Re: [PATCH] mm/kasan: Don't vfree() nonexistent vm_area.

[Andrew Morton]

On Tue, 22 May 2018 19:44:06 +0300 Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> wrote:

> > Obviously we can't call vfree() to free memory that wasn't allocated via
> > vmalloc(). Use find_vm_area() to see if we can call vfree().
> > 
> > Unfortunately it's a bit tricky to properly unmap and free shadow allocated
> > during boot, so we'll have to keep it. If memory will come online again
> > that shadow will be reused.
> > 
> > Fixes: fa69b5989bb0 ("mm/kasan: add support for memory hotplug")
> > Reported-by: Paul Menzel <pmenzel+linux-kasan-dev@xxxxxxxxxxxxx>
> > Signed-off-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
> > Cc: <stable@xxxxxxxxxxxxxxx>
> > ---
> 
> This seems stuck in -mm. Andrew, can we proceed?

OK.

Should there be a code comment explaining the situation that Matthew
asked about?  It's rather obscure.