Re: [PATCH 1/2] mm/kasan: dump alloc/free stack for page allocator
From: Walter Wu
Date: Wed Sep 04 2019 - 21:54:47 EST
On Wed, 2019-09-04 at 10:37 -0400, Qian Cai wrote:
> On Wed, 2019-09-04 at 22:16 +0800, Walter Wu wrote:
> > On Wed, 2019-09-04 at 15:44 +0200, Andrey Konovalov wrote:
> > > On Wed, Sep 4, 2019 at 8:51 AM Walter Wu <walter-zh.wu@xxxxxxxxxxxx> wrote:
> > > > +config KASAN_DUMP_PAGE
> > > > + bool "Dump the page last stack information"
> > > > + depends on KASAN && PAGE_OWNER
> > > > + help
> > > > + By default, KASAN doesn't record alloc/free stack for page
> > > > allocator.
> > > > + It is difficult to fix up page use-after-free issue.
> > > > + This feature depends on page owner to record the last stack of
> > > > page.
> > > > + It is very helpful for solving the page use-after-free or out-
> > > > of-bound.
> > >
> > > I'm not sure if we need a separate config for this. Is there any
> > > reason to not have this enabled by default?
> > PAGE_OWNER need some memory usage, it is not allowed to enable by
> > default in low RAM device. so I create new feature option and the person
> > who wants to use it to enable it.
> Or you can try to look into reducing the memory footprint of PAGE_OWNER to fit
> your needs. It does not always need to be that way.
Thanks your suggestion. We can try to think what can be slimmed.