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tty: Prevent tty_port destruction if tty not released 

If the tty driver mistakenly drops the last port reference
before the tty has been released, issue a diagnostic and
abort the port destruction.

This will leak memory and may zombify the port, but might
otherwise keep the machine in runnable state.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley 2013-09-18 20:42:39 -04:00 committed by Greg Kroah-Hartman
parent 103fcbe2ee
commit e3bfea23a6
1 changed files with 4 additions and 0 deletions
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4
drivers/tty/tty_port.c
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@ -140,6 +140,10 @@ EXPORT_SYMBOL(tty_port_destroy);
static void tty_port_destructor(struct kref *kref)
{
struct tty_port *port = container_of(kref, struct tty_port, kref);
/* check if last port ref was dropped before tty release */
if (WARN_ON(port->itty))
return;
if (port->xmit_buf)
free_page((unsigned long)port->xmit_buf);
tty_port_destroy(port);