[PATCH AUTOSEL 6.6 042/139] netpoll: Ensure clean state on setup failures
From: Sasha Levin <sashal@kernel.org>
Date: 2024-09-25 12:13:06
Also in:
lkml, stable
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Breno Leitao <leitao@debian.org> [ 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@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> Signed-off-by: Sasha Levin <sashal@kernel.org> --- 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