From: Breno Leitao <leitao@xxxxxxxxxx> [ Upstream commit ae5a0456e0b4cfd7e61619e55251ffdf1bc7adfb ] 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@xxxxxxxxxx> Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx> Link: https://patch.msgid.link/20240822111051.179850-2-leitao@xxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/core/netpoll.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 55bcacf67df3b..e082139004093 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -626,12 +626,9 @@ 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; } @@ -649,7 +646,7 @@ 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) @@ -660,6 +657,8 @@ 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 */ @@ -677,6 +676,7 @@ 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; @@ -741,6 +741,7 @@ 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) @@ -757,6 +758,7 @@ 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; } @@ -787,6 +789,9 @@ 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(); -- 2.43.0
