From: Matt Whitlock <kernel@mattwhitlock.name>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: David Howells <dhowells@redhat.com>, <netdev@vger.kernel.org>,
Matthew Wilcox <willy@infradead.org>,
Dave Chinner <david@fromorbit.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Jens Axboe <axboe@kernel.dk>, <linux-fsdevel@kvack.org>,
<linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@lst.de>, <linux-fsdevel@vger.kernel.org>
Subject: Re: [RFC PATCH 1/4] splice: Fix corruption of spliced data after splice() returns
Date: Wed, 19 Jul 2023 13:59:13 -0400 [thread overview]
Message-ID: <c634a18e-9f2b-4746-bd8f-aa1d41e6ddf7@mattwhitlock.name> (raw)
In-Reply-To: <CAJfpegsJuvXJDcXpo9T19Gw0tDuvyOJdv44Y2bt04MEf1JLxGg@mail.gmail.com>
On Wednesday, 19 July 2023 06:17:51 EDT, Miklos Szeredi wrote:
> On Thu, 29 Jun 2023 at 17:56, David Howells <dhowells@redhat.com> wrote:
>>
>> Splicing data from, say, a file into a pipe currently leaves the source
>> pages in the pipe after splice() returns - but this means that those pages
>> can be subsequently modified by shared-writable mmap(), write(),
>> fallocate(), etc. before they're consumed.
>
> What is this trying to fix? The above behavior is well known, so
> it's not likely to be a problem.
Respectfully, it's not well-known, as it's not documented. If the splice(2)
man page had mentioned that pages can be mutated after they're already
ostensibly at rest in the output pipe buffer, then my nightly backups
wouldn't have been incurring corruption silently for many months.
next prev parent reply other threads:[~2023-07-19 17:59 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-29 15:54 [RFC PATCH 0/4] splice: Fix corruption in data spliced to pipe David Howells
2023-06-29 15:54 ` [RFC PATCH 1/4] splice: Fix corruption of spliced data after splice() returns David Howells
2023-07-19 10:17 ` Miklos Szeredi
2023-07-19 17:59 ` Matt Whitlock [this message]
2023-07-19 19:35 ` Miklos Szeredi
2023-07-19 19:44 ` Matthew Wilcox
2023-07-19 19:56 ` Miklos Szeredi
2023-07-19 20:04 ` Matthew Wilcox
2023-07-19 20:16 ` Linus Torvalds
2023-07-19 21:02 ` Matt Whitlock
2023-07-19 23:20 ` Linus Torvalds
2023-07-19 23:41 ` Matt Whitlock
2023-07-20 0:00 ` Linus Torvalds
2023-07-19 23:48 ` Linus Torvalds
2023-07-24 9:44 ` David Howells
2023-07-24 13:55 ` Miklos Szeredi
2023-07-24 16:15 ` David Howells
2023-06-29 15:54 ` [RFC PATCH 2/4] splice: Make vmsplice() steal or copy David Howells
2023-06-30 13:44 ` Simon Horman
2023-06-30 15:29 ` David Howells
2023-06-30 17:32 ` Simon Horman
2023-06-29 15:54 ` [RFC PATCH 3/4] splice: Remove some now-unused bits David Howells
2023-06-29 15:54 ` [RFC PATCH 4/4] splice: Record some statistics David Howells
2023-06-29 17:56 ` [RFC PATCH 0/4] splice: Fix corruption in data spliced to pipe Linus Torvalds
2023-06-29 18:05 ` Matt Whitlock
2023-06-29 18:19 ` Linus Torvalds
2023-06-29 18:34 ` Matthew Wilcox
2023-06-29 18:53 ` Linus Torvalds
2023-06-30 16:50 ` David Howells
2023-06-29 18:42 ` Linus Torvalds
2023-06-29 18:16 ` Matt Whitlock
2023-06-30 0:01 ` Jakub Kicinski
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