diff options
| author | Miaohe Lin <linmiaohe@huawei.com> | 2022-04-29 09:16:08 +0300 |
|---|---|---|
| committer | akpm <akpm@linux-foundation.org> | 2022-04-29 09:16:08 +0300 |
| commit | 4cd614841c06338a087769ee3cfa96718784d1f5 (patch) | |
| tree | ee09e7c06e2513b977739324f12cc9ee7d88f263 /mm/migrate.c | |
| parent | 3f26c88bd66cd8ab1731763c68df7fe23a7671c0 (diff) | |
| download | linux-4cd614841c06338a087769ee3cfa96718784d1f5.tar.xz | |
mm/migration: fix possible do_pages_stat_array racing with memory offline
When follow_page peeks a page, the page could be migrated and then be
offlined while it's still being used by the do_pages_stat_array(). Use
FOLL_GET to hold the page refcnt to fix this potential race.
Link: https://lkml.kernel.org/r/20220318111709.60311-12-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/migrate.c')
| -rw-r--r-- | mm/migrate.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index cb3fa7c24081..35f6416d2953 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1796,13 +1796,18 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, goto set_status; /* FOLL_DUMP to ignore special (like zero) pages */ - page = follow_page(vma, addr, FOLL_DUMP); + page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); err = PTR_ERR(page); if (IS_ERR(page)) goto set_status; - err = page ? page_to_nid(page) : -ENOENT; + if (page) { + err = page_to_nid(page); + put_page(page); + } else { + err = -ENOENT; + } set_status: *status = err; |