Re: [PATCH] slub: fix unreclaimable slab stat for bulk free

[Kefeng Wang]

On 2021/8/3 22:29, Vlastimil Babka wrote:
> On 8/3/21 4:24 PM, Kefeng Wang wrote:
> > On 2021/7/29 22:03, Shakeel Butt wrote:
> > > On Wed, Jul 28, 2021 at 11:52 PM Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> wrote:
> > > > On 2021/7/28 23:53, Shakeel Butt wrote:
> > > I don't have a strong opinion on this. Please send a patch with
> > > reasoning if you want WARN_ON_ONCE here.
> > Ok, we met a BUG_ON(!PageCompound(page)) in kfree() twice in lts4.4, we are
> > still debugging it.
> >
> > It's different to analyses due to no vmcore, and can't be reproduced.
> >
> > WARN_ON() here could help us to notice the issue.
> >
> > Also is there any experience or known fix/way to debug this kinds of issue?
> > memory corruption?
> This would typically be a use-after-free/double-free - a problem of the slab
> user, not slab itself.

We enable KASAN to find whether or not there are some UAF/double free, 
no related

log for now.

> > Any suggestion will be appreciated, thanks.
> debug_pagealloc could help to catch a use-after-free earlier

OK, will try this, thanks.

> > > .
> .