Opened 11 years ago

Closed 11 years ago

#4645 closed defect (wontfix)

SVN # 15927 - mythtv-setup - channel scanner constantly segfaults while scanning

Reported by: dstrang@… Owned by: danielk
Priority: blocker Milestone: 0.22
Component: channelscan Version: head
Severity: medium Keywords:
Cc: Stuart Auchterlonie Ticket locked: no

Description

Since the merge of multirec to trunk (and possibly before), the mythtv-setup scanner crashes in the middle of the scan. This happens on both DVB-S, OTA, and an HDHomeRun connected to Comcast cable.

The scanner in 0.20-fixes works just fine, however constantly downgrading to scan is a bit of a pain.

The attached log and backtrace are from scanning with an HDHomeRun set to unencrypted channels only. The following options were selected:

Frequency Table: Cable Modulation: QAM-256 ATSC Channel Seperator: (5.1) Period Existing Channel Treatment: Minimal Updates

I get the same crashes scanning 8VSB with my Air2PC/AirStar 2 ATSC 1st generation card.

Attachments (4)

gdb.txt (14.9 KB) - added by anonymous 11 years ago.
output.txt (84.3 KB) - added by dstrang@… 11 years ago.
mythtv-setup -v all > output.txt
0.21-fixes.rev.16058.gdb.txt (29.8 KB) - added by dstrang@… 11 years ago.
gdb dump of mythtv-setup channel scanner crash from 0.21-fixes rev 16058
0.21-fixes.rev.16058.output.txt (84.4 KB) - added by dstrang@… 11 years ago.
output.txt from mythtv-setup channel scanner crash from 0.21-fixes rev 16058

Download all attachments as: .zip

Change History (17)

Changed 11 years ago by anonymous

Attachment: gdb.txt added

Changed 11 years ago by dstrang@…

Attachment: output.txt added

mythtv-setup -v all > output.txt

comment:1 Changed 11 years ago by stuartm

Milestone: unknown0.21

Changed 11 years ago by dstrang@…

gdb dump of mythtv-setup channel scanner crash from 0.21-fixes rev 16058

Changed 11 years ago by dstrang@…

output.txt from mythtv-setup channel scanner crash from 0.21-fixes rev 16058

comment:2 Changed 11 years ago by dstrang@…

Some additional information; I tested this against the latest 0.21-fixes branch today, the problem still exists. When scanning 8VSB on my Air2PC/AirStar 2 ATSC card, the scanner appears to work but the GUI locks up at the end. It sometimes takes multiple scans to get all the OTA channels. As for the HDHomeRun, it continues to crash after scanning just 4-5 channels, it never finishes a complete scan.

Here are my compile options for mythtv;

./configure --prefix=/usr --enable-dvb --disable-dbox2 --disable-joystick-menu --enable-hdhomerun --enable-opengl-vsync --enable-opengl-video --enable-mmx --compile-type=debug --enable-valgrind

NOTE: the debug & valgrind were added just to do the backtrace.

comment:3 Changed 11 years ago by Stuart Auchterlonie

Cc: Stuart Auchterlonie added

comment:4 Changed 11 years ago by billybobjones2112@…

I was about to open a very similiar bug. The trunk release consistently cores immeduately when trying to scan DVB-S (QPSK). There is a thread on the DVBN forum where multiple users are complaining about the same issue. I am a little worried that this one seems to have morphed into a an 8VSB specific issue.

note to ijr - please let me know if I should open an additional bug with all logs, etc

comment:5 Changed 11 years ago by concordfta <dragozet@…>

I can also confirm this bug. Last tested trunk svn 16133. Using a HDhomerun in 8VSB mode. Scanning segfaults in Mythtv-setup on first proper 8vsb atsc channel found during scan. Playing with hdhr time-outs did not correct problem.

comment:6 Changed 11 years ago by danielk

Component: mythtvchannelscan
Milestone: 0.210.22
Owner: changed from Isaac Richards to danielk

comment:7 Changed 11 years ago by anonymous

Just to comment -t his is still going on in SVN as of today. It's really annoying because without the channel scan working it is hard to get going.

It is inconsistant as well because it works maybe 1/15 times. Must be a race condition.

comment:8 Changed 11 years ago by anonymous

One other comment.... personally I fid if I use 'space' to select 'Next' instead of the enter key, the crash does not seem to happen hardly ever. So maybe it is due to enter key bindings.

comment:9 in reply to:  8 Changed 11 years ago by anonymous

Using space or enter does not matter here. Usually segfaulting, sometimes even C++ abort. Need to check in more details why this happens, but have to agree that it practically renders whole 0.21-fixes and later mythtv unusable state here :|.

comment:10 Changed 11 years ago by laga

Does it work if you bind mythtv-setup to one CPU?

taskset -c 0 /usr/bin/mythtv-setup.real

Of course, this only applies for those with SMP boxes :)

comment:11 Changed 11 years ago by anonymous

Yes, this is dual-cpu box, but enabling valgrind with full leak checked made scanner work ok :) Will try forcing to one cpu only.

comment:12 in reply to:  11 Changed 11 years ago by anonymous

Replying to anonymous:

Yes, this is dual-cpu box, but enabling valgrind with full leak checked made scanner work ok :) Will try forcing to one cpu only.

Yep. Taskset to single cpu seems to have fixed the problem.

comment:13 Changed 11 years ago by danielk

Resolution: wontfix
Status: newclosed

Use the taskset workaround for 0.21.

This doesn't happen with the scanner in the channel scan branch, but that uses a completely different UI infrastructure.

I'm marking this as won't fix, since the code causing the segfault will be replaced before 0.22.

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