Re: [PATCH] mm: fix racing of vb->va when kasan enabled

[Zhaoyang Huang]

On Mon, Jun 20, 2022 at 6:44 PM Uladzislau Rezki <urezki@xxxxxxxxx> wrote:
>
> > > >
> > > Is it easy to reproduce? If so could you please describe the steps? As i see
> > > the freeing of the "vb" is RCU safe whereas vb->va is not. But from the first
> > > glance i do not see how it can accessed twice. Hm..
> > It was raised from a monkey test on A13_k515 system and got 1/20 pcs
> > failed. IMO, vb->va which out of vmap_purge_lock protection could race
> > with a concurrent ra freeing within __purge_vmap_area_lazy.
> >
> Do you have exact steps how you run "monkey" test?
There are about 30+ kos inserted during startup which could be a
specific criteria for reproduction. Do you have doubts about the test
result or the solution?
>
> --
> Uladzislau Rezki