On Sat, Nov 15, 2014 at 01:36:41AM +0100, Thomas Gleixner wrote:
> On Fri, 14 Nov 2014, Dave Jones wrote:
>
> > On Fri, Nov 14, 2014 at 11:55:30PM +0100, Thomas Gleixner wrote:
> >
> > > So this looks more like a smp function call fuckup.
> > >
> > > I assume Dave is running that stuff on KVM. So it might be worth while
> > > to look at the IPI magic there.
> >
> > no, bare metal.
>
> Ok, but that does not change the fact that we are stuck in
> smp_function_call land.
>
> Enabling softlockup_all_cpu_backtrace will probably not help much as
> we will end up waiting for csd_lock again :(
>
> Is the machine still accesible when this happens? If yes, we might
> enable a few trace points and functions and read out the trace
> buffer. If not, we could just panic the machine and dump the trace
> buffer over serial.
No, it wedges solid. Even though it says something like "CPU3 locked up",
aparently all cores also get stuck.
9 times out of 10 it doesn't stay alive long enough to even get the full
trace out over usb-serial.
Dave
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