From: Ido Schimmel <idosch@nvidia.com>
To: Linmao Li <lilinmao@kylinos.cn>
Cc: davem@davemloft.net, dsahern@kernel.org, edumazet@google.com,
kuba@kernel.org, pabeni@redhat.com, horms@kernel.org,
stephen@networkplumber.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net v4] ipv6: addrconf: skip ERRDAD transition when address already DEAD
Date: Wed, 29 Apr 2026 12:08:22 +0300 [thread overview]
Message-ID: <20260429090822.GA758041@shredder> (raw)
In-Reply-To: <20260429012651.1580303-1-lilinmao@kylinos.cn>
On Wed, Apr 29, 2026 at 09:26:51AM +0800, Linmao Li wrote:
> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> index 5476b6536eb7..b58bd9f11606 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -2166,16 +2166,18 @@ void addrconf_dad_failure(struct sk_buff *skb, struct inet6_ifaddr *ifp)
> struct net *net = dev_net(idev->dev);
> int max_addresses;
>
> - if (addrconf_dad_end(ifp)) {
> + spin_lock_bh(&ifp->lock);
> +
> + if (ifp->state != INET6_IFADDR_STATE_DAD) {
> + spin_unlock_bh(&ifp->lock);
> in6_ifa_put(ifp);
> return;
> }
> + ifp->state = INET6_IFADDR_STATE_POSTDAD;
>
> net_info_ratelimited("%s: IPv6 duplicate address %pI6c used by %pM detected!\n",
> ifp->idev->dev->name, &ifp->addr, eth_hdr(skb)->h_source);
>
> - spin_lock_bh(&ifp->lock);
> -
> if (ifp->flags & IFA_F_STABLE_PRIVACY) {
> struct in6_addr new_addr;
> struct inet6_ifaddr *ifp2;
> @@ -2223,6 +2225,11 @@ void addrconf_dad_failure(struct sk_buff *skb, struct inet6_ifaddr *ifp)
> in6_ifa_put(ifp2);
> lock_errdad:
> spin_lock_bh(&ifp->lock);
> + if (ifp->state == INET6_IFADDR_STATE_DEAD) {
The code below expects the state to be POSTDAD, so wouldn't it be more
robust to check for anything but POSTDAD rather than specifically
checking for DEAD? Otherwise we risk overwriting a state that was set
while we weren't holding the lock.
Also:
1. Please post new versions in a new thread:
https://docs.kernel.org/process/maintainer-netdev.html#resending-after-review
2. Please include a change log:
https://docs.kernel.org/process/maintainer-netdev.html#changes-requested
> + spin_unlock_bh(&ifp->lock);
> + in6_ifa_put(ifp);
> + return;
> + }
> }
>
> errdad:
> --
> 2.25.1
>
prev parent reply other threads:[~2026-04-29 9:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-20 3:28 [PATCH net] ipv6: addrconf: skip ERRDAD transition when address already DEAD Linmao Li
2026-04-21 7:50 ` [PATCH net v2] " Linmao Li
2026-04-22 10:43 ` Sabrina Dubroca
2026-04-23 2:32 ` [PATCH net v3] " Linmao Li
2026-04-28 10:59 ` Paolo Abeni
2026-04-29 1:26 ` [PATCH net v4] " Linmao Li
2026-04-29 9:08 ` Ido Schimmel [this message]
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