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From: Andrew Morton <akpm@linux-foundation.org>
To: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Cc: linux-kernel@vger.kernel.org,
	Nicolas Geoffray <ngeoffray@google.com>,
	kernel-team@android.com, Hugh Dickins <hughd@google.com>,
	linux-kselftest@vger.kernel.org, linux-mm@kvack.org,
	Shuah Khan <shuah@kernel.org>
Subject: Re: [PATCH 1/2] memfd: Fix COW issue on MAP_PRIVATE and F_SEAL_FUTURE_WRITE mappings
Date: Thu, 7 Nov 2019 17:00:23 -0800	[thread overview]
Message-ID: <20191107170023.0695732bb67eb80acd4caee5@linux-foundation.org> (raw)
In-Reply-To: <20191107195355.80608-1-joel@joelfernandes.org>

On Thu,  7 Nov 2019 14:53:54 -0500 "Joel Fernandes (Google)" <joel@joelfernandes.org> wrote:

> F_SEAL_FUTURE_WRITE has unexpected behavior when used with MAP_PRIVATE:
> A private mapping created after the memfd file that gets sealed with
> F_SEAL_FUTURE_WRITE loses the copy-on-write at fork behavior, meaning
> children and parent share the same memory, even though the mapping is
> private.

That sounds fairly serious.  Should this be backported into -stable kernels?

  parent reply	other threads:[~2019-11-08  1:00 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-07 19:53 Joel Fernandes (Google)
2019-11-07 19:53 ` [PATCH 2/2] memfd: Add test for COW " Joel Fernandes (Google)
2019-11-08  1:00 ` Andrew Morton [this message]
2019-11-08  2:06   ` [PATCH 1/2] memfd: Fix COW issue " Joel Fernandes
2019-11-08  3:25     ` Andrew Morton
2019-11-08  6:37     ` Greg KH
2019-11-08 15:34       ` Joel Fernandes
2019-11-08  6:33 ` Christoph Hellwig
2019-11-08 15:35   ` Joel Fernandes

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