All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Ahelenia Ziemiańska" <nabijaczleweli@nabijaczleweli.xyz>
Cc: Jens Axboe <axboe@kernel.dk>,
	Christian Brauner <brauner@kernel.org>,
	 Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel@vger.kernel.org,
	 Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	linux-kernel@vger.kernel.org,  linux-serial@vger.kernel.org
Subject: [PATCH v2 08/11] tty: splice_read: disable
Date: Thu, 21 Dec 2023 04:09:10 +0100	[thread overview]
Message-ID: <4dec932dcd027aa5836d70a6d6bedd55914c84c2.1703126594.git.nabijaczleweli@nabijaczleweli.xyz> (raw)
In-Reply-To: <cover.1703126594.git.nabijaczleweli@nabijaczleweli.xyz>

[-- Attachment #1: Type: text/plain, Size: 1463 bytes --]

We request non-blocking I/O in the generic copy_splice_read, but
"the tty layer doesn't actually honor the IOCB_NOWAIT flag for
various historical reasons.". This means that a tty->pipe splice
will happily sleep with the pipe locked forever, and any process
trying to take it (due to an open/read/write/&c.) will enter
uninterruptible sleep.

This also masks inconsistent wake-ups (usually every second line)
when splicing from ttys in icanon mode.

Link: https://lore.kernel.org/linux-fsdevel/CAHk-=wimmqG_wvSRtMiKPeGGDL816n65u=Mq2+H3-=uM2U6FmA@mail.gmail.com/
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
---
 drivers/tty/tty_io.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 06414e43e0b5..50c2957a9c7f 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -465,7 +465,6 @@ static const struct file_operations tty_fops = {
 	.llseek		= no_llseek,
 	.read_iter	= tty_read,
 	.write_iter	= tty_write,
-	.splice_read	= copy_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.poll		= tty_poll,
 	.unlocked_ioctl	= tty_ioctl,
@@ -480,7 +479,6 @@ static const struct file_operations console_fops = {
 	.llseek		= no_llseek,
 	.read_iter	= tty_read,
 	.write_iter	= redirected_tty_write,
-	.splice_read	= copy_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.poll		= tty_poll,
 	.unlocked_ioctl	= tty_ioctl,
-- 
2.39.2

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

  parent reply	other threads:[~2023-12-21  3:09 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-21  3:08 [PATCH v2 00/11] Avoid unprivileged splice(file->)/(->socket) pipe exclusion Ahelenia Ziemiańska
2023-12-21  3:08 ` [PATCH v2 01/11] splice: copy_splice_read: do the I/O with IOCB_NOWAIT Ahelenia Ziemiańska
2023-12-21  8:27   ` Christoph Hellwig
2023-12-21 16:30     ` Ahelenia Ziemiańska
2023-12-21  3:08 ` [PATCH v2 02/11] af_unix: unix_stream_splice_read: always request MSG_DONTWAIT Ahelenia Ziemiańska
2023-12-21  3:08 ` [PATCH v2 03/11] fuse: fuse_dev_splice_read: use nonblocking I/O Ahelenia Ziemiańska
2023-12-21  3:09 ` [PATCH v2 04/11] net/smc: smc_splice_read: always request MSG_DONTWAIT Ahelenia Ziemiańska
2023-12-21  3:09 ` [PATCH v2 05/11] kcm: kcm_splice_read: " Ahelenia Ziemiańska
2023-12-21  3:09 ` [PATCH v2 06/11] tls/sw: tls_sw_splice_read: always request non-blocking I/O Ahelenia Ziemiańska
2023-12-21  3:09 ` [PATCH v2 07/11] net/tcp: tcp_splice_read: always do non-blocking reads Ahelenia Ziemiańska
2023-12-21  3:09 ` Ahelenia Ziemiańska [this message]
2023-12-21  8:10   ` [PATCH v2 08/11] tty: splice_read: disable Greg Kroah-Hartman
2024-01-03 11:36   ` Jiri Slaby
2024-01-03 19:14     ` Linus Torvalds
2024-01-03 21:34       ` Oliver Giles
2024-01-03 21:57         ` Linus Torvalds
2023-12-21  3:09 ` [PATCH v2 09/11] fuse: file: limit splice_read to virtiofs Ahelenia Ziemiańska
2024-01-10 13:43   ` Miklos Szeredi
2024-01-10 15:19     ` Ahelenia Ziemiańska
2024-01-10 15:47       ` Miklos Szeredi
2023-12-21  3:09 ` [PATCH v2 10/11] fuse: allow splicing from filesystems mounted by real root Ahelenia Ziemiańska
2023-12-21  3:09 ` [PATCH v2 11/11] splice: splice_to_socket: always request MSG_DONTWAIT Ahelenia Ziemiańska
2023-12-21  3:09 ` [PATCH v2 12/11 man-pages] splice.2: document 6.8 blocking behaviour Ahelenia Ziemiańska
2023-12-24  5:01 ` [PATCH v2 13/11] tty: splice_write: disable Ahelenia Ziemiańska
2023-12-24  5:01 ` [PATCH v2 14/11] fuse: allow splicing to trusted mounts only Ahelenia Ziemiańska

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=4dec932dcd027aa5836d70a6d6bedd55914c84c2.1703126594.git.nabijaczleweli@nabijaczleweli.xyz \
    --to=nabijaczleweli@nabijaczleweli.xyz \
    --cc=axboe@kernel.dk \
    --cc=brauner@kernel.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=jirislaby@kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-serial@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.