General Protection Fault with 5.5.0

Using Ardour to record the Katalsky Requiem (big choir, up to hour long takes) with 5.5.0, a Tascam US4x4 crashes with GPF (but not very often).

This is a hopeless bug report because all I can tell you is that you can run for an hour with no problems at all, then 10 minutes into the the next take, bang, window disappears, audio recording lost and the only evidence Ardour was ever there is a journal message:

Mar 02 21:47:06 dh179-66 kernel: traps: ardour-5.5.0[32478] general protection ip:7f460a72521b sp:7f45daffc8b0 error:0
Mar 02 21:47:06 dh179-66 kernel:  in[7f460a6ae000+195000]

So far we’ve lost the last two seconds of one take, and last night two whole takes (didn’t stop the transport in between). So I’m turning to the community for any ideas how to get to the bottom of this. Running on kernel 4.9.6, Debian Stretch. It’s very hard to work out where to start faultfinding when the application works perfectly, except for once in 10^13 machine cycles!

Check if the bug exists in the latest version of Ardour, v5.8.
If you’re lucky, and the bug is in Ardour, it may have been fixed.

I’m sorry to hear that.

There is – that affects some systems only and is not easily reproducible nor understood.
To be safe: disable Preferences > Appearance > Editor > “Show waveforms while recording” (5.8, in 5.5 that setting is probably in Prefs >Editor or elsewhere)

Then again it could be a different issue, would be a way to find out.