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From: Ryan Roberts <ryan.roberts@arm.com>
To: Yu Zhao <yuzhao@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	SeongJae Park <sj@kernel.org>,
	Christoph Hellwig <hch@infradead.org>,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Lorenzo Stoakes <lstoakes@gmail.com>,
	Uladzislau Rezki <urezki@gmail.com>, Zi Yan <ziy@nvidia.com>,
	Mike Rapoport <rppt@kernel.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Subject: Re: [PATCH v3 2/4] mm/damon/ops-common: atomically test and clear young on ptes and pmds
Date: Fri, 2 Jun 2023 18:14:25 +0100	[thread overview]
Message-ID: <640f81aa-035e-9f42-c848-096e4c9e014c@arm.com> (raw)
In-Reply-To: <CAOUHufb5R_+eMxM28WWxXubPzUO4+c_1UHoXVAcWsKEyG1ndAQ@mail.gmail.com>

On 02/06/2023 17:35, Yu Zhao wrote:
> On Fri, Jun 2, 2023 at 3:30 AM Ryan Roberts <ryan.roberts@arm.com> wrote:
>> It is racy to non-atomically read a pte, then clear the young bit, then
>> write it back as this could discard dirty information. Further, it is
>> bad practice to directly set a pte entry within a table. Instead
>> clearing young must go through the arch-provided helper,
>> ptep_test_and_clear_young() to ensure it is modified atomically and to
>> give the arch code visibility and allow it to check (and potentially
>> modify) the operation.
>> Fixes: 3f49584b262c ("mm/damon: implement primitives for the virtual memory address spaces").
> Just to double check: was "Cc: stable@vger.kernel.org" overlooked or
> deemed unnecessary?

It was overlooked - incompetance strikes again! I was intending to cc the whole
series. What's the best way to fix this? Can I just add stable in cc on reply to
the cover letter or will I have to resend the lot?

>> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
>> Reviewed-by: Zi Yan <ziy@nvidia.com>
>> Reviewed-by: SeongJae Park <sj@kernel.org>
>> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>

  reply	other threads:[~2023-06-02 17:14 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-02  9:29 [PATCH v3 0/4] Fixes for pte encapsulation bypasses Ryan Roberts
2023-06-02  9:29 ` [PATCH v3 1/4] mm: vmalloc must set pte via arch code Ryan Roberts
2023-06-02  9:29 ` [PATCH v3 2/4] mm/damon/ops-common: atomically test and clear young on ptes and pmds Ryan Roberts
2023-06-02 16:35   ` Yu Zhao
2023-06-02 17:14     ` Ryan Roberts [this message]
2023-06-02 17:35       ` Yu Zhao
2023-06-02 19:15       ` SeongJae Park
2023-06-02 21:43         ` SeongJae Park
2023-06-03 18:20           ` Ryan Roberts
2023-06-02  9:29 ` [PATCH v3 3/4] mm/damon/ops-common: Refactor to use {pte|pmd}p_clear_young_notify() Ryan Roberts
2023-06-02 16:28   ` Yu Zhao
2023-06-02 21:54   ` SeongJae Park
2023-06-02  9:29 ` [PATCH v3 4/4] mm: Fix failure to unmap pte on highmem systems Ryan Roberts

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