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: Wed, 29 Jul 2026 13:50:43 +0200 [thread overview]
Message-ID: <2026072921-curled-moonlike-1207@gregkh> (raw)
In-Reply-To: <20260729111927.41154-1-22009200607@stu.xidian.edu.cn>
On Wed, Jul 29, 2026 at 07:19:27PM +0800, Xincheng Wang wrote:
> Hi Greg,
>
> Thanks for the review.
>
> You are right. The RCU stall I observed does not by itself justify
> clamping long break intervals in the tty core, so I will drop that
> patch.
>
> While looking at this path, I noticed that tty_ioctl() multiplies the
> TCSBRKP argument by 100 and passes the result to send_break(), whose
> duration argument is unsigned int. Values whose product exceeds UINT_MAX
> are silently truncated to an unintended duration.
>
> Do you think it is worth fixing that separately by rejecting TCSBRKP
> values that cannot fit in the unsigned-int millisecond duration used by
> send_break()?
Wouldn't that break userspace that is currently relying on that
truncation?
thanks,
greg k-h
next prev parent reply other threads:[~2026-07-29 11:50 UTC|newest]
Thread overview: 6+ 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
2026-07-29 11:19 ` Xincheng Wang
2026-07-29 11:50 ` Greg Kroah-Hartman [this message]
2026-07-31 14:30 ` Xincheng Wang
2026-07-31 15:04 ` Greg Kroah-Hartman
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