On Mon, Dec 01, 2025 at 02:48:48PM -0800, Chris Mason wrote: > On Mon, 1 Dec 2025 20:52:34 +0100 Jonas Gorski <[email protected]> wrote: > > > Hi, > > > > On Mon, Dec 1, 2025 at 3:48 PM Simon Horman <[email protected]> wrote: > > > > > > On Mon, Dec 01, 2025 at 11:28:13AM +0100, Jonas Gorski wrote: > > > > > > ... > > > > > > > diff --git a/net/dsa/user.c b/net/dsa/user.c > > > > index f59d66f0975d..fa1fe0f1493a 100644 > > > > --- a/net/dsa/user.c > > > > +++ b/net/dsa/user.c > > > > @@ -653,21 +653,30 @@ static int dsa_user_port_attr_set(struct > > > > net_device *dev, const void *ctx, > > > > > > > > /* Must be called under rcu_read_lock() */ > > > > static int > > > > -dsa_user_vlan_check_for_8021q_uppers(struct net_device *user, > > > > +dsa_user_vlan_check_for_8021q_uppers(struct dsa_port *dp, > > > > const struct switchdev_obj_port_vlan > > > > *vlan) > > > > { > > > > - struct net_device *upper_dev; > > > > - struct list_head *iter; > > > > + struct dsa_switch *ds = dp->ds; > > > > + struct dsa_port *other_dp; > > > > > > > > - netdev_for_each_upper_dev_rcu(user, upper_dev, iter) { > > > > - u16 vid; > > > > + dsa_switch_for_each_user_port(other_dp, ds) { > > > > + struct net_device *user = other_dp->user; > > > > > > Hi Jonas, > > > > > > The AI robot is concerned that user may be NULL here. > > > And I can't convince myself that cannot be the case. > > > > > > Could you take a look? > > > > > > https://netdev-ai.bots.linux.dev/ai-review.html?id=47057e-e740-4b66-9d60-9ec2a7ee92a1#patch-0 > > > > At this point it can be NULL. But it being NULL is not an issue, as ... > > > > > > > + struct net_device *upper_dev; > > > > + struct list_head *iter; > > > > > > > > - if (!is_vlan_dev(upper_dev)) > > > > + if (!dsa_port_bridge_same(dp, other_dp)) > > > > continue; > > > > ... this condition will filter all cases where it is NULL. For > > dsa_port_bridge_same() to return true both ports need to be attached > > to a bridge (and to the same bridge), and to be attached to a bridge a > > net_device is required, so other_dp->user cannot be NULL. And we only > > access user after here.
Thanks for the explanation Jonas. I wasn't very confident with this report. And I was too focused on working out if user could be NULL rather than if it matters. Still, I may not have worked it out. > > I reproduced this false positive here, thanks for the explanation. This is an > example of a class of review mistakes I've wanted to fix, so I used it to > improve the prompts around NULL pointers that are protected via other checks. > > I'll test this on some more commits and push it out. Thanks for following-up on this Chris. I guess everyone has their own opinion on AI. And, in a similar vein, many have opinions on the review-prompts. But, FTR, I've been impressed by the output I've seen, having used them for a few weeks now. And I look forward to that improving further.
