Re: [PATCH] tty: limit TCSBRKP break duration

Xincheng Wang <[email protected]> Wed, 29 Jul 2026 19:19:27 +0800
Newsgroups gmane.linux.kernel,gmane.linux.serial
Message-ID <[email protected]>
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()?

Thanks,
Xincheng