From: Muchun Song <muchun.song@linux.dev>
To: Miaohe Lin <linmiaohe@huawei.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Muchun Song <songmuchun@bytedance.com>,
Linux MM <linux-mm@kvack.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/6] mm: hugetlb_vmemmap: add missing smp_wmb() before set_pte_at()
Date: Mon, 22 Aug 2022 18:23:27 +0800 [thread overview]
Message-ID: <F8381885-8B9F-405B-A860-AFB8A675D5A7@linux.dev> (raw)
In-Reply-To: <bfb89f55-a618-4b36-7075-654922a8ddaa@huawei.com>
> On Aug 22, 2022, at 16:45, Miaohe Lin <linmiaohe@huawei.com> wrote:
>
> On 2022/8/20 16:12, Muchun Song wrote:
>>
>>
>>> On Aug 16, 2022, at 21:05, Miaohe Lin <linmiaohe@huawei.com> wrote:
>>>
>>> The memory barrier smp_wmb() is needed to make sure that preceding stores
>>> to the page contents become visible before the below set_pte_at() write.
>>
>> I found another place where is a similar case. See kasan_populate_vmalloc_pte() in
>> mm/kasan/shadow.c.
>
> Thanks for your report.
>
>>
>> Should we fix it as well?
>
> I'm not familiar with kasan yet, but I think memory barrier is needed here or memory corrupt
> can't be detected until the contents are visible. smp_mb__after_atomic before set_pte_at should
> be enough? What's your opinion?
I didn’t see any atomic operation between set_pte_at() and memset(), I don’t think
smp_mb__after_atomic() is feasible if we really need to insert a barrier. I suggest
you to send a RFC patch to KASAN maintainers, they are more familiar with this than
us.
Thanks.
>
> Thanks,
> Miaohe Lin
>
>
next prev parent reply other threads:[~2022-08-22 10:23 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-16 13:05 [PATCH 0/6] A few fixup patches for hugetlb Miaohe Lin
2022-08-16 13:05 ` [PATCH 1/6] mm/hugetlb: fix incorrect update of max_huge_pages Miaohe Lin
2022-08-16 22:52 ` Mike Kravetz
2022-08-16 23:20 ` Andrew Morton
2022-08-16 23:34 ` Mike Kravetz
2022-08-17 1:53 ` Miaohe Lin
2022-08-17 2:28 ` Muchun Song
2022-08-16 13:05 ` [PATCH 2/6] mm/hugetlb: fix WARN_ON(!kobj) in sysfs_create_group() Miaohe Lin
2022-08-16 22:55 ` Mike Kravetz
2022-08-17 2:31 ` Muchun Song
2022-08-17 2:39 ` Miaohe Lin
2022-08-16 13:05 ` [PATCH 3/6] mm/hugetlb: fix missing call to restore_reserve_on_error() Miaohe Lin
2022-08-16 23:31 ` Mike Kravetz
2022-08-17 1:59 ` Miaohe Lin
2022-08-16 13:05 ` [PATCH 4/6] mm: hugetlb_vmemmap: add missing smp_wmb() before set_pte_at() Miaohe Lin
2022-08-17 2:53 ` Muchun Song
2022-08-17 8:41 ` Miaohe Lin
2022-08-17 9:13 ` Yin, Fengwei
2022-08-17 11:21 ` Muchun Song
2022-08-18 1:14 ` Yin, Fengwei
2022-08-18 1:55 ` Miaohe Lin
2022-08-18 2:00 ` Yin, Fengwei
2022-08-18 2:47 ` Muchun Song
2022-08-18 7:52 ` Miaohe Lin
2022-08-18 7:59 ` Muchun Song
2022-08-18 8:32 ` Yin, Fengwei
2022-08-18 8:40 ` Muchun Song
2022-08-18 8:54 ` Yin, Fengwei
2022-08-18 9:18 ` Muchun Song
2022-08-18 12:58 ` Miaohe Lin
2022-08-18 23:53 ` Yin, Fengwei
2022-08-19 3:19 ` Muchun Song
2022-08-19 7:26 ` Miaohe Lin
2022-08-18 1:15 ` Yin, Fengwei
2022-08-20 8:12 ` Muchun Song
2022-08-22 8:45 ` Miaohe Lin
2022-08-22 10:23 ` Muchun Song [this message]
2022-08-23 1:42 ` Miaohe Lin
2022-08-16 13:05 ` [PATCH 5/6] mm/hugetlb: fix sysfs group leak in hugetlb_unregister_node() Miaohe Lin
2022-08-17 9:41 ` Yin, Fengwei
2022-08-18 1:00 ` Yin, Fengwei
2022-08-18 1:12 ` Yin, Fengwei
2022-08-16 13:05 ` [PATCH 6/6] mm/hugetlb: make detecting shared pte more reliable Miaohe Lin
2022-08-17 23:56 ` Mike Kravetz
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