From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 22C1E2FAC11; Tue, 12 Aug 2025 18:37:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755023871; cv=none; b=U/v2f+oCPn7ddemXEUdvrwwdSdxqu1vcodQB4yY5XF9bAxmzpBVmCEfZ1S9YRKSZVHS+goYZFCszsFENjKkr3yD6YXwW6PUcgvgwBtiYdK5kwsIH86QL+8yXxShzVrNeyJdxRPjhJrWV3S0XzWd6PqosVNPrE6bHqt7p/fXkJ58= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755023871; c=relaxed/simple; bh=7MS+Bxux3bhxPcr/McyJl9rA9Z3dOjMZVNI7hk8eo3Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eeVZKxVnHXTMbrHF+fE+CUzDNdSYuuKBEO74/jUUyQdBaDscsG48z5XIFNQe/S66hxfLWLueLSZYMRsLes/JLHlLCGrAgs7HF1P2RIOIxGECNsI2No11fsJqXk8Btw3tVr0zxtiNd0FbzrmWWDM5RUoTz25Lb3JkeSy2Fdunxxw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TcvX+6tm; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="TcvX+6tm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 86044C4CEF0; Tue, 12 Aug 2025 18:37:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755023871; bh=7MS+Bxux3bhxPcr/McyJl9rA9Z3dOjMZVNI7hk8eo3Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TcvX+6tmVffHm5WgypAbQ73yHvdmnygnkX4Ft8GJC6SAChW5d4IVdzkTjDuHes76H hO6gmAw6D4aIuJnd3Bd+io4fbk71VVHcHXhyrQwHO7qyeh9yOxuJzfOU4BFoMDolfc p+WP4RIAPL0Bjgbv/DebnrXDmCe4ZhaNgjd6+O5E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Kuniyuki Iwashima , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.16 174/627] net: dst: annotate data-races around dst->input Date: Tue, 12 Aug 2025 19:27:49 +0200 Message-ID: <20250812173425.898637634@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250812173419.303046420@linuxfoundation.org> References: <20250812173419.303046420@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit f1c5fd34891a1c242885f48c2e4dc52df180f311 ] dst_dev_put() can overwrite dst->input while other cpus might read this field (for instance from dst_input()) Add READ_ONCE()/WRITE_ONCE() annotations to suppress potential issues. We will likely need full RCU protection later. Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()") Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250630121934.3399505-5-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- include/net/dst.h | 2 +- include/net/lwtunnel.h | 4 ++-- net/core/dst.c | 2 +- net/ipv4/route.c | 2 +- 4 files changed, 5 insertions(+), 5 deletions(-) diff --git a/include/net/dst.h b/include/net/dst.h index 78c78cdce0e9..65d81116d6bf 100644 --- a/include/net/dst.h +++ b/include/net/dst.h @@ -466,7 +466,7 @@ INDIRECT_CALLABLE_DECLARE(int ip_local_deliver(struct sk_buff *)); /* Input packet from network to transport. */ static inline int dst_input(struct sk_buff *skb) { - return INDIRECT_CALL_INET(skb_dst(skb)->input, + return INDIRECT_CALL_INET(READ_ONCE(skb_dst(skb)->input), ip6_input, ip_local_deliver, skb); } diff --git a/include/net/lwtunnel.h b/include/net/lwtunnel.h index c306ebe379a0..eaac07d50595 100644 --- a/include/net/lwtunnel.h +++ b/include/net/lwtunnel.h @@ -142,8 +142,8 @@ static inline void lwtunnel_set_redirect(struct dst_entry *dst) dst->output = lwtunnel_output; } if (lwtunnel_input_redirect(dst->lwtstate)) { - dst->lwtstate->orig_input = dst->input; - dst->input = lwtunnel_input; + dst->lwtstate->orig_input = READ_ONCE(dst->input); + WRITE_ONCE(dst->input, lwtunnel_input); } } #else diff --git a/net/core/dst.c b/net/core/dst.c index 795ca07e28a4..b46f7722a1b6 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -148,7 +148,7 @@ void dst_dev_put(struct dst_entry *dst) dst->obsolete = DST_OBSOLETE_DEAD; if (dst->ops->ifdown) dst->ops->ifdown(dst, dev); - dst->input = dst_discard; + WRITE_ONCE(dst->input, dst_discard); dst->output = dst_discard_out; dst->dev = blackhole_netdev; netdev_ref_replace(dev, blackhole_netdev, &dst->dev_tracker, diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 64ac20c27f1b..2cc88f8c3bc6 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1685,7 +1685,7 @@ struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt) else if (rt->rt_gw_family == AF_INET6) new_rt->rt_gw6 = rt->rt_gw6; - new_rt->dst.input = rt->dst.input; + new_rt->dst.input = READ_ONCE(rt->dst.input); new_rt->dst.output = rt->dst.output; new_rt->dst.error = rt->dst.error; new_rt->dst.lastuse = jiffies; -- 2.39.5