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From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jeff Xu <jeffxu@chromium.org>, Jeff Xu <jeffxu@google.com>,
	Jonathan Corbet <corbet@lwn.net>,
	akpm@linux-foundation.org, keescook@chromium.org,
	jannh@google.com, sroettger@google.com, willy@infradead.org,
	gregkh@linuxfoundation.org, usama.anjum@collabora.com,
	rdunlap@infradead.org, jorgelo@chromium.org, groeck@chromium.org,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-mm@kvack.org, pedro.falcato@gmail.com,
	dave.hansen@intel.com, linux-hardening@vger.kernel.org
Subject: Re: [PATCH v8 0/4] Introduce mseal
Date: Fri, 2 Feb 2024 16:18:07 -0500	[thread overview]
Message-ID: <20240202211807.6sca4ppezma7cyev@revolver> (raw)
In-Reply-To: <CAHk-=wjNXcqDVxDBJW8hEVpHHAE0odJEf63+oigabtpU6GoCBg@mail.gmail.com>

* Linus Torvalds <torvalds@linux-foundation.org> [240202 15:37]:
> On Fri, 2 Feb 2024 at 11:32, Theo de Raadt <deraadt@openbsd.org> wrote:
> >
> > Unix system calls must be atomic.
> >
> > They either return an error, and that is a promise they made no changes.
> 
> That's actually not true, and never has been.

...

> 
> In the specific case of mseal(), I suspect there are very few reasons
> ever *not* to be atomic, so in this particular context atomicity is
> likely always something that should be guaranteed. But I just wanted
> to point out that it's most definitely not a black-and-white issue in
> the general case.

There will be a larger performance cost to checking up front without
allowing the partial completion.  I don't expect these to be high, but
it's something to keep in mind if we are okay with the flexibility and
less atomic operation.

Thanks,
Liam

  parent reply	other threads:[~2024-02-02 21:18 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-31 17:50 [PATCH v8 0/4] Introduce mseal jeffxu
2024-01-31 17:50 ` [PATCH v8 1/4] mseal: Wire up mseal syscall jeffxu
2024-01-31 17:50 ` [PATCH v8 2/4] mseal: add " jeffxu
2024-02-01 23:11   ` Eric Biggers
2024-02-02  3:30     ` Jeff Xu
2024-02-02  3:54       ` Theo de Raadt
2024-02-02  4:03         ` Jeff Xu
2024-02-02  4:10           ` Theo de Raadt
2024-02-02  4:22             ` Jeff Xu
2024-01-31 17:50 ` [PATCH v8 3/4] selftest mm/mseal memory sealing jeffxu
2024-01-31 17:50 ` [PATCH v8 4/4] mseal:add documentation jeffxu
2024-01-31 19:34 ` [PATCH v8 0/4] Introduce mseal Liam R. Howlett
2024-02-01  1:27   ` Jeff Xu
2024-02-01  1:46     ` Theo de Raadt
2024-02-01 16:56       ` Bird, Tim
2024-02-01  1:55     ` Theo de Raadt
2024-02-01 20:45     ` Liam R. Howlett
2024-02-01 22:24       ` Theo de Raadt
2024-02-02  1:06         ` Greg KH
2024-02-02  3:24           ` Jeff Xu
2024-02-02  3:29             ` Linus Torvalds
2024-02-02  3:46               ` Jeff Xu
2024-02-02 15:18             ` Greg KH
2024-02-01 22:37       ` Jeff Xu
2024-02-01 22:54         ` Theo de Raadt
2024-02-01 23:15           ` Linus Torvalds
2024-02-01 23:43             ` Theo de Raadt
2024-02-02  0:26             ` Theo de Raadt
2024-02-02  3:20             ` Jeff Xu
2024-02-02  4:05               ` Theo de Raadt
2024-02-02  4:54                 ` Jeff Xu
2024-02-02  5:00                   ` Theo de Raadt
2024-02-02 17:58                     ` Jeff Xu
2024-02-02 18:51                       ` Pedro Falcato
2024-02-02 21:20                         ` Jeff Xu
2024-02-04 19:39                         ` David Laight
2024-02-02 17:05             ` Theo de Raadt
2024-02-02 21:02               ` Jeff Xu
2024-02-02  3:14       ` Jeff Xu
2024-02-02 15:13         ` Liam R. Howlett
2024-02-02 17:24           ` Jeff Xu
2024-02-02 19:21             ` Liam R. Howlett
2024-02-02 19:32               ` Theo de Raadt
2024-02-02 20:36                 ` Linus Torvalds
2024-02-02 20:57                   ` Jeff Xu
2024-02-02 21:18                   ` Liam R. Howlett [this message]
2024-02-02 23:36                     ` Linus Torvalds
2024-02-03  4:45                       ` Liam R. Howlett
2024-02-05 22:13                         ` Suren Baghdasaryan
2024-02-02 20:14               ` Jeff Xu

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