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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: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20240822111051.179850-2-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Breno Leitao 2024-08-22 04:10:47 -07:00 committed by Jakub Kicinski
parent f086d18db1
commit ae5a0456e0
1 changed files with 10 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
net/core/netpoll.c
View File

@ -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();