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Opened 5 years ago
Closed 5 years ago
#4734 closed defect (duplicate)
MythTV gets stuck tuning going from IVTV -> DVB
| Reported by: | Mark Buechler <Mark.Buechler@…> | Owned by: | ijr |
|---|---|---|---|
| Priority: | minor | Milestone: | unknown |
| Component: | mythtv | Version: | head |
| Severity: | medium | Keywords: | |
| Cc: | Ticket locked: | no |
Description
MythTV gets stuck when changing from an IVTV channel to a DVB channel. The frontend times out on socket communications and will not work until the backend is kicked.
Backtrace, frontend and backend logs attached. The backtrace log has a couple backtraces in it as well as some stepping.
Attachments (5)
Change History (12)
Changed 5 years ago by Mark Buechler <Mark.Buechler@…>
Changed 5 years ago by Mark Buechler <Mark.Buechler@…>
Backend log
Changed 5 years ago by Mark Buechler <Mark.Buechler@…>
Frontend log
comment:1 Changed 5 years ago by Mark Buechler <Mark.Buechler@…>
I believe thread 8 is the culprit here. It looks to be spinning on ThreadedFileWriter::Write() on "while (count > BufFree?())"
Could tearing down the RingBuffer? cause a scenario where count will always be > BufFree?()?
- Mark.
comment:2 Changed 5 years ago by Shane Shrybman <gnome42@…>
Hi Mark,
I can't reproduce the problem and I haven't analyzed the actual cause of this too closely but it doesn't seem inconceivable that you could get stuck in that loop.
Patch attached to safeguard against that.
Changed 5 years ago by Shane Shrybman <gnome42@…>
Changed 5 years ago by Mark Buechler <Mark.Buechler@…>
Several backtraces..
comment:3 Changed 5 years ago by Mark Buechler <Mark.Buechler@…>
It seems there's a few things going on here. Attached a log of several backtraces. I'll analyze it tomorrow when I'm more awake.
- Mark.
comment:4 Changed 5 years ago by laga
Mark,
did you ever get around to looking into this?
comment:5 Changed 5 years ago by Mark Buechler <Mark.Buechler@…>
Yes, I believe it's due to reclist_lock getting locked in the scheduler and never getting released. In trying to narrow it down, I added a bunch of debug printf's, but they changing the timing of events ever so slightly as to nearly prevent the issue altogether.
- Mark.
comment:6 Changed 5 years ago by gnome42
From the bt of thread 8
RingBuffer::Write (this=0xa715b058, buf=0xa205e008, count=2211632) at RingBuffer?.cpp:1182
ThreadedFileWriter::TFW_DEF_BUF_SIZE = 2*1024*1024 => 2097152
2211632 > 2097152 so the (count > BufFree?()) condition will never clear.
comment:7 Changed 5 years ago by Dibblah
- Resolution set to duplicate
- Status changed from new to closed
Backend log