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From: valdis.kletnieks@vt.edu
To: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Cc: linux-kernel@vger.kernel.org, kernel-team@android.com,
	jreck@google.com, john.stultz@linaro.org, tkjos@google.com,
	gregkh@linuxfoundation.org, hch@infradead.org,
	Al Viro <viro@zeniv.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	dancol@google.com, "J. Bruce Fields" <bfields@fieldses.org>,
	Jeff Layton <jlayton@kernel.org>,
	linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-mm@kvack.org, marcandre.lureau@redhat.com,
	Mike Kravetz <mike.kravetz@oracle.com>,
	minchan@kernel.org, Shuah Khan <shuah@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v3 1/2] mm: Add an F_SEAL_FUTURE_WRITE seal to memfd
Date: Fri, 19 Oct 2018 13:32:02 -0400	[thread overview]
Message-ID: <42922.1539970322@turing-police.cc.vt.edu> (raw)
In-Reply-To: <20181018065908.254389-1-joel@joelfernandes.org>

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On Wed, 17 Oct 2018 23:59:07 -0700, "Joel Fernandes (Google)" said:
> This usecase cannot be implemented with the existing F_SEAL_WRITE seal.
> To support the usecase, this patch adds a new F_SEAL_FUTURE_WRITE seal
> which prevents any future mmap and write syscalls from succeeding while
> keeping the existing mmap active. The following program shows the seal
> working in action:

What is supposed to happen if some other process has an already existing R/W
mmap of the region?  (For that matter, the test program doesn't seem to
actually test that the existing mmap region remains writable?)


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  parent reply	other threads:[~2018-10-19 17:32 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-18  6:59 Joel Fernandes (Google)
2018-10-18  6:59 ` [PATCH v3 2/2] selftests/memfd: Add tests for F_SEAL_FS_WRITE seal Joel Fernandes (Google)
2018-10-18  7:08   ` Joel Fernandes
2018-10-19 17:32 ` valdis.kletnieks [this message]
2018-10-19 17:57   ` [PATCH v3 1/2] mm: Add an F_SEAL_FUTURE_WRITE seal to memfd Joel Fernandes
2018-10-19 18:49     ` valdis.kletnieks
2018-10-19 19:32       ` Joel Fernandes
2018-10-22 23:49 ` Joel Fernandes

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