Subject: Re: [PATCH net-next,v3] bonding: use WARN_ON instead of BUG in alb_upper_dev_walk

From: Simon Horman <[email-masked]>
Date: Wed, 15 Nov 2023 17:49:55 +0000

On Wed, Nov 15, 2023 at 03:22:39PM +0100, Jiri Pirko wrote:
> Wed, Nov 15, 2023 at 12:55:37PM CET, [email-masked] wrote:
> >If failed to allocate "tags" or could not find the final upper device from
> >start_dev's upper list in bond_verify_device_path(), only the loopback
> >detection of the current upper device should be affected, and the system is
> >no need to be panic.
> >
> >Signed-off-by: Zhengchao Shao <[email-masked]>
> >---
> >v3: return -ENOMEM instead of zero to stop walk
> >v2: use WARN_ON_ONCE instead of WARN_ON
> 
> Yet the WARN_ON is back :O

Hi Jiri,

I think the suggestion was to either:

1. WARN_ON_ONCE(); return 0;      <= this was v2
2. WARN_ON(); return -ESOMETHING; <= this is v3
(But not, WARN_ON(); return 0;    <= this was v1)

And after v2 it was determined that the approach taken here in v3 is
preferred.

So I think this patch is consistent with the feedback given by Jay
in his reviews so far.

> 
> 
> >---
> > drivers/net/bonding/bond_alb.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> >diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
> >index dc2c7b979656..21f1cb8e453b 100644
> >--- a/drivers/net/bonding/bond_alb.c
> >+++ b/drivers/net/bonding/bond_alb.c
> >@@ -984,8 +984,10 @@ static int alb_upper_dev_walk(struct net_device *upper,
> > 	 */
> > 	if (netif_is_macvlan(upper) && !strict_match) {
> > 		tags = bond_verify_device_path(bond->dev, upper, 0);
> >-		if (IS_ERR_OR_NULL(tags))
> >-			BUG();
> >+		if (IS_ERR_OR_NULL(tags)) {
> >+			WARN_ON(1);
> >+			return -ENOMEM;
> >+		}
> > 		alb_send_lp_vid(slave, upper->dev_addr,
> > 				tags[0].vlan_proto, tags[0].vlan_id);
> > 		kfree(tags);
> >-- 
> >2.34.1
> >
> >
>