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From: Al Viro <viro@zeniv.linux.org.uk>
To: Gary Guo <gary@garyguo.net>
Cc: "Christian Brauner" <brauner@kernel.org>,
	"Alice Ryhl" <aliceryhl@google.com>,
	"Georgios Androutsopoulos" <georgeandrout13@gmail.com>,
	"Miguel Ojeda" <ojeda@kernel.org>, "Jan Kara" <jack@suse.cz>,
	"Boqun Feng" <boqun@kernel.org>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Benno Lossin" <lossin@kernel.org>,
	"Andreas Hindborg" <a.hindborg@kernel.org>,
	"Trevor Gross" <tmgross@umich.edu>,
	"Danilo Krummrich" <dakr@kernel.org>,
	"Daniel Almeida" <daniel.almeida@collabora.com>,
	"Tamir Duberstein" <tamird@kernel.org>,
	"Alexandre Courbot" <acourbot@nvidia.com>,
	"Onur Özkan" <work@onurozkan.dev>,
	linux-fsdevel@vger.kernel.org, rust-for-linux@vger.kernel.org,
	linux-kernel@vger.kernel.org, "Al Viro" <viro@ftp.linux.org.uk>
Subject: Re: [PATCH v2] rust: file: handle fd table teardown in file descriptor APIs
Date: Tue, 29 Sep 2026 18:02:18 +0100	[thread overview]
Message-ID: <20260929170218.GD989762@ZenIV> (raw)
In-Reply-To: <DLRXHGLDR2QQ.WZVRWGY995BT@garyguo.net>

On Tue, Sep 29, 2026 at 05:07:40PM +0100, Gary Guo wrote:

> The reproducer that Georgios posted on GitHub is some cleanup job being added to
> task_work, which drops FileDescriptorReservation. And since exit_task_work()
> happens after exit_files(), put_unused_fd in that cleanup observe that
> current->files is NULL.
>
> So it's not from random thread, it's from the current task. And I find that
> particular case of doing per-task cleanup not unrealistic.

FWIW, descriptor reservation ought to be tied to specific files_struct
instance; note that dup_fd() can be called when there are outstanding
reservations and the copy does *NOT* have those reserved.

What rules would you suggest for such delayed put_unused_fd() wrt e.g.
files_struct unsharing?

  reply	other threads:[~2026-09-29 17:02 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-23  2:23 Georgios Androutsopoulos
2026-09-24  8:39 ` Alice Ryhl
2026-09-24 16:06   ` Georgios Androutsopoulos
2026-09-24 16:18     ` Pedro Falcato
2026-09-25 16:00   ` Christian Brauner
2026-09-29  4:48     ` Al Viro
2026-09-29  8:49       ` Alice Ryhl
2026-09-29 13:28         ` Al Viro
2026-09-29 13:35           ` Alice Ryhl
2026-09-29 14:53             ` Al Viro
2026-09-29 12:24       ` Gary Guo
2026-09-29 13:51         ` Al Viro
2026-09-29 16:07           ` Gary Guo
2026-09-29 17:02             ` Al Viro [this message]
2026-09-29 18:22               ` Gary Guo
2026-09-28 10:42 ` kernel test robot

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