On 2018-12-07 7:28 pm, Souptick Joarder wrote:
On Fri, Dec 7, 2018 at 10:41 PM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
On Fri, Dec 07, 2018 at 03:34:56PM +0000, Robin Murphy wrote:
+int vm_insert_range(struct vm_area_struct *vma, unsigned long addr,
+ struct page **pages, unsigned long page_count)
+{
+ unsigned long uaddr = addr;
+ int ret = 0, i;
Some of the sites being replaced were effectively ensuring that vma and
pages were mutually compatible as an initial condition - would it be worth
adding something here for robustness, e.g.:
+ if (page_count != vma_pages(vma))
+ return -ENXIO;
I think we want to allow this to be used to populate part of a VMA.
So perhaps:
if (page_count > vma_pages(vma))
return -ENXIO;
Ok, This can be added.
I think Patch [2/9] is the only leftover place where this
check could be removed.
Right, 9/9 could also have relied on my stricter check here, but since
it's really testing whether it actually managed to allocate vma_pages()
worth of pages earlier, Matthew's more lenient version won't help for
that one. (Why privcmd_buf_mmap() doesn't clean up and return an error
as soon as that allocation loop fails, without taking the mutex under
which it still does a bunch more pointless work to only undo it again,
is a mind-boggling mystery, but that's not our problem here...)
Robin.
