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authorBui Quang Minh <minhquangbui99@gmail.com>2021-11-20 03:43:40 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-20 21:35:54 +0300
commitafe041c2d0febd83698b8b0164e6b3b1dfae0b66 (patch)
tree9f594be76a840658faf441faa4bb8cdeb48211b7 /mm
parent34dbc3aaf5d9e89ba6cc5e24add9458c21ab1950 (diff)
downloadlinux-afe041c2d0febd83698b8b0164e6b3b1dfae0b66.tar.xz
hugetlb: fix hugetlb cgroup refcounting during mremap
When hugetlb_vm_op_open() is called during copy_vma(), we may take the reference to resv_map->css. Later, when clearing the reservation pointer of old_vma after transferring it to new_vma, we forget to drop the reference to resv_map->css. This leads to a reference leak of css. Fixes this by adding a check to drop reservation css reference in clear_vma_resv_huge_pages() Link: https://lkml.kernel.org/r/20211113154412.91134-1-minhquangbui99@gmail.com Fixes: 550a7d60bd5e35 ("mm, hugepages: add mremap() support for hugepage backed vma") Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Mina Almasry <almasrymina@google.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/hugetlb.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e09159c957e3..3a2479003ddf 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1037,8 +1037,10 @@ void clear_vma_resv_huge_pages(struct vm_area_struct *vma)
*/
struct resv_map *reservations = vma_resv_map(vma);
- if (reservations && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
+ if (reservations && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
+ resv_map_put_hugetlb_cgroup_uncharge_info(reservations);
kref_put(&reservations->refs, resv_map_release);
+ }
reset_vma_resv_huge_pages(vma);
}