| Message ID | 20240328225831.1765286-2-willy@infradead.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Unify vma_address and vma_pgoff_address | expand |
On 28.03.24 23:58, Matthew Wilcox (Oracle) wrote: > If 'page' is the first page of a large folio then vma_address() will scan > for any page in the entire folio. This can lead to page_mapped_in_vma() > returning true if some of the tail pages are mapped and the head page > is not. This could lead to memory failure choosing to kill a task > unnecessarily. > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> > --- > mm/page_vma_mapped.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c > index 74d2de15fb5e..ac48d6284bad 100644 > --- a/mm/page_vma_mapped.c > +++ b/mm/page_vma_mapped.c > @@ -325,6 +325,8 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) > */ > int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma) > { > + struct folio *folio = page_folio(page); > + pgoff_t pgoff = folio->index + folio_page_idx(folio, page); > struct page_vma_mapped_walk pvmw = { > .pfn = page_to_pfn(page), > .nr_pages = 1, > @@ -332,7 +334,7 @@ int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma) > .flags = PVMW_SYNC, > }; > > - pvmw.address = vma_address(page, vma); > + pvmw.address = vma_pgoff_address(pgoff, 1, vma); > if (pvmw.address == -EFAULT) > return 0; > if (!page_vma_mapped_walk(&pvmw)) Reviewed-by: David Hildenbrand <david@redhat.com>
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index 74d2de15fb5e..ac48d6284bad 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -325,6 +325,8 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) */ int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma) { + struct folio *folio = page_folio(page); + pgoff_t pgoff = folio->index + folio_page_idx(folio, page); struct page_vma_mapped_walk pvmw = { .pfn = page_to_pfn(page), .nr_pages = 1, @@ -332,7 +334,7 @@ int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma) .flags = PVMW_SYNC, }; - pvmw.address = vma_address(page, vma); + pvmw.address = vma_pgoff_address(pgoff, 1, vma); if (pvmw.address == -EFAULT) return 0; if (!page_vma_mapped_walk(&pvmw))
If 'page' is the first page of a large folio then vma_address() will scan for any page in the entire folio. This can lead to page_mapped_in_vma() returning true if some of the tail pages are mapped and the head page is not. This could lead to memory failure choosing to kill a task unnecessarily. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> --- mm/page_vma_mapped.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)