From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Xincheng Wang <22009200607@stu.xidian.edu.cn>
Cc: Jiri Slaby <jirislaby@kernel.org>,
linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org
Subject: Re: [PATCH] tty: limit TCSBRKP break duration
Date: Mon, 27 Jul 2026 08:25:02 +0200 [thread overview]
Message-ID: <2026072700-causal-remarry-6edf@gregkh> (raw)
In-Reply-To: <20260727055525.6170-1-22009200607@stu.xidian.edu.cn>
On Mon, Jul 27, 2026 at 01:55:25PM +0800, Xincheng Wang wrote:
> An RCU stall was observed while exercising tty ioctls on an
> 8250 Pericom PCI serial port.
>
> The reproducer passed a very large argument to TCSBRKP. tty_ioctl()
> multiplies the argument by 100 and forwards it to send_break(), whose
> duration is an unsigned int. That can leave the serial break condition
> asserted for an extremely long time and keep the IRQ line active on the
> affected setup.
>
> Clamp the duration before calling send_break() so normal values keep
> their current behavior, while preventing excessively long break
> intervals.
How do we know that systems don't want those long break intervals set?
You are changing something that might break people's working systems.
What specific error are you getting when you send a long break time and
why can't your hardware handle that?
thanks,
greg k-h
prev parent reply other threads:[~2026-07-27 6:25 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-27 5:55 [PATCH] tty: limit TCSBRKP break duration Xincheng Wang
2026-07-27 6:25 ` Greg Kroah-Hartman [this message]
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=2026072700-causal-remarry-6edf@gregkh \
--to=gregkh@linuxfoundation.org \
--cc=22009200607@stu.xidian.edu.cn \
--cc=jirislaby@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
/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