Re: [PATCH 1/3] mm, page_alloc: do not rely on the order of page_poison and init_on_alloc/free parameters

[David Hildenbrand]

On 27.10.20 10:58, Vlastimil Babka wrote:
> On 10/27/20 10:03 AM, David Hildenbrand wrote:
> > On 26.10.20 18:33, Vlastimil Babka wrote:
> > > Enabling page_poison=1 together with init_on_alloc=1 or init_on_free=1 produces
> > > a warning in dmesg that page_poison takes precendence. However, as these
> > > warnings are printed in early_param handlers for init_on_alloc/free, they are
> > > not printed if page_poison is enabled later on the command line (handlers are
> > > called in the order of their parameters), or when init_on_alloc/free is always
> > > enabled by the respective config option - before the page_poison early param
> > > handler is called, it is not considered to be enabled. This is inconsistent.
> > >
> > > We can remove the dependency on order by making the init_on_* parameters only
> > > set a boolean variable, and postponing the evaluation after all early params
> > > have been processed. Introduce a new init_mem_debugging() function for that,
> > > and move the related debug_pagealloc processing there as well.
> >
> > init_mem_debugging() is somewhat sub-optimal - init_on_alloc=1 or
> > init_on_free=1 are rather security hardening mechanisms.
>
> Well yeah, init_mem_debugging_and_hardening()?

Would work for me.

--
Thanks,

David / dhildenb