VFIO fix for v6.0-rc5

- Fix zero page refcount leak (Alex Williamson)
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Merge tag 'vfio-v6.0-rc5' of https://github.com/awilliam/linux-vfio

Pull VFIO fix from Alex Williamson:

 - Fix zero page refcount leak (Alex Williamson)

* tag 'vfio-v6.0-rc5' of https://github.com/awilliam/linux-vfio:
  vfio/type1: Unpin zero pages
This commit is contained in:
Linus Torvalds 2022-09-09 07:44:33 -04:00
commit 725f3f3b27
1 changed files with 12 additions and 0 deletions

View File

@ -558,6 +558,18 @@ static int vaddr_get_pfns(struct mm_struct *mm, unsigned long vaddr,
ret = pin_user_pages_remote(mm, vaddr, npages, flags | FOLL_LONGTERM, ret = pin_user_pages_remote(mm, vaddr, npages, flags | FOLL_LONGTERM,
pages, NULL, NULL); pages, NULL, NULL);
if (ret > 0) { if (ret > 0) {
int i;
/*
* The zero page is always resident, we don't need to pin it
* and it falls into our invalid/reserved test so we don't
* unpin in put_pfn(). Unpin all zero pages in the batch here.
*/
for (i = 0 ; i < ret; i++) {
if (unlikely(is_zero_pfn(page_to_pfn(pages[i]))))
unpin_user_page(pages[i]);
}
*pfn = page_to_pfn(pages[0]); *pfn = page_to_pfn(pages[0]);
goto done; goto done;
} }