Re: WARNING: CPU: 1 PID: 15 at kernel/sched/sched.h:804 assert_clock_updated.isra.62.part.63+0x25/0x27

[Ingo Molnar <mingo@kernel.org>]

* Mike Galbraith <efault@gmx.de> wrote:

> On Tue, 2017-01-31 at 08:28 +0100, Ingo Molnar wrote:
> > * Mike Galbraith <efault@gmx.de> wrote:
> > 
> > > On Mon, 2017-01-30 at 11:59 +0000, Matt Fleming wrote:
> > > > On Sat, 28 Jan, at 08:21:05AM, Mike Galbraith wrote:
> > > > > Running Steven's hotplug stress script in tip.today.  Config is
> > > > > NOPREEMPT, tune for maximum build time (enterprise default-ish).
> > > > > 
> > > > > [   75.268049] x86: Booting SMP configuration:
> > > > > [   75.268052] smpboot: Booting Node 0 Processor 1 APIC 0x2
> > > > > [   75.279994] smpboot: Booting Node 0 Processor 2 APIC 0x4
> > > > > [   75.294617] smpboot: Booting Node 0 Processor 4 APIC 0x1
> > > > > [   75.310698] smpboot: Booting Node 0 Processor 5 APIC 0x3
> > > > > [   75.359056] smpboot: CPU 3 is now offline
> > > > > [   75.415505] smpboot: CPU 4 is now offline
> > > > > [   75.479985] smpboot: CPU 5 is now offline
> > > > > [   75.550674] ------------[ cut here ]------------
> > > > > [   75.550678] WARNING: CPU: 1 PID: 15 at kernel/sched/sched.h:804
> > > > > assert_clock_updated.isra.62.part.63+0x25/0x27
> > > > > [   75.550679] rq->clock_update_flags < RQCF_ACT_SKIP
> > > > 
> > > > The following patch queued in tip/sched/core should fix this issue:
> > > 
> > > Weeell, I'll have to take your word for it, as tip g35669bb7fd46 grew
> > > an early boot brick problem.
> > 
> > That's bad - could you perhaps try to bisect it? All recently queued up patches 
> > that could cause such problems should be readily bisectable.
> > 
> > The bisection might be faster if you first checked whether 5bf728f02218 works - if 
> > it does then the bug is in the patches in WIP.x86/boot or WIP.x86/fpu.
> 
> Fast ain't gonna happen, 5bf728f02218 bricked.

:-/

Next point would be f9a42e0d58cf I suspect, to establish that Linus's latest 
kernel is fine. That means it's in one of the ~200 -tip commits - should be 
bisectable in 8-10 steps from that point on.

Thanks,

	Ingo