diff mbox series

[RFC,01/13] mm/rmap: fix missing swap_free() in try_to_unmap() after arch_unmap_one() failed

Message ID 20220224122614.94921-2-david@redhat.com (mailing list archive)
State New
Headers show
Series mm: COW fixes part 2: reliable GUP pins of anonymous pages | expand

Commit Message

David Hildenbrand Feb. 24, 2022, 12:26 p.m. UTC
In case arch_unmap_one() fails, we already did a swap_duplicate(). let's
undo that properly via swap_free().

Fixes: ca827d55ebaa ("mm, swap: Add infrastructure for saving page metadata on swap")
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 mm/rmap.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Khalid Aziz Feb. 24, 2022, 4:26 p.m. UTC | #1
On 2/24/22 05:26, David Hildenbrand wrote:
> In case arch_unmap_one() fails, we already did a swap_duplicate(). let's
> undo that properly via swap_free().
> 
> Fixes: ca827d55ebaa ("mm, swap: Add infrastructure for saving page metadata on swap")
> Cc: Khalid Aziz <khalid.aziz@oracle.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>   mm/rmap.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 6a1e8c7f6213..f825aeef61ca 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1625,6 +1625,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
>   				break;
>   			}
>   			if (arch_unmap_one(mm, vma, address, pteval) < 0) {
> +				swap_free(entry);
>   				set_pte_at(mm, address, pvmw.pte, pteval);
>   				ret = false;
>   				page_vma_mapped_walk_done(&pvmw);

That looks reasonable.

Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>

--
Khalid
diff mbox series

Patch

diff --git a/mm/rmap.c b/mm/rmap.c
index 6a1e8c7f6213..f825aeef61ca 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1625,6 +1625,7 @@  static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 				break;
 			}
 			if (arch_unmap_one(mm, vma, address, pteval) < 0) {
+				swap_free(entry);
 				set_pte_at(mm, address, pvmw.pte, pteval);
 				ret = false;
 				page_vma_mapped_walk_done(&pvmw);