On Thu, 2017-04-06 at 17:04 +1000, Michael Neuling wrote: > We see this usually on boot but can also see it if we kill a getty attached to > tty (which is then respawned by systemd). It seems like we are flushing data > to > a tty at the same time as it's being torn down and restarted. > > I did try the below patch which avoids the crash but locks up one of the > CPUs. I > guess the data never gets flushed if we say nothing is processed. > > This is on powerpc but has also been reported by parisc. > > I'm not at all familiar with the tty layer and looking at the locks, mutexes, > semaphores and reference counting in there scares the hell out of me. > > If anyone has an idea, I'm happy to try a patch.
Note that we noticed one path that called reinit without the ldisc lock held for writing, we added that, but it didn't fix the problem. Cheers, Ben.
