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 D7EF02FA0DB; Tue, 12 Aug 2025 17:56:22 +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=1755021382; cv=none; b=SrqR/JAy5V62+EXPJZk+vdYcA5J1RJca1dKLm/ooZKUw3/wZ5JssL8HKdImAmaW8q7He0TOYLlF0T2AzpSWyATwzXVBbIua6egNU51aL8f4WuSDZbr+bKLEqQOG8X5XXOlH/osPWkEoQXM0y2Y2UEpxCp8oTeKe9LDCqm8O5v2U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755021382; c=relaxed/simple; bh=hAoaE51QVvkP1dwlt+TZqi0sYCNixNX+G4xol3MbWAk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oELIGwJt50K4O4NwnBP/98DclSZtSeJGwnEtFt8DsdMHOllojPq1fOCj4p207VTpVNIM6gulcnzS185Q9hOG33b0r28MZlc4X0PJJ1fH9wfvk0SJVdB0Zw/y0S0xL01cRBxJ4FcLqGR2Z23DWcSouA9Y0g8Mk5PPgzsZEoreZc4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mx31Cy84; 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="mx31Cy84" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 46D04C4CEF0; Tue, 12 Aug 2025 17:56:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755021382; bh=hAoaE51QVvkP1dwlt+TZqi0sYCNixNX+G4xol3MbWAk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mx31Cy84bd9cW16YDbbw5rioFhNXbkay40xgvJAgWtBvJmOcnzm95/M3AmW6onECe JSy45a/+QBiGoxNVcuu/N8EiEbPHFeE5sMvtiI9o3uaX4KGpu9R4TfLrR+jjzqNDGz +ecOUOQNlIeNeazZyRYuE15CT3r3Nkvjoi8A2KHs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 105/262] ipv6: annotate data-races around rt->fib6_nsiblings Date: Tue, 12 Aug 2025 19:28:13 +0200 Message-ID: <20250812172957.562134140@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250812172952.959106058@linuxfoundation.org> References: <20250812172952.959106058@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 31d7d67ba1274f42494256d52e86da80ed09f3cb ] rt->fib6_nsiblings can be read locklessly, add corresponding READ_ONCE() and WRITE_ONCE() annotations. Fixes: 66f5d6ce53e6 ("ipv6: replace rwlock with rcu and spinlock in fib6_table") Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20250725140725.3626540-5-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv6/ip6_fib.c | 20 +++++++++++++------- net/ipv6/route.c | 5 +++-- 2 files changed, 16 insertions(+), 9 deletions(-) diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 65702bddb21f..c44136cbbaa1 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -437,15 +437,17 @@ struct fib6_dump_arg { static int fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg) { enum fib_event_type fib_event = FIB_EVENT_ENTRY_REPLACE; + unsigned int nsiblings; int err; if (!rt || rt == arg->net->ipv6.fib6_null_entry) return 0; - if (rt->fib6_nsiblings) + nsiblings = READ_ONCE(rt->fib6_nsiblings); + if (nsiblings) err = call_fib6_multipath_entry_notifier(arg->nb, fib_event, rt, - rt->fib6_nsiblings, + nsiblings, arg->extack); else err = call_fib6_entry_notifier(arg->nb, fib_event, rt, @@ -1118,7 +1120,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, if (rt6_duplicate_nexthop(iter, rt)) { if (rt->fib6_nsiblings) - rt->fib6_nsiblings = 0; + WRITE_ONCE(rt->fib6_nsiblings, 0); if (!(iter->fib6_flags & RTF_EXPIRES)) return -EEXIST; if (!(rt->fib6_flags & RTF_EXPIRES)) @@ -1144,7 +1146,8 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, */ if (rt_can_ecmp && rt6_qualify_for_ecmp(iter)) - rt->fib6_nsiblings++; + WRITE_ONCE(rt->fib6_nsiblings, + rt->fib6_nsiblings + 1); } if (iter->fib6_metric > rt->fib6_metric) @@ -1194,7 +1197,8 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, fib6_nsiblings = 0; list_for_each_entry_safe(sibling, temp_sibling, &rt->fib6_siblings, fib6_siblings) { - sibling->fib6_nsiblings++; + WRITE_ONCE(sibling->fib6_nsiblings, + sibling->fib6_nsiblings + 1); BUG_ON(sibling->fib6_nsiblings != rt->fib6_nsiblings); fib6_nsiblings++; } @@ -1239,7 +1243,8 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, list_for_each_entry_safe(sibling, next_sibling, &rt->fib6_siblings, fib6_siblings) - sibling->fib6_nsiblings--; + WRITE_ONCE(sibling->fib6_nsiblings, + sibling->fib6_nsiblings - 1); WRITE_ONCE(rt->fib6_nsiblings, 0); list_del_rcu(&rt->fib6_siblings); rt6_multipath_rebalance(next_sibling); @@ -1952,7 +1957,8 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn, notify_del = true; list_for_each_entry_safe(sibling, next_sibling, &rt->fib6_siblings, fib6_siblings) - sibling->fib6_nsiblings--; + WRITE_ONCE(sibling->fib6_nsiblings, + sibling->fib6_nsiblings - 1); WRITE_ONCE(rt->fib6_nsiblings, 0); list_del_rcu(&rt->fib6_siblings); rt6_multipath_rebalance(next_sibling); diff --git a/net/ipv6/route.c b/net/ipv6/route.c index f180b7bc9f57..eb9e505f71f9 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5230,7 +5230,8 @@ static void ip6_route_mpath_notify(struct fib6_info *rt, */ rcu_read_lock(); - if ((nlflags & NLM_F_APPEND) && rt_last && rt_last->fib6_nsiblings) { + if ((nlflags & NLM_F_APPEND) && rt_last && + READ_ONCE(rt_last->fib6_nsiblings)) { rt = list_first_or_null_rcu(&rt_last->fib6_siblings, struct fib6_info, fib6_siblings); @@ -5763,7 +5764,7 @@ static int rt6_fill_node(struct net *net, struct sk_buff *skb, if (dst->lwtstate && lwtunnel_fill_encap(skb, dst->lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0) goto nla_put_failure; - } else if (rt->fib6_nsiblings) { + } else if (READ_ONCE(rt->fib6_nsiblings)) { struct fib6_info *sibling; struct nlattr *mp; -- 2.39.5