From: Michal Hocko <mhocko@suse.com>
To: Muchun Song <songmuchun@bytedance.com>
Cc: mike.kravetz@oracle.com, akpm@linux-foundation.org,
n-horiguchi@ah.jp.nec.com, ak@linux.intel.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 5/6] mm: hugetlb: fix a race between isolating and freeing page
Date: Wed, 6 Jan 2021 18:10:48 +0100 [thread overview]
Message-ID: <20210106171048.GV13207@dhcp22.suse.cz> (raw)
In-Reply-To: <20210106084739.63318-6-songmuchun@bytedance.com>
On Wed 06-01-21 16:47:38, Muchun Song wrote:
> 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.
>
> 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>
Thanks!
> ---
> mm/hugetlb.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index bf02e81e3953..67200dd25b1d 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -5587,9 +5587,9 @@ 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;
> }
> --
> 2.11.0
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2021-01-06 17:11 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-06 8:47 [PATCH v2 0/6] Fix some bugs about HugeTLB code Muchun Song
2021-01-06 8:47 ` [PATCH v2 1/6] mm: migrate: do not migrate HugeTLB page whose refcount is one Muchun Song
2021-01-06 16:13 ` Michal Hocko
2021-01-07 2:52 ` [External] " Muchun Song
2021-01-07 11:16 ` Michal Hocko
2021-01-07 11:24 ` Muchun Song
2021-01-07 11:48 ` Michal Hocko
2021-01-06 8:47 ` [PATCH v2 2/6] mm: hugetlbfs: fix cannot migrate the fallocated HugeTLB page Muchun Song
2021-01-06 16:35 ` Michal Hocko
2021-01-06 19:30 ` Mike Kravetz
2021-01-06 20:02 ` Michal Hocko
2021-01-06 21:07 ` Mike Kravetz
2021-01-07 8:36 ` Michal Hocko
2021-01-07 2:58 ` [External] " Muchun Song
2021-01-06 8:47 ` [PATCH v2 3/6] mm: hugetlb: fix a race between freeing and dissolving the page Muchun Song
2021-01-06 16:56 ` Michal Hocko
2021-01-06 20:58 ` Mike Kravetz
2021-01-07 3:08 ` [External] " Muchun Song
2021-01-07 8:40 ` Michal Hocko
2021-01-08 0:52 ` Mike Kravetz
2021-01-08 8:28 ` Michal Hocko
2021-01-07 5:39 ` [External] " Muchun Song
2021-01-07 8:41 ` Michal Hocko
2021-01-07 8:53 ` Muchun Song
2021-01-07 11:18 ` Michal Hocko
2021-01-07 11:38 ` Muchun Song
2021-01-07 12:38 ` Michal Hocko
2021-01-07 12:59 ` Muchun Song
2021-01-07 14:11 ` Michal Hocko
2021-01-07 15:11 ` Muchun Song
2021-01-08 1:06 ` Mike Kravetz
2021-01-08 2:38 ` Muchun Song
2021-01-08 8:43 ` Michal Hocko
2021-01-08 9:01 ` Muchun Song
2021-01-08 9:31 ` Michal Hocko
2021-01-08 10:08 ` Muchun Song
2021-01-08 11:44 ` Michal Hocko
2021-01-08 11:52 ` Muchun Song
2021-01-08 12:04 ` Michal Hocko
2021-01-08 12:24 ` Muchun Song
2021-01-06 8:47 ` [PATCH v2 4/6] mm: hugetlb: add return -EAGAIN for dissolve_free_huge_page Muchun Song
2021-01-06 17:07 ` Michal Hocko
2021-01-07 3:11 ` [External] " Muchun Song
2021-01-07 8:39 ` Michal Hocko
2021-01-07 9:01 ` Muchun Song
2021-01-07 11:22 ` Michal Hocko
2021-01-06 8:47 ` [PATCH v2 5/6] mm: hugetlb: fix a race between isolating and freeing page Muchun Song
2021-01-06 17:10 ` Michal Hocko [this message]
2021-01-06 8:47 ` [PATCH v2 6/6] mm: hugetlb: remove VM_BUG_ON_PAGE from page_huge_active Muchun Song
2021-01-06 17:16 ` Michal Hocko
2021-01-08 22:24 ` Mike Kravetz
2021-01-09 4:07 ` [External] " Muchun Song
2021-01-07 9:30 ` [PATCH v2 0/6] Fix some bugs about HugeTLB code David Hildenbrand
2021-01-07 9:40 ` [External] " Muchun Song
2021-01-07 10:10 ` David Hildenbrand
2021-01-07 10:16 ` Muchun Song
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