diff options
| author | Muchun Song <songmuchun@bytedance.com> | 2021-02-04 18:32:10 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-02-10 09:21:08 +0100 |
| commit | 532574ae2586940729419253fd2defd9c9880490 (patch) | |
| tree | 7fea66ca6c05543475e3f2dce679cf3dc6bbb9e7 /mm | |
| parent | db510d8f98c38a953ae5d3b51b01f435740729b4 (diff) | |
| download | linux-rt-532574ae2586940729419253fd2defd9c9880490.tar.gz | |
mm: hugetlb: fix a race between isolating and freeing page
commit 0eb2df2b5629794020f75e94655e1994af63f0d4 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
| -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 9054e443e1d2..2f9e4bc1c2a7 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4979,9 +4979,9 @@ 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; } |