[CentOS-virt] Status of reverted Linux patch "tty: Fix ldisc crash on reopened tty", Linux 4.9 kernel frequent crashes

Wed Aug 30 20:10:14 UTC 2017
Pasi Kärkkäinen <pasik at iki.fi>

Hello everyone,

Recently Nathan March reported on centos-virt list he's getting frequent Linux kernel crashes with Linux 4.9 LTS kernel because of the missing patch "tty: Fix ldisc crash on reopened tty".

The patch was already merged upstream here:

but then reverted here:

Nathan confirmed if he applies the patch from 71472fa9c52b1da27663c275d416d8654b905f05 to his Linux 4.9 LTS kernel the bug/problem goes away, so the patch (or similar fix) is still needed, at least for 4.9 LTS kernel.

Mikulas reported he's able to trigger the same crash on Linux 4.10:

Michael Neuling reported he's able to trigger the bug on PowerPC:

So now the question is.. is anyone currently working on getting this patch fixed and applied upstream? I think one of the problems earlier was being able to reliable reproduce the crash.. Nathan says he's able to reproduce it many times per week on his environment on x86_64.

Thanks a lot,

-- Pasi