On Sun, Mar 03, 2024 at 11:08:17PM -0800, Saurabh Singh Sengar wrote:
> On Mon, Mar 04, 2024 at 06:24:27AM +0000, Wei Liu wrote:
> > On Sun, Mar 03, 2024 at 12:01:36AM -0800, Saurabh Sengar wrote:
> > > Currently, the secondary CPUs in Hyper-V VTL context lack support for
> > > parallel startup. Therefore, relying on the single initial_stack fetched
> > > from the current task structure suffices for all vCPUs.
> > >
> > > However, common initial_stack risks stack corruption when parallel startup
> > > is enabled. In order to facilitate parallel startup, use the initial_stack
> > > from the per CPU idle thread instead of the current task.
> > >
> > > Fixes: 18415f33e2ac ("cpu/hotplug: Allow "parallel" bringup up to CPUHP_BP_KICK_AP_STATE")
> >
> > I don't think this patch is buggy. Instead, it exposes an assumption in
> > the VTL code. So this either should be dropped or point to the patch
> > which introduces the assumption.
> >
> > Let me know what you would prefer.
>
> The VTL code will crash if this fix is not present post above mentioned patch:
> 18415f33e2ac ("cpu/hotplug: Allow "parallel" bringup up to CPUHP_BP_KICK_AP_STATE").
> So I would prefer a fixes which added the assumption in VTL:
>
> Fixes: 3be1bc2fe9d2 ("x86/hyperv: VTL support for Hyper-V")
>
> Please let me know if you need V4 for it.
No need to repost. I can change the commit message.
Thanks,
Wei.
