Re: Circular lockdep in kvm_reset_vcpu() ?

Cristian Marussi
2023-03-14T11:05:46Z

On Tue, Mar 14, 2023 at 09:28:25AM +0000, Marc Zyngier wrote:
> On 2023-03-13 18:20, Cristian Marussi wrote:
> > On Mon, Mar 13, 2023 at 02:09:55PM +0000, Marc Zyngier wrote:
>
> > > And -rc2 works just fine here.
> >
> > Thanks, I'll dig deeper what's going on un my setup.
>
> Actually, you really want this patch[1] which is on its
> way to Linus.
>
> It could explain the issue you're seeing with SMP.

Hi Marc,

thanks this just solves for me on JUNO with guest SMP.

Indeed with earlycon on JUNO with SMP I was seeing, beside a lot of
workqueue lockup that finally hanged the guest, some puzzling
'time-traveling' stamps that seemed to align more with the host time
than the guest.

[ 0.509305] thermal_sys: Registered thermal governor 'step_wise'
[ 0.509327] thermal_sys: Registered thermal governor 'power_allocator'
[ 282.404523] audit: type=2000 audit(0.372:1): state=initialized audit_enabled=0 res=1
[ 0.526380] cpuidle: using governor menu
[ 0.530378] hw-breakpoint: found 6 breakpoint and 4 watchpoint registers.
[ 0.536241] ASID allocator initialised with 65536 entries
[ 0.547455] Serial: AMBA PL011 UART driver
[ 0.563267] Callback from call_rcu_tasks() invoked.
[ 282.463816] KASLR disabled due to lack of seed
[ 282.470356] HugeTLB: registered 1.00 GiB page size, pre-allocated 0 pages
[ 282.476182] HugeTLB: 0 KiB vmemmap can be freed for a 1.00 GiB page
....
.....
[ 345.799753] io scheduler bfq registered
[ 126.753573] watchdog: BUG: soft lockup - CPU#0 stuck for 118s! [kworker/u4:0:9]
[ 126.759801] Modules linked in:
[ 126.762397] irq event stamp: 713

Thanks a lot for the help.
Cristian