Commit ae5a0456 authored by Breno Leitao's avatar Breno Leitao Committed by Jakub Kicinski
Browse files

netpoll: Ensure clean state on setup failures 



Modify netpoll_setup() and __netpoll_setup() to ensure that the netpoll
structure (np) is left in a clean state if setup fails for any reason.
This prevents carrying over misconfigured fields in case of partial
setup success.

Key changes:
- np->dev is now set only after successful setup, ensuring it's always
  NULL if netpoll is not configured or if netpoll_setup() fails.
- np->local_ip is zeroed if netpoll setup doesn't complete successfully.
- Added DEBUG_NET_WARN_ON_ONCE() checks to catch unexpected states.
- Reordered some operations in __netpoll_setup() for better logical flow.

These changes improve the reliability of netpoll configuration, since it
assures that the structure is fully initialized or totally unset.

Suggested-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarBreno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20240822111051.179850-2-leitao@debian.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent f086d18d

net/core/netpoll.c

+10 −5
Original line number Diff line number Diff line
@@ -624,12 +624,9 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) 
	const struct net_device_ops *ops;

	int err;



	np->dev = ndev;

	strscpy(np->dev_name, ndev->name, IFNAMSIZ);



	if (ndev->priv_flags & IFF_DISABLE_NETPOLL) {

		np_err(np, "%s doesn't support polling, aborting\n",

		       np->dev_name);

		       ndev->name);

		err = -ENOTSUPP;

		goto out;

	}
@@ -647,7 +644,7 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) 


		refcount_set(&npinfo->refcnt, 1);



		ops = np->dev->netdev_ops;

		ops = ndev->netdev_ops;

		if (ops->ndo_netpoll_setup) {

			err = ops->ndo_netpoll_setup(ndev, npinfo);

			if (err)
@@ -658,6 +655,8 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) 
		refcount_inc(&npinfo->refcnt);

	}



	np->dev = ndev;

	strscpy(np->dev_name, ndev->name, IFNAMSIZ);

	npinfo->netpoll = np;



	/* last thing to do is link it to the net device structure */
@@ -675,6 +674,7 @@ EXPORT_SYMBOL_GPL(__netpoll_setup); 
int netpoll_setup(struct netpoll *np)

{

	struct net_device *ndev = NULL;

	bool ip_overwritten = false;

	struct in_device *in_dev;

	int err;
@@ -739,6 +739,7 @@ int netpoll_setup(struct netpoll *np) 
			}



			np->local_ip.ip = ifa->ifa_local;

			ip_overwritten = true;

			np_info(np, "local IP %pI4\n", &np->local_ip.ip);

		} else {

#if IS_ENABLED(CONFIG_IPV6)
@@ -755,6 +756,7 @@ int netpoll_setup(struct netpoll *np) 
					    !!(ipv6_addr_type(&np->remote_ip.in6) & IPV6_ADDR_LINKLOCAL))

						continue;

					np->local_ip.in6 = ifp->addr;

					ip_overwritten = true;

					err = 0;

					break;

				}
@@ -785,6 +787,9 @@ int netpoll_setup(struct netpoll *np) 
	return 0;



put:

	DEBUG_NET_WARN_ON_ONCE(np->dev);

	if (ip_overwritten)

		memset(&np->local_ip, 0, sizeof(np->local_ip));

	netdev_put(ndev, &np->dev_tracker);

unlock:

	rtnl_unlock();