From: Qian Cai <cai@lca.pw>
To: "Longpeng(Mike)" <longpeng2@huawei.com>
Cc: akpm@linux-foundation.org, mike.kravetz@oracle.com,
kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org,
arei.gonglei@huawei.com, weidong.huang@huawei.com,
weifuqiang@huawei.com, kvm@vger.kernel.org, linux-mm@kvack.org,
Matthew Wilcox <willy@infradead.org>,
Sean Christopherson <sean.j.christopherson@intel.com>,
stable@vger.kernel.org
Subject: Re: [PATCH v2] mm/hugetlb: fix a addressing exception caused by huge_pte_offset()
Date: Sat, 22 Feb 2020 00:23:44 -0500 [thread overview]
Message-ID: <C4ED630A-FAD8-4998-A0A3-9C36F3303379@lca.pw> (raw)
> On Feb 21, 2020, at 10:34 PM, Longpeng(Mike) <longpeng2@huawei.com> wrote:
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index dd8737a..90daf37 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -4910,28 +4910,30 @@ pte_t *huge_pte_offset(struct mm_struct *mm,
> {
> pgd_t *pgd;
> p4d_t *p4d;
> - pud_t *pud;
> - pmd_t *pmd;
> + pud_t *pud, pud_entry;
> + pmd_t *pmd, pmd_entry;
>
> pgd = pgd_offset(mm, addr);
> - if (!pgd_present(*pgd))
> + if (!pgd_present(READ_ONCE(*pgd)))
> return NULL;
> p4d = p4d_offset(pgd, addr);
> - if (!p4d_present(*p4d))
> + if (!p4d_present(READ_ONCE(*p4d)))
> return NULL;
What’s the point of READ_ONCE() on those two places?
next reply other threads:[~2020-02-22 5:23 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-22 5:23 Qian Cai [this message]
2020-02-22 6:33 ` [PATCH v2] mm/hugetlb: fix a addressing exception caused by huge_pte_offset() Longpeng (Mike)
2020-02-22 11:50 ` Qian Cai
2020-02-22 17:02 ` Matthew Wilcox
2020-02-23 1:24 ` Longpeng (Mike)
2020-02-27 21:41 ` Mike Kravetz
2020-03-21 22:46 ` Andrew Morton
-- strict thread matches above, loose matches on Subject: below --
2020-02-22 3:33 Longpeng(Mike)
2020-03-21 23:38 ` Mike Kravetz
2020-03-23 2:03 ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2020-03-23 2:54 ` Mike Kravetz
2020-03-23 3:43 ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2020-03-23 14:40 ` Sean Christopherson
2020-03-23 16:44 ` Jason Gunthorpe
2020-03-23 16:09 ` Jason Gunthorpe
2020-03-23 17:27 ` Mike Kravetz
2020-03-23 18:07 ` Jason Gunthorpe
2020-03-23 20:35 ` Mike Kravetz
2020-03-23 22:52 ` Jason Gunthorpe
2020-03-24 2:37 ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2020-03-24 11:55 ` Jason Gunthorpe
2020-03-24 15:25 ` Mike Kravetz
2020-03-24 15:55 ` Jason Gunthorpe
2020-03-24 16:19 ` Mike Kravetz
2020-03-24 17:59 ` Jason Gunthorpe
2020-03-24 19:47 ` Mike Kravetz
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