The folio_try_get in memfd_alloc_folio is not necessary. Delete it, and
delete the matching folio_put in memfd_pin_folios. This also avoids
leaking a ref if the memfd_alloc_folio call to hugetlb_add_to_page_cache
fails. That error path is also broken in a second way -- when its
folio_put causes the ref to become 0, it will implicitly call
free_huge_folio, but then the path *explicitly* calls free_huge_folio.
Delete the latter.
This is a continuation of the fix
"mm/hugetlb: fix memfd_pin_folios free_huge_pages leak"
Fixes: 89c1905d9c14 ("mm/gup: introduce memfd_pin_folios() for pinning memfd folios")
Suggested-by: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx>
Suggested-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Steve Sistare <steven.sistare@xxxxxxxxxx>
---
mm/gup.c | 4 +---
mm/memfd.c | 3 +--
2 files changed, 2 insertions(+), 5 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index bccabaa..947881ff 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -3618,7 +3618,7 @@ long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end,
pgoff_t start_idx, end_idx, next_idx;
struct folio *folio = NULL;
struct folio_batch fbatch;
- struct hstate *h = NULL;
+ struct hstate *h;
long ret = -EINVAL;
if (start < 0 || start > end || !max_folios)
@@ -3662,8 +3662,6 @@ long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end,
&fbatch);
if (folio) {
folio_put(folio);
- if (h)
- folio_put(folio);
folio = NULL;
}
diff --git a/mm/memfd.c b/mm/memfd.c
index bcb131d..c17c3ea 100644
--- a/mm/memfd.c
+++ b/mm/memfd.c
@@ -89,13 +89,12 @@ struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t idx)
numa_node_id(),
NULL,
gfp_mask);
- if (folio && folio_try_get(folio)) {
+ if (folio) {
err = hugetlb_add_to_page_cache(folio,
memfd->f_mapping,
idx);
if (err) {
folio_put(folio);
- free_huge_folio(folio);
return ERR_PTR(err);
}
folio_unlock(folio);
--
1.8.3.1
