On Mon, 2006-03-13 at 10:21 -0800, Pete Zaitcev wrote:
> On Mon, 13 Mar 2006 09:51:20 -0600, Paul Fulghum <[EMAIL PROTECTED]> wrote:
>
> > Signed-off-by: Paul Fulghum <[EMAIL PROTECTED]>
>
> > +++ b/drivers/usb/class/cdc-acm.c 2006-03-13 09:33:23.000000000 -0600
> > @@ -517,6 +517,7 @@ static void acm_tty_close(struct tty_str
> > usb_kill_urb(acm->ru[i].urb);
> > } else
> > acm_tty_unregister(acm);
> > + acm->tty = NULL;
>
> Paul, this cannot possibly be correct! The acm_tty_unregister frees
> its argument.
You are right, but only for the path that calls acm_tty_unregister().
For the other path, acm remains with a pointer to a tty which
will be released on return from acm_tty_close().
So how about this:
--- linux-2.6.16-rc5/drivers/usb/class/cdc-acm.c 2006-02-27
14:40:21.000000000 -0600
+++ b/drivers/usb/class/cdc-acm.c 2006-03-13 12:28:19.000000000 -0600
@@ -515,6 +515,7 @@ static void acm_tty_close(struct tty_str
usb_kill_urb(acm->writeurb);
for (i = 0; i < ACM_NRU; i++)
usb_kill_urb(acm->ru[i].urb);
+ acm->tty = NULL;
} else
acm_tty_unregister(acm);
}
> What we actually want is something like this:
>
> --- linux-2.6.16-rc5/drivers/usb/class/cdc-acm.c 2006-02-26
> 23:04:29.000000000 -0800
> +++ linux-2.6.16-rc5-lem/drivers/usb/class/cdc-acm.c 2006-03-13
> 10:20:21.000000000 -0800
> @@ -256,7 +256,7 @@ static void acm_ctrl_irq(struct urb *urb
>
> newctrl = le16_to_cpu(get_unaligned((__le16 *) data));
>
> - if (acm->tty && !acm->clocal && (acm->ctrlin & ~newctrl
> & ACM_CTRL_DCD)) {
> + if (!acm->clocal && (acm->ctrlin & ~newctrl &
> ACM_CTRL_DCD)) {
> dbg("calling hangup");
> tty_hangup(acm->tty);
> }
> @@ -1049,10 +1049,8 @@ static void acm_disconnect(struct usb_in
> return;
> }
>
> + tty_hangup(acm->tty);
> up(&open_sem);
> -
> - if (acm->tty)
> - tty_hangup(acm->tty);
> }
>
> /*
I'm not sure what you are trying to do here.
acm->tty becomes invalid after the last tty close.
You need to NULL that pointer and check for NULL
so you don't touch memory that has been released.
--
Paul Fulghum
Microgate Systems, Ltd
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