Re: IPv6 oops on ifup in latest BK

["David S. Miller" <davem@xxxxxxxxxx>]

On Tue, 24 Aug 2004 02:07:28 -0400
Jeff Garzik <jgarzik@xxxxxxxxx> wrote:

> Attached minicom.cap.txt gives the ksymoops output and dmesg output. 
> Appears to die in ipv6_get_hoplimit.

Yoshifuji-san, it is rt6i_dev changes.  The problem is that
ipv6_get_hoplimit() gets called with NULL dev.

I believe it is an error in the logic for RTCF_REJECT
processing.  If user does not specify a specific device
index, and this is RTCF_REJECT, then we will end up
with dev being NULL.

It is this piece of code in ip6_route_add():

                if (dev && dev != &loopback_dev) {

It does not handle the case where dev == NULL correctly.
Original code did do the right thing:

                if (dev)
                        dev_put(dev);
                dev = &loopback_dev;
                dev_hold(dev);

Maybe new code should be something like:

                if (dev && dev != &loopback_dev) {
                        dev_put(dev);
                        in6_dev_put(idev);
                }
                dev = &loopback_dev;
                dev_hold(dev);
                idev = in6_dev_get(dev);
                if (!idev) {
                        err = -ENODEV;
                        goto out;
                }

What do you think?