Re: Current mainline git (24e700e291d52bd2) hangs when building e.g. perf

From: Markus Trippelsdorf
Date: Thu Sep 07 2017 - 02:28:53 EST


On 2017.09.06 at 15:15 +0200, Markus Trippelsdorf wrote:
> On 2017.09.06 at 14:52 +0200, Thomas Gleixner wrote:
> > On Tue, 5 Sep 2017, Markus Trippelsdorf wrote:
> > > On 2017.09.05 at 10:53 +0200, Peter Zijlstra wrote:
> > > > > Any ideas on how to debug this further?
> > > >
> > > > So you have a (real) serial line on that box?
> > >
> > > Sadly, no. But hopefully somebody else (with a proper kernel debugging
> > > setup) will reproduce the issue soon.
> >
> > Does the machine respond to ping or is it entirely dead?
>
> It is entirely dead and doesn't respond to ping.

The bug even kills the host (running 4.13) when running 24e700e2 in qemu
(kvm) and compiling stuff in parallel in the guest.
I see an RCU CPU stall in dmesg (on the host), but unfortunately cannot
save it, because nothing gets written to disk after the stall.
Connecting to qemu via gdb also doesn't work.

--
Markus