Re: 2.5.x opps stopping serial

Paul Larson
2002-10-15T20:35:21Z

On Fri, 2002-10-11 at 07:45, Ed Tomlinson wrote:
> Hi,
>
> I have been seeing this during shutdown ever since I started using 2.5. Figured
> I really should report it... There are three serial ports. One for a serial console,
> the second for a backUPS ups, the third for a (real) modem. Dist is debian sid.
>
> Saving state of known serial devices... Unable to handle kernel NULL pointer dereference at virtual addres
Looks like it might be similar to one I saw with smatch recently. There
are several places in core.c that check info->tty before dereferencing
it, but others that don't. I don't think this will fix the one you are
seeing, but if it's easily reproducible you could try doing something
similar in uart_block_til_ready.

--- linux-2.5/drivers/serial/core.c Wed Oct 9 13:45:11 2002
+++ linux-corefix/drivers/serial/core.c Wed Oct 9 13:50:09 2002
@@ -207,7 +207,7 @@
* Setup the RTS and DTR signals once the
* port is open and ready to respond.
*/
- if (info->tty->termios->c_cflag & CBAUD)
+ if (info->tty && (info->tty->termios->c_cflag & CBAUD))
uart_set_mctrl(port, TIOCM_RTS | TIOCM_DTR);
}

Thanks,
Paul Larson