> -----Original Message-----
> From: David Hildenbrand <david@xxxxxxxxxx>
> Sent: Tuesday, 10 September 2019 5:39 PM
> To: Alastair D'Silva <alastair@xxxxxxxxxxx>; alastair@xxxxxxxxxxx
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>; Oscar Salvador
> <osalvador@xxxxxxxx>; Michal Hocko <mhocko@xxxxxxxx>; Pavel Tatashin
> <pasha.tatashin@xxxxxxxxxx>; Dan Williams <dan.j.williams@xxxxxxxxx>;
> Wei Yang <richard.weiyang@xxxxxxxxx>; Qian Cai <cai@xxxxxx>; Jason
> Gunthorpe <jgg@xxxxxxxx>; Logan Gunthorpe <logang@xxxxxxxxxxxx>; Ira
> Weiny <ira.weiny@xxxxxxxxx>; linux-mm@xxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH 2/2] mm: Add a bounds check in
> devm_memremap_pages()
>
> On 10.09.19 04:52, Alastair D'Silva wrote:
> > From: Alastair D'Silva <alastair@xxxxxxxxxxx>
> >
> > The call to check_hotplug_memory_addressable() validates that the
> > memory is fully addressable.
> >
> > Without this call, it is possible that we may remap pages that is not
> > physically addressable, resulting in bogus section numbers being
> > returned from __section_nr().
> >
> > Signed-off-by: Alastair D'Silva <alastair@xxxxxxxxxxx>
> > ---
> > mm/memremap.c | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > diff --git a/mm/memremap.c b/mm/memremap.c index
> > 86432650f829..fd00993caa3e 100644
> > --- a/mm/memremap.c
> > +++ b/mm/memremap.c
> > @@ -269,6 +269,13 @@ void *devm_memremap_pages(struct device
> *dev,
> > struct dev_pagemap *pgmap)
> >
> > mem_hotplug_begin();
> >
> > + error = check_hotplug_memory_addressable(res->start,
> > + resource_size(res));
> > + if (error) {
> > + mem_hotplug_done();
> > + goto err_checkrange;
> > + }
> > +
>
> No need to check under the memory hotplug lock.
>
Thanks, I'll adjust it.
> > /*
> > * For device private memory we call add_pages() as we only need to
> > * allocate and initialize struct page for the device memory. More-
> > @@ -324,6 +331,7 @@ void *devm_memremap_pages(struct device *dev,
> > struct dev_pagemap *pgmap)
> >
> > err_add_memory:
> > kasan_remove_zero_shadow(__va(res->start), resource_size(res));
> > + err_checkrange:
> > err_kasan:
> > untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
> > err_pfn_remap:
> >
>
>
> --
>
> Thanks,
>
> David / dhildenb
>
--
Alastair D'Silva mob: 0423 762 819
skype: alastair_dsilva msn: alastair@xxxxxxxxxxx
blog: http://alastair.d-silva.org Twitter: @EvilDeece
