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 1F6A52C11D6 for ; Sun, 12 Apr 2026 16:58:32 +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=1776013113; cv=none; b=jsVqmC8QEQ4tH2aOeJVyBo2JKye2IUcl833WRW0SmyNgtSqF0C7VdVJmiWK+YxY8Bl0UDafeTxnBr6/HdSXuP98pZ4OLUr4PdvfhDKusNvCBL6fawmQ3PAlF6qrInhwRfrAHNl619MFienFUINsKXpf4WHcExwIYe2k0UWDBrl0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776013113; c=relaxed/simple; bh=5y0VgwX2/xSrjC2Qmj/NCeLj5lTCJvSdnJb2YwlFhU0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cvebQcjaijV4T522QmP12H/px/jZ1iC6U5p//SxDsVthRcN4rwd7lyFlQ2rkAmIOoT7rO9Vbn+PHcHsbMyXtqPhtiV+kVr1AIhChVuPa+PM4AAkVyXaoMi3finC1eeJNs7JPhnFVOgWf0F16kHeRzx+RoiduXUW9lhbatpA8W4A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WKuXnAzG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WKuXnAzG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1F41EC19424; Sun, 12 Apr 2026 16:58:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776013112; bh=5y0VgwX2/xSrjC2Qmj/NCeLj5lTCJvSdnJb2YwlFhU0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WKuXnAzGKnxlqN4ua+EBKMUwdIlP+9zMVRBWsxoPfYKOfXUpugNV1aI51IEgLtUDq 1oqfcjL5zF3TR0jof918E5YTVvCIbiCenwYmCOCL+GPNCpMhwKZXYgbPuHbjtSXe/B VBvc4MewjX2JsowiWS4Ui/hH9vTUm3rMvA3OdKpNA2oY6+hxBDHzm/u+6oXTDcRb6o p4bJDKGpm//kgx023EJo7F+Vw6qb6TAK4Ej+8CI0zNM23PKNvydHb/zv6VyoEjEE+e VM5gBazWv4IRqndKdVcQAeaew84VaJGIzyQZEO46Daf0h2JMYZrlssvBOBH0T48B6i vcH16s4lhYqaA== From: Sasha Levin To: stable@vger.kernel.org Cc: Andrea Mayer , Nicolas Dichtel , Justin Iurman , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6.y] seg6: separate dst_cache for input and output paths in seg6 lwtunnel Date: Sun, 12 Apr 2026 12:58:30 -0400 Message-ID: <20260412165830.2349698-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026041203-cleft-overpower-d9e5@gregkh> References: <2026041203-cleft-overpower-d9e5@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Andrea Mayer [ Upstream commit c3812651b522fe8437ebb7063b75ddb95b571643 ] The seg6 lwtunnel uses a single dst_cache per encap route, shared between seg6_input_core() and seg6_output_core(). These two paths can perform the post-encap SID lookup in different routing contexts (e.g., ip rules matching on the ingress interface, or VRF table separation). Whichever path runs first populates the cache, and the other reuses it blindly, bypassing its own lookup. Fix this by splitting the cache into cache_input and cache_output, so each path maintains its own cached dst independently. Fixes: 6c8702c60b88 ("ipv6: sr: add support for SRH encapsulation and injection with lwtunnels") Cc: stable@vger.kernel.org Signed-off-by: Andrea Mayer Reviewed-by: Nicolas Dichtel Reviewed-by: Justin Iurman Link: https://patch.msgid.link/20260404004405.4057-2-andrea.mayer@uniroma2.it Signed-off-by: Jakub Kicinski [ added missing dst reference loop guard in seg6_output_core() ] Signed-off-by: Sasha Levin --- net/ipv6/seg6_iptunnel.c | 41 +++++++++++++++++++++++++++------------- 1 file changed, 28 insertions(+), 13 deletions(-) diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c index c44e4c0824e0d..50bc05b853291 100644 --- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -48,7 +48,8 @@ static size_t seg6_lwt_headroom(struct seg6_iptunnel_encap *tuninfo) } struct seg6_lwt { - struct dst_cache cache; + struct dst_cache cache_input; + struct dst_cache cache_output; struct seg6_iptunnel_encap tuninfo[]; }; @@ -486,7 +487,7 @@ static int seg6_input_core(struct net *net, struct sock *sk, slwt = seg6_lwt_lwtunnel(lwtst); local_bh_disable(); - dst = dst_cache_get(&slwt->cache); + dst = dst_cache_get(&slwt->cache_input); local_bh_enable(); err = seg6_do_srh(skb, dst); @@ -500,7 +501,7 @@ static int seg6_input_core(struct net *net, struct sock *sk, /* cache only if we don't create a dst reference loop */ if (!dst->error && lwtst != dst->lwtstate) { local_bh_disable(); - dst_cache_set_ip6(&slwt->cache, dst, + dst_cache_set_ip6(&slwt->cache_input, dst, &ipv6_hdr(skb)->saddr); local_bh_enable(); } @@ -560,7 +561,7 @@ static int seg6_output_core(struct net *net, struct sock *sk, slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate); local_bh_disable(); - dst = dst_cache_get(&slwt->cache); + dst = dst_cache_get(&slwt->cache_output); local_bh_enable(); err = seg6_do_srh(skb, dst); @@ -585,9 +586,12 @@ static int seg6_output_core(struct net *net, struct sock *sk, goto drop; } - local_bh_disable(); - dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr); - local_bh_enable(); + /* cache only if we don't create a dst reference loop */ + if (orig_dst->lwtstate != dst->lwtstate) { + local_bh_disable(); + dst_cache_set_ip6(&slwt->cache_output, dst, &fl6.saddr); + local_bh_enable(); + } err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); if (unlikely(err)) @@ -694,11 +698,13 @@ static int seg6_build_state(struct net *net, struct nlattr *nla, slwt = seg6_lwt_lwtunnel(newts); - err = dst_cache_init(&slwt->cache, GFP_ATOMIC); - if (err) { - kfree(newts); - return err; - } + err = dst_cache_init(&slwt->cache_input, GFP_ATOMIC); + if (err) + goto err_free_newts; + + err = dst_cache_init(&slwt->cache_output, GFP_ATOMIC); + if (err) + goto err_destroy_input; memcpy(&slwt->tuninfo, tuninfo, tuninfo_len); @@ -713,11 +719,20 @@ static int seg6_build_state(struct net *net, struct nlattr *nla, *ts = newts; return 0; + +err_destroy_input: + dst_cache_destroy(&slwt->cache_input); +err_free_newts: + kfree(newts); + return err; } static void seg6_destroy_state(struct lwtunnel_state *lwt) { - dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache); + struct seg6_lwt *slwt = seg6_lwt_lwtunnel(lwt); + + dst_cache_destroy(&slwt->cache_input); + dst_cache_destroy(&slwt->cache_output); } static int seg6_fill_encap_info(struct sk_buff *skb, -- 2.53.0