linux-kernel - Re: [Security] Should open TTY device files pin minor numbers?

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Date:	Fri, 24 Jul 2009 22:14:34 -0700
From:	Greg KH <greg@...ah.com>
To:	Alan Stern <stern@...land.harvard.edu>
Cc:	Kernel development list <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	alan@...rguk.ukuu.org.uk
Subject: Re: [Security] Should open TTY device files pin minor numbers?

On Thu, Jul 23, 2009 at 02:38:01PM -0400, Alan Stern wrote:
> Recent work in the TTY core and in usb-serial has caused a change 
> in behavior between 2.6.30 and 2.6.31-rc.  Namely, if a USB serial 
> device is unplugged while a process holds the device file open, the 
> minor number won't get reused until the process closes the file.

That's how the usb-serial code always worked, this is nothing new at
all.

> For example, if you run minicom over /dev/ttyUSB0, unplug the USB
> device while minicom is running, and then plug it in again before
> exiting minicom, it will reappear as /dev/ttyUSB1 instead of
> /dev/ttyUSB0 (which will be gone).

Exactly.  People are used to this by now, it shouldn't be a supprise :)

thanks,

greg k-h
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