Re: [PATCH 1/3] usercopy: Handle vm_map_ram() areas

[Baoquan He <bhe@redhat.com>]

On 06/13/22 at 12:00pm, Uladzislau Rezki wrote:
> > vmalloc does not allocate a vm_struct for vm_map_ram() areas.  That causes
> > us to deny usercopies from those areas.  This affects XFS which uses
> > vm_map_ram() for its directories.
> > 
> > Fix this by calling find_vmap_area() instead of find_vm_area().
> > 
> > Fixes: 0aef499f3172 ("mm/usercopy: Detect vmalloc overruns")
> > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> > ---
> >  include/linux/vmalloc.h | 1 +
> >  mm/usercopy.c           | 8 +++++---
> >  mm/vmalloc.c            | 2 +-
> >  3 files changed, 7 insertions(+), 4 deletions(-)
> > 
> > diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
> > index b159c2789961..096d48aa3437 100644
> > --- a/include/linux/vmalloc.h
> > +++ b/include/linux/vmalloc.h
> > @@ -215,6 +215,7 @@ extern struct vm_struct *__get_vm_area_caller(unsigned long size,
> >  void free_vm_area(struct vm_struct *area);
> >  extern struct vm_struct *remove_vm_area(const void *addr);
> >  extern struct vm_struct *find_vm_area(const void *addr);
> > +struct vmap_area *find_vmap_area(unsigned long addr);
> Make it "extern" since it becomes globally visible?

extern is not suggested any more to add for function declaration in
header file, and removing it doesn't impact thing.

> 
> --
> Uladzislau Rezki
>