From: Matthew Wilcox <willy@infradead.org>
To: David Howells <dhowells@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>,
Matt Whitlock <kernel@mattwhitlock.name>,
linux-fsdevel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Jens Axboe <axboe@kernel.dk>, Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [Reproducer] Corruption, possible race between splice and FALLOC_FL_PUNCH_HOLE
Date: Wed, 28 Jun 2023 13:51:45 +0100 [thread overview]
Message-ID: <ZJws4Yr9tcaF7Mis@casper.infradead.org> (raw)
In-Reply-To: <3388728.1687944804@warthog.procyon.org.uk>
On Wed, Jun 28, 2023 at 10:33:24AM +0100, David Howells wrote:
> Would you consider it a kernel bug, then, if you use sendmsg(MSG_ZEROCOPY) to
> send some data from a file mmapping that some other userspace then corrupts by
> altering the file before the kernel has managed to send it?
I think there's a difference in that sendmsg() will block until it
returns (... right?) splice() returns. That implies the copy is done.
Then the same thread modifies the file, but the pipe sees the new
data, not the old. Doesn't that feel like a bug to you?
next prev parent reply other threads:[~2023-06-28 12:54 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-27 1:12 [Reproducer] Corruption, possible race between splice and FALLOC_FL_PUNCH_HOLE Matt Whitlock
2023-06-27 5:47 ` Dave Chinner
2023-06-27 6:20 ` Dave Chinner
2023-06-27 10:31 ` Matthew Wilcox
2023-06-27 18:38 ` Matt Whitlock
2023-06-27 21:49 ` Dave Chinner
2023-06-27 18:14 ` Matt Whitlock
2023-06-27 21:51 ` Dave Chinner
2023-06-28 6:30 ` David Howells
2023-06-28 8:15 ` Dave Chinner
2023-06-28 9:33 ` David Howells
2023-06-28 12:51 ` Matthew Wilcox [this message]
2023-06-28 14:19 ` David Howells
2023-06-28 22:41 ` Dave Chinner
2023-06-28 17:35 ` Matt Whitlock
2023-06-28 18:27 ` David Howells
2023-06-28 22:17 ` Dave Chinner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ZJws4Yr9tcaF7Mis@casper.infradead.org \
--to=willy@infradead.org \
--cc=axboe@kernel.dk \
--cc=david@fromorbit.com \
--cc=dhowells@redhat.com \
--cc=hch@lst.de \
--cc=kernel@mattwhitlock.name \
--cc=linux-fsdevel@vger.kernel.org \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).