Channel Scan Crashes at 100%

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marynya
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Channel Scan Crashes at 100%

Post by marynya » Sun Sep 20, 2020 7:04 pm

Fedora 32 Linux
MythTV 31.0 (Fedora repository)
MariaDB 10.4.14
Hauppauge tuner card (PCI)

mythtv-setup channel scan crashes at 100% (after showing channels found) with the following output:

-------------------------------------
2020-09-06 13:30:20.023824 E [8912/9093] SignalMonitor recorders/dvbchannel.cpp:1196:GetSNR DVBChan[1](/dev/dvb/adapter0/frontend0): Getting Frontend signal/noise ratio failed.
eno: Invalid argument (22)

Scan parameters:
Desired Services : tv
Unencrypted Only : yes
Logical Channel Numbers only: yes
Complete scan data required : yes
Full search for old channels: yes
Remove duplicate channels : yes
/usr/include/c++/10/bits/stl_vector.h:1045: std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](std::vector<_Tp, _Alloc>::size_type) [with _Tp = ChannelInsertInfo; _Alloc = std::allocator<ChannelInsertInfo>; std::vector<_Tp, _Alloc>::reference = ChannelInsertInfo&; std::vector<_Tp, _Alloc>::size_type = long unsigned int]: Assertion '__builtin_expect(__n < this->size(), true)' failed.
Handling Aborted
Aborted (core dumped)
----------------------------------------

This occurs even if I delete mythcoverg and rebuild the configuration from scratch. I assumed this was due to the known MariaDB bug but that is supposed to be fixed in 10.4.14 and everything else appears to be working. I have certain channels which will not lock on "Play TV" and which show no data in the listings. If recorded, no file is created. Other channels are fine, as are optical and file playback. Everything was working until recently. It was about the time some channels changed their format but the MariaDB problem showed up at about the same time. I don't see references to this problem so It is likely something specific to my system but it has eluded me so far.

Any suggestions would be welcome.

Mike

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kmdewaal
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Re: Channel Scan Crashes at 100%

Post by kmdewaal » Sun Sep 20, 2020 9:19 pm

The MariaDB bug is, if memory serves me right, fixed in 10.4.15 but this should not influence mythtv-setup.
That the crash happens at 100% complete might indicate that this caused by option processing which is done after scanning.
You could try doing scans with different options, e.g. "Remove duplicate channels" to no, or "Full search for old channels" to no, and see if that makes a difference.

To investigate what happens I would like to have a full debug log of the complete scan, start this like this:

Code: Select all

mythtv-setup -v channel,chanscan,record,siparser --loglevel=debug
and capture all output. If the (gzipped) file is too big to post here you use e.g. pastebin or wetransfer or gmail to me directly.
I would also like a gdb backtrace. Can you make a backtrace like this:

Code: Select all

gdb mythtv-setup
<do the scan>
gdb> thread apply all bt full
and post that also.

Thanks,
Klaas.

marynya
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Re: Channel Scan Crashes at 100%

Post by marynya » Mon Sep 21, 2020 12:37 am

Klass

I turned all options off and it worked so I put them back one at a time and it appears to be the "Logical Channel Number Required" option which causes the crash. All of the others can be on. I am not entirely sure what that does but leaving it off appears to be an adequate work-around for my purposes. The scan got me all of my channels back. Is this something you would want to look into further, or perhaps I should file a formal bug report. It looks less like something specific to my system.

Thanks for the Help!

Mike

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kmdewaal
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Re: Channel Scan Crashes at 100%

Post by kmdewaal » Mon Sep 21, 2020 5:49 am

Glad that it works for you now and this is definitely a bug in mythtv-setup that needs to be fixed. Please create a bug report (that is in Github nowadays) if possible and attach the log and the traceback.

marynya
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Re: Channel Scan Crashes at 100%

Post by marynya » Mon Sep 21, 2020 6:43 pm

Thanks again for the help and for the instruction in creating the log files. I will see if I can file a useful bug report.

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kmdewaal
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Re: Channel Scan Crashes at 100%

Post by kmdewaal » Wed Sep 23, 2020 7:42 am

I did have a look at the code but I cannot find something obviously wrong. If you can send just the log file and the gdb backtrace that would be great.

Thanks,
Klaas.

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Re: Channel Scan Crashes at 100%

Post by rpress » Tue May 04, 2021 5:02 pm

I'm also seeing a similar crash. I am setting it up for the first time with Fedora 34. Tuner is the HDHR-US.

I tried changing the scan options around but I couldn't ever get it to succeed.

I have logs on pastebin under "tq14CLq4"
Last edited by Steve Goodey on Tue May 04, 2021 6:58 pm, edited 1 time in total.
Reason: Pastebin link added.

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kmdewaal
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Re: Channel Scan Crashes at 100%

Post by kmdewaal » Tue May 04, 2021 6:27 pm

Thanks for the log. It looks like this could also be the "Logical Channel Numbers required" option. The previous poster @marynya indicated this.
Have you tried unchecking the "Logical Channel Numbers required" option?

Can you please log the complete output of mythtv-setup when started with the following options:

Code: Select all

mythtv-setup -v general,channel,chanscan,record,siparser --loglevel=debug --logpath=.
This will create a logfile like this: mythtv-setup.20200815184540.1094946.log in the current directory but then with the actual date and time.
It looks like the gdb traceback in the pastebin is not complete. You can capture all gdb output like this:

Code: Select all

gdb> set logging on
gdb mythtv-setup
gdb>set logging on
gdb>run
<do the scan>
<wait until the crash>
gdb> thread apply all bt full
gdb>set logging off
This will copy all gdb output to the file gdb.txt.
Please post the mythtv-setup log and the gdb.txt file; pastebin works OK for me.

Thanks,
Klaas.

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Re: Channel Scan Crashes at 100%

Post by dhighley » Sun Jun 27, 2021 7:05 pm

Has this issue been resolved? I have been hitting this failure. I have looked for the issue in the trac problem reports but do not find it. I have used Mythtv on Fedora for decades but had a system update failure with Fedora 34 so I decided it is time to rebuild from the ground up. Has anyone been successful in installing Rpmfusion packages on Fedora 34 and getting it to run. My experience so far before the update failure was frontend audio no longer worked.

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kmdewaal
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Re: Channel Scan Crashes at 100%

Post by kmdewaal » Sun Jun 27, 2021 8:32 pm

About the Channel Scan Crash at 100%, no, it has not been resolved. I just had a new look at the logs posted but I cannot find enough hints to go forward.
Can you please make a scan with these options and post that somewhere?

Code: Select all

mythtv-setup -v channel,chanscan,record,siparser --loglevel=debug
This will be too big to attach here but pastebin or gmail usually works.

One possible cause can be the channel frequencies that are generated by the scan. In the pastebin log of May 4th there are some messages that suggests that there are invalid channel identification strings generated.
Can you please give the details about:
- HDHomeRun device type (if you are using a HDHomeRun, if you are using another device then please the information about that device)
- Selected frequency table and what else you have configured with this scan that might be of interest
- Signal source (OTA, cable etc)

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Re: Channel Scan Crashes at 100%

Post by dhighley » Wed Jul 07, 2021 4:53 am

Okay, I have a log file 224935 bytes when compressed. How do I get it to you?

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kmdewaal
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Re: Channel Scan Crashes at 100%

Post by kmdewaal » Wed Jul 07, 2021 5:47 am

OK, great! You can use pastebin.com and post the link here or you can send it directly to me klaas.de.waal at gmail dot com

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Re: Channel Scan Crashes at 100%

Post by dhighley » Wed Jul 07, 2021 4:08 pm

Seems pastebin has its limits too. So you can pick up the file here, http://www.highley-recommended.com/mythtv-setup.log.bz2

The setup program seems to have many issues. If you click on exit during a scan it core dumps. If the screen times out or it looses focus then you can no longer interact with setup. Not sure if it will work beyond these issues as trying to setup HDhomerun Prime I see no tuner field. When I added Schedules Direct for the guide it does not as for a password. Sure wish the web interface was able to do a complete configuration.

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Re: Channel Scan Crashes at 100%

Post by dhighley » Fri Jul 09, 2021 5:19 pm

Were you able to pickup the log file and has it provided any useful information?

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kmdewaal
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Re: Channel Scan Crashes at 100%

Post by kmdewaal » Sat Jul 10, 2021 6:28 pm

Yes, I have picked the logfile. Thanks!
It does show that there are many ATSC-specific tables that are not parsed by MythTV which might explain why the callsigns are not extracted. However, this is not new behavior and it does not explain the crash. As to why it crashes I have not come much further.
I did wonder if this thread viewtopic.php?f=36&t=4500 is relevant for you. It appears that with a HDHomeRun Prime you do not have to do a channel scan at all but you can import all channels from SchedulesDirect.

About the loss of focus, this I can reproduce when using Wayland and with v31. With the current master on Wayland there is no loss of focus. There are huge differences between the video code in v31 and in master so it is not simply a case of backporting a single fix.
You could consider changing to an X11 window manager instead of something like Wayland; I expect the loss of focus then will not happen. Or you can switch to master.

About crashing when clicking on Exit while doing a scan. This is something I have not been able to reproduce.

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