diff options
| author | Muchun Song <songmuchun@bytedance.com> | 2021-02-04 18:32:10 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-02-05 11:03:47 -0800 |
| commit | 0eb2df2b5629794020f75e94655e1994af63f0d4 (patch) | |
| tree | 81ec3673173dc7994aa56396b5800a5c4ad267d6 | |
| parent | 7ffddd499ba6122b1a07828f023d1d67629aa017 (diff) | |
| download | linux-0eb2df2b5629794020f75e94655e1994af63f0d4.tar.bz2 | |
mm: hugetlb: fix a race between isolating and freeing page
There is a race between isolate_huge_page() and __free_huge_page().
CPU0: CPU1:
if (PageHuge(page))
put_page(page)
__free_huge_page(page)
spin_lock(&hugetlb_lock)
update_and_free_page(page)
set_compound_page_dtor(page,
NULL_COMPOUND_DTOR)
spin_unlock(&hugetlb_lock)
isolate_huge_page(page)
// trigger BUG_ON
VM_BUG_ON_PAGE(!PageHead(page), page)
spin_lock(&hugetlb_lock)
page_huge_active(page)
// trigger BUG_ON
VM_BUG_ON_PAGE(!PageHuge(page), page)
spin_unlock(&hugetlb_lock)
When we isolate a HugeTLB page on CPU0. Meanwhile, we free it to the
buddy allocator on CPU1. Then, we can trigger a BUG_ON on CPU0, because
it is already freed to the buddy allocator.
Link: https://lkml.kernel.org/r/20210115124942.46403-5-songmuchun@bytedance.com
Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/hugetlb.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index c6ee3c28a04e..90e03c3000c5 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5594,9 +5594,9 @@ bool isolate_huge_page(struct page *page, struct list_head *list) { bool ret = true; - VM_BUG_ON_PAGE(!PageHead(page), page); spin_lock(&hugetlb_lock); - if (!page_huge_active(page) || !get_page_unless_zero(page)) { + if (!PageHeadHuge(page) || !page_huge_active(page) || + !get_page_unless_zero(page)) { ret = false; goto unlock; } |