Re: Linux 2.6.28-rc2 i/o error on /dev/ttyUSB0

[Alan Cox <alan@lxorguk.ukuu.org.uk>]

On Wed, 29 Oct 2008 13:28:42 +0100
Helge Hafting <helge.hafting@aitel.hist.no> wrote:

> Alan Cox wrote:
> >> squarely in the "oops, kref's are screwed up" corner, and you should talk 
> >> to Alan about your particular USB dongle. I bet that bisection would just 
> >> show you one of the kref commits (eg 4a90f09b "tty: usb-serial krefs" or 
> >> maybe 7d7b93c14 "tty: kref the tty driver object"). 

Please try:

tty: Fix USB kref leak

From: Alan Cox <alan@redhat.com>

When we close we must clear the extra reference we got when we read
port->tty. Setting the port tty NULL will clear the kref held by the driver
but not the one we obtained ourselves while doing the lookup.

Signed-off-by: Alan Cox <alan@redhat.com>
---

 drivers/usb/serial/usb-serial.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)


diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 8be3f39..794b5ff 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -281,6 +281,7 @@ static void serial_close(struct tty_struct *tty, struct file *filp)
 			if (tty->driver_data)
 				tty->driver_data = NULL;
 			tty_port_tty_set(&port->port, NULL);
+			tty_kref_put(tty);
 		}
 	}