From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, almasrymina@google.com,
linmiaohe@huawei.com, linux-mm@kvack.org, mhocko@suse.com,
mike.kravetz@oracle.com, minhquangbui99@gmail.com,
mm-commits@vger.kernel.org, songmuchun@bytedance.com,
torvalds@linux-foundation.org
Subject: [patch 09/15] hugetlb: fix hugetlb cgroup refcounting during mremap
Date: Fri, 19 Nov 2021 16:43:40 -0800 [thread overview]
Message-ID: <20211120004340.S1hmWsXgy%akpm@linux-foundation.org> (raw)
In-Reply-To: <20211119164248.50feee07c5d2cc6cc4addf97@linux-foundation.org>
From: Bui Quang Minh <minhquangbui99@gmail.com>
Subject: 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>
---
include/linux/hugetlb_cgroup.h | 12 ++++++++++++
mm/hugetlb.c | 4 +++-
2 files changed, 15 insertions(+), 1 deletion(-)
--- a/include/linux/hugetlb_cgroup.h~hugetlb-fix-hugetlb-cgroup-refcounting-during-mremap
+++ a/include/linux/hugetlb_cgroup.h
@@ -128,6 +128,13 @@ static inline void resv_map_dup_hugetlb_
css_get(resv_map->css);
}
+static inline void resv_map_put_hugetlb_cgroup_uncharge_info(
+ struct resv_map *resv_map)
+{
+ if (resv_map->css)
+ css_put(resv_map->css);
+}
+
extern int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
struct hugetlb_cgroup **ptr);
extern int hugetlb_cgroup_charge_cgroup_rsvd(int idx, unsigned long nr_pages,
@@ -210,6 +217,11 @@ static inline void resv_map_dup_hugetlb_
struct resv_map *resv_map)
{
}
+
+static inline void resv_map_put_hugetlb_cgroup_uncharge_info(
+ struct resv_map *resv_map)
+{
+}
static inline int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
struct hugetlb_cgroup **ptr)
--- a/mm/hugetlb.c~hugetlb-fix-hugetlb-cgroup-refcounting-during-mremap
+++ a/mm/hugetlb.c
@@ -1037,8 +1037,10 @@ void clear_vma_resv_huge_pages(struct vm
*/
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);
}
_
next prev parent reply other threads:[~2021-11-20 0:43 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-20 0:42 incoming Andrew Morton
2021-11-20 0:43 ` [patch 01/15] mm/swap.c:put_pages_list(): reinitialise the page list Andrew Morton
2021-11-20 0:43 ` [patch 02/15] ipc: WARN if trying to remove ipc object which is absent Andrew Morton
2021-11-20 0:43 ` [patch 03/15] shm: extend forced shm destroy to support objects from several IPC nses Andrew Morton
2021-11-20 0:43 ` [patch 04/15] mm: emit the "free" trace report before freeing memory in kmem_cache_free() Andrew Morton
2021-11-20 0:43 ` [patch 05/15] hexagon: export raw I/O routines for modules Andrew Morton
2021-11-20 0:43 ` [patch 06/15] hexagon: clean up timer-regs.h Andrew Morton
2021-11-20 0:43 ` [patch 07/15] hexagon: ignore vmlinux.lds Andrew Morton
2021-11-20 0:43 ` [patch 08/15] mm: kmemleak: slob: respect SLAB_NOLEAKTRACE flag Andrew Morton
2021-11-20 0:43 ` Andrew Morton [this message]
2021-11-20 0:43 ` [patch 10/15] hugetlb, userfaultfd: fix reservation restore on userfaultfd error Andrew Morton
2021-11-20 0:43 ` [patch 11/15] kasan: test: silence intentional read overflow warnings Andrew Morton
2021-11-20 0:43 ` [patch 12/15] mm/damon/dbgfs: use '__GFP_NOWARN' for user-specified size buffer allocation Andrew Morton
2021-11-20 0:43 ` [patch 13/15] mm/damon/dbgfs: fix missed use of damon_dbgfs_lock Andrew Morton
2021-11-20 0:43 ` [patch 14/15] kmap_local: don't assume kmap PTEs are linear arrays in memory Andrew Morton
2021-11-20 0:43 ` [patch 15/15] proc/vmcore: fix clearing user buffer by properly using clear_user() Andrew Morton
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