Re: [PATCH 1/3] usb,console: Fix regression in usb console onkernel boot

From: Alan Cox
Date: Thu Jun 18 2009 - 05:10:26 EST

On Wed, 17 Jun 2009 21:20:07 -0500
Jason Wessel <jason.wessel@xxxxxxxxxxxxx> wrote:

> The commit 335f8514f200e63d689113d29cb7253a5c282967 introduced a
> regression which stopped usb consoles from working correctly as a
> kernel boot console as well as interactive login device.
> The addition of the serial_close() which in turn calls
> tty_port_close_start() will change the reference count of port.count
> and warn about it. The usb console code had previously incremented
> the port.count to indicate it was making use of the device as a
> console and the forced change causes a double open on the usb device
> which leads to a non obvious kernel oops later on when the tty is
> freed.
> To fix the problem instead make use of port->console to track if the
> port is in fact an active console port to avoid double initialization
> of the usb serial device. The port.count is incremented and
> decremented only with in the scope of usb_console_setup() for the
> purpose of the low level driver initialization.

Acked-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
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