normal.
>
> So it looks like the problem is somewhere within the write_section_data
> function.
>
> Anyway, it looks like section_h_size is 37 when it crashed, which is
> a bit on the short side, even for a PAT packet. Is this happening
> on the first trip through the "while (1)" loop, or has some bad data
> gotten in there (it looks like the first time, since section_index
> hasn't been shrunk from the original 183). Was the CRC checked?
> It looks like we keep trying to parse the packet even if the CRC
> fails, which seems wrong to me; though in truth it shouldn't cause
> a segfault since section_index always gets shrunk when we copy
> the data.
>
> I hope this helps, I recommend printing out the section_index
> and section_h_size before you enter the loop, and then printing
> the results of each step of the parsing in the loop. Then wait
> for a segfault and then look at the last lines of the log.
>
> -- Daniel
>
>
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