From: David Hildenbrand <david@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Helge Deller <deller@gmx.de>, Daniel Vetter <daniel@ffwll.ch>,
Matthew Wilcox <willy@infradead.org>,
linux-mm@kvack.org, Jonathan Corbet <corbet@lwn.net>
Subject: Re: [PATCH 1/4] fs/proc/task_mmu: use folio API in pte_is_pinned()
Date: Wed, 26 Jun 2024 06:57:44 +0200 [thread overview]
Message-ID: <817fe841-a071-43c4-9df5-806f6ec351e0@redhat.com> (raw)
In-Reply-To: <20240625153823.b59bbee937fc3cde28bddbab@linux-foundation.org>
On 26.06.24 00:38, Andrew Morton wrote:
> On Wed, 5 Jun 2024 09:30:59 +0800 Kefeng Wang <wangkefeng.wang@huawei.com> wrote:
>
>>> protection to catch successive writes (mprotect, uffd-wp) -- and
>>> they all
>>> face the same issue regarding R/W access via GUP (FOLL_PIN and
>>> FOLL_GET).
>>> User space better be aware that using read-protection to catch
>>> writes to
>>> a page can miss writes via GUP. Softdirt tracking cannot reliably
>>> catch
>>> modifications via GUP after clearing softdirty and returning to user
>>> space.
>>>
>>> But I understand if you want to be careful :) So I might send that patch
>>> out at
>>> some point myself ...
>>>
>>
>> Thank for your detail explanation, let's wait it out.
>
> Did we wait long enough? Should we move ahead with this change
> or should we drop it and have another run at it?
The change is fine, we will revisit removing this code (instead of
cleaning it up) separately.
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2024-06-26 4:57 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-04 11:48 [PATCH 0/4] mm: remove page_maybe_dma_pinned() and page_mkclean() Kefeng Wang
2024-06-04 11:48 ` [PATCH 1/4] fs/proc/task_mmu: use folio API in pte_is_pinned() Kefeng Wang
2024-06-04 11:51 ` David Hildenbrand
2024-06-04 14:26 ` Kefeng Wang
[not found] ` <f466aae2-9a3e-4081-b2d8-fa5930b8bc29@redhat.com>
2024-06-05 1:30 ` Kefeng Wang
2024-06-25 22:38 ` Andrew Morton
2024-06-26 4:57 ` David Hildenbrand [this message]
2024-06-04 11:48 ` [PATCH 2/4] mm: remove page_maybe_dma_pinned() Kefeng Wang
2024-06-04 11:48 ` [PATCH 3/4] fb_defio: use a folio in fb_deferred_io_work() Kefeng Wang
2024-06-04 11:53 ` David Hildenbrand
2024-06-04 11:48 ` [PATCH 4/4] mm: remove page_mkclean() Kefeng Wang
2024-06-07 6:46 ` [PATCH] pin_user_pages: fix underline length Kefeng Wang
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