From: Michal Hocko <mhocko@suse.cz>
To: zhong jiang <zhongjiang@huawei.com>
Cc: akpm@linux-foundation.org, vbabka@suse.cz, rientjes@google.com,
qiuxishi@huawei.com, linux-mm@kvack.org
Subject: Re: [PATCH] mm/hugetlb: fix race when migrate pages.
Date: Tue, 19 Jul 2016 13:59:53 +0200 [thread overview]
Message-ID: <20160719115952.GI9486@dhcp22.suse.cz> (raw)
In-Reply-To: <578E126A.7080001@huawei.com>
On Tue 19-07-16 19:43:38, zhong jiang wrote:
[...]
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 6384dfd..baba196 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -4213,7 +4213,7 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
> struct vm_area_struct *svma;
> unsigned long saddr;
> pte_t *spte = NULL;
> - pte_t *pte;
> + pte_t *pte, entry;
> spinlock_t *ptl;
>
> if (!vma_shareable(vma, addr))
> @@ -4240,6 +4240,11 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
>
> ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte);
> spin_lock(ptl);
> + entry = huge_ptep_get(spte);
> + if (is_hugetlb_entry_migration(entry) ||
> + is_hugetlb_entry_hwpoisoned(entry)) {
> + goto end;
> + }
> if (pud_none(*pud)) {
> pud_populate(mm, pud,
> (pmd_t *)((unsigned long)spte & PAGE_MASK));
> @@ -4247,6 +4252,7 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
> put_page(virt_to_page(spte));
> mm_dec_nr_pmds(mm);
> }
> +end:
out_unlock:
would be more readable. Could you retest the patch, respin the changelog
to explain what, why and how to fix it and repost again, please?
> spin_unlock(ptl);
> out:
> pte = (pte_t *)pmd_alloc(mm, pud, addr);
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2016-07-19 11:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-19 2:59 [PATCH] mm/hugetlb: fix race when migrate pages zhongjiang
2016-07-19 9:17 ` Michal Hocko
2016-07-19 9:52 ` zhong jiang
2016-07-19 11:10 ` Michal Hocko
2016-07-19 11:31 ` zhong jiang
2016-07-19 11:43 ` zhong jiang
2016-07-19 11:59 ` Michal Hocko [this message]
2016-07-19 12:04 ` zhong jiang
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