From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794585861; b=dHhCJxcl+7klYn1C+k5d4hmpCQpy7rWugpduTFX4sAF+xBJNos/Yge/Cala8vl+vY9b2 VZDNHX7GD8Bw0c//mO+c4niTWZpyogJ+6vzDD6LDyQiFTIfTEPUE5ESzm4O/i8Ilz4uYb uN+HPNGrHlJG0hTmcjmh9WS7g4ygEyJlM/BZdTtu0ULmqystb17mVUVUSD2zdC2+v7Knh ht3P96jN8LcsQdMx8HLvZiU2cxCs3ikylzQeMOtSqbftPRuDbgb4TqlWYLIUVNYMFI1uY Su7ldaEbKjZJdJ0OTMmo6KQfR/VkWvhyZjCsyc+XJkkZnVumgg/+by7G0mCKnGkorog== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794585861; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=7c6kKL+eZO9M2MWtsjgRCkc1TSnZciAfNbqhaegDM3Y=; b=dsWv6e3U6inrUMMJUGECc4eTdciGlcJhTIYZMxLXQbUXV956pNPfTnleSpuB4XhBI8u3 YjiliHkLZGgMhD8JyupSuAeHYS/zk25cpLfA8WIW64EyKpRuqhKA8nPsJRgd8/5GsPlne M2oeRZ0opc8rXmxADA7vn1UJNiYunYL5a2obusq0X57N6cZWkxvKGEzMcuVIk15DSbEsb JxnvMU/1UqXKifaCvqJXjWF6Q4gdTtwLRzz1XErLguk35ruZ5WcLCZ4JKNoIenIK/eaNJ JFux7xLqDwghZuRy0tKBo0yKfr7UNs0ZhLwZSO37tNVd89dyoK8o3DTme++4ydUjEVQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=RJ6bNG8o; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 61786606BAB8; Fri, 13 Nov 2026 16:04:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=RJ6bNG8o Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0CD931F000C5; Fri, 13 Nov 2026 16:04:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794585861; bh=7c6kKL+eZO9M2MWtsjgRCkc1TSnZciAfNbqhaegDM3Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RJ6bNG8oHy2gJVYz/Icve8BPkGaeS2MhETX/yR6VKZvPOmKYwZevz21Jr4qGZrBaL 4ZFX7vWol+BV7vRzWUw4AnEpjCD+MBHY6erBu3g5GTAOGN6nCsMszzT0Iow9UEgDeO jOiLkKAkPOu1PSTYQ8wA08W+CLtpO/PK55LRyimU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sascha Frey , Ido Schimmel , Nikolay Aleksandrov , Paolo Abeni , Sasha Levin Subject: [PATCH 7.3 435/507] vxlan: Stop rejecting dynamic FDB entries with a nexthop ID Date: Fri, 13 Nov 2026 10:52:19 -0500 Message-ID: <20261113153811.481358820@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153753.358973689@linuxfoundation.org> References: <20261113153753.358973689@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ido Schimmel [ Upstream commit 7308ef8b4a6779a39f68d053c19b53a5c584a663 ] Commit 98fc57d16744 ("vxlan: reject dynamic fdb entries that reference a nexthop id") started rejecting FDB entries that point to FDB nexthops unless they are configured as "permanent" or "static". The intent was to prevent such entries from being aged out by vxlan_cleanup(), which runs without RTNL and can therefore race with other VXLAN devices that modify the same per-nexthop FDB list. However, FRR installs remote MACs that are behind a multihomed Ethernet Segment (EVPN-MH) as dynamic FDB entries that point to an FDB nexthop group. Since the above commit, these entries are rejected and traffic towards the corresponding MACs is flooded to all the remote VTEPs. These entries are also marked as externally learned ("extern_learn") and are therefore skipped by vxlan_cleanup(), but exempting externally learned entries from the checks is not enough: vxlan_cleanup() reads the state and flags of an entry without the hash lock, so an entry that is concurrently changed from dynamic and externally learned to static can still be aged out. Instead, remove the checks added by the above commit and make vxlan_cleanup() skip FDB entries that point to FDB nexthops. Such entries can only be configured from user space, cannot be learned and cannot roam, so there is no reason to age them out. The nexthop pointer of an FDB entry is set before the entry is linked and is only cleared after it was unlinked and an RCU grace period has passed, so it can be checked without the hash lock. Adjust the test cases added by the above commit and add a test case that checks that dynamic FDB entries that point to FDB nexthops are not aged out. Without the fix: # ./fib_nexthops.sh -t "ipv4_fdb_grp_fcnal ipv6_fdb_grp_fcnal" IPv4 fdb groups functional -------------------------- [...] TEST: Fdb mac add with nexthop group and dynamic state [FAIL] TEST: Fdb mac add with nexthop group and extern_learn [FAIL] TEST: Fdb mac without nexthop group aged out [ OK ] TEST: Fdb mac with nexthop group not aged out [FAIL] [...] IPv6 fdb groups functional -------------------------- [...] TEST: Fdb mac add with nexthop group and dynamic state [FAIL] TEST: Fdb mac add with nexthop group and extern_learn [FAIL] TEST: Fdb mac without nexthop group aged out [ OK ] TEST: Fdb mac with nexthop group not aged out [FAIL] [...] Tests passed: 44 Tests failed: 6 Tests skipped: 0 With the fix: # ./fib_nexthops.sh -t "ipv4_fdb_grp_fcnal ipv6_fdb_grp_fcnal" IPv4 fdb groups functional -------------------------- [...] TEST: Fdb mac add with nexthop group and dynamic state [ OK ] TEST: Fdb mac add with nexthop group and extern_learn [ OK ] TEST: Fdb mac without nexthop group aged out [ OK ] TEST: Fdb mac with nexthop group not aged out [ OK ] [...] IPv6 fdb groups functional -------------------------- [...] TEST: Fdb mac add with nexthop group and dynamic state [ OK ] TEST: Fdb mac add with nexthop group and extern_learn [ OK ] TEST: Fdb mac without nexthop group aged out [ OK ] TEST: Fdb mac with nexthop group not aged out [ OK ] [...] Tests passed: 50 Tests failed: 0 Tests skipped: 0 Fixes: 1274e1cc4226 ("vxlan: ecmp support for mac fdb entries") Fixes: 98fc57d16744 ("vxlan: reject dynamic fdb entries that reference a nexthop id") Cc: stable@vger.kernel.org Reported-by: Sascha Frey Closes: https://lore.kernel.org/netdev/20261028142928.GA8406@techfak.de/ Tested-by: Sascha Frey Signed-off-by: Ido Schimmel Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20261030133750.28668-1-idosch@nvidia.com Signed-off-by: Paolo Abeni [ idosch: fixed a small conflict in vxlan_fdb_add() and vxlan_cleanup() ] Signed-off-by: Ido Schimmel Signed-off-by: Sasha Levin --- drivers/net/vxlan/vxlan_core.c | 14 ++------ tools/testing/selftests/net/fib_nexthops.sh | 40 ++++++++++++++------- 2 files changed, 31 insertions(+), 23 deletions(-) diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c index 3390e341d1e58..7ecd73a5a3745 100644 --- a/drivers/net/vxlan/vxlan_core.c +++ b/drivers/net/vxlan/vxlan_core.c @@ -996,12 +996,6 @@ static int vxlan_fdb_update_existing(struct vxlan_dev *vxlan, return -EOPNOTSUPP; } - if (rcu_access_pointer(f->nh) && - !(state & (NUD_PERMANENT | NUD_NOARP))) { - NL_SET_ERR_MSG(extack, "Cannot make a nexthop fdb dynamic"); - return -EOPNOTSUPP; - } - /* Do not allow an externally learned entry to take over an entry added * by the user. */ @@ -1263,11 +1257,6 @@ static int vxlan_fdb_add(struct ndmsg *ndm, struct nlattr *tb[], if (err) return err; - if (nhid && !(ndm->ndm_state & (NUD_PERMANENT | NUD_NOARP))) { - NL_SET_ERR_MSG(extack, "A nexthop fdb cannot be dynamic"); - return -EINVAL; - } - if (vxlan->default_dst.remote_ip.sa.sa_family != ip.sa.sa_family) return -EAFNOSUPPORT; @@ -2887,6 +2876,9 @@ static void vxlan_cleanup(struct timer_list *t) if (f->flags & NTF_EXT_LEARNED) continue; + if (rcu_access_pointer(f->nh)) + continue; + timeout = READ_ONCE(f->updated) + vxlan->cfg.age_interval * HZ; if (time_before_eq(timeout, jiffies)) { spin_lock(&vxlan->hash_lock); diff --git a/tools/testing/selftests/net/fib_nexthops.sh b/tools/testing/selftests/net/fib_nexthops.sh index 431d7bed76224..adbec51917eb8 100755 --- a/tools/testing/selftests/net/fib_nexthops.sh +++ b/tools/testing/selftests/net/fib_nexthops.sh @@ -425,6 +425,14 @@ stop_ip_monitor() return $rc } +fdb_entry_aged() +{ + local mac=$1 + local dev=$2 + + ! $BRIDGE fdb get to $mac dev $dev self &> /dev/null +} + check_nexthop_fdb_support() { $IP nexthop help 2>&1 | grep -q fdb @@ -538,14 +546,18 @@ ipv6_fdb_grp_fcnal() log_test $? 0 "Fdb mac add with nexthop group and static state" run_cmd "$BRIDGE fdb add 02:02:00:00:00:16 dev vx10 nhid 102 self dynamic" - log_test $? 255 "Fdb mac add with nexthop group and dynamic state" + log_test $? 0 "Fdb mac add with nexthop group and dynamic state" + + run_cmd "$BRIDGE fdb add 02:02:00:00:00:17 dev vx10 nhid 102 self dynamic extern_learn" + log_test $? 0 "Fdb mac add with nexthop group and extern_learn" - run_cmd "$BRIDGE fdb add 02:02:00:00:00:17 dev vx10 nhid 102 self" - run_cmd "$BRIDGE fdb replace 02:02:00:00:00:17 dev vx10 dst 2001:db8:91::11 self dynamic" - log_test $? 255 "Fdb mac replace with nexthop group and dynamic state" + run_cmd "$IP link set dev vx10 up type vxlan ageing 1" + run_cmd "$BRIDGE fdb add 02:02:00:00:00:18 dev vx10 dst 2001:db8:91::11 self dynamic" + slowwait 20 fdb_entry_aged 02:02:00:00:00:18 vx10 + log_test $? 0 "Fdb mac without nexthop group aged out" - run_cmd "$BRIDGE fdb append 02:02:00:00:00:17 dev vx10 dst 2001:db8:91::11 self dynamic" - log_test $? 255 "Fdb mac append with nexthop group and dynamic state" + run_cmd "$BRIDGE fdb get to 02:02:00:00:00:16 dev vx10 self" + log_test $? 0 "Fdb mac with nexthop group not aged out" run_cmd "$IP -6 ro add 2001:db8:101::1/128 nhid 66" log_test $? 2 "Route add with fdb nexthop" @@ -688,14 +700,18 @@ ipv4_fdb_grp_fcnal() log_test $? 0 "Fdb mac add with nexthop group and static state" run_cmd "$BRIDGE fdb add 02:02:00:00:00:16 dev vx10 nhid 102 self dynamic" - log_test $? 255 "Fdb mac add with nexthop group and dynamic state" + log_test $? 0 "Fdb mac add with nexthop group and dynamic state" + + run_cmd "$BRIDGE fdb add 02:02:00:00:00:17 dev vx10 nhid 102 self dynamic extern_learn" + log_test $? 0 "Fdb mac add with nexthop group and extern_learn" - run_cmd "$BRIDGE fdb add 02:02:00:00:00:17 dev vx10 nhid 102 self" - run_cmd "$BRIDGE fdb replace 02:02:00:00:00:17 dev vx10 dst 10.0.0.3 self dynamic" - log_test $? 255 "Fdb mac replace with nexthop group and dynamic state" + run_cmd "$IP link set dev vx10 up type vxlan ageing 1" + run_cmd "$BRIDGE fdb add 02:02:00:00:00:18 dev vx10 dst 10.0.0.3 self dynamic" + slowwait 20 fdb_entry_aged 02:02:00:00:00:18 vx10 + log_test $? 0 "Fdb mac without nexthop group aged out" - run_cmd "$BRIDGE fdb append 02:02:00:00:00:17 dev vx10 dst 10.0.0.3 self dynamic" - log_test $? 255 "Fdb mac append with nexthop group and dynamic state" + run_cmd "$BRIDGE fdb get to 02:02:00:00:00:16 dev vx10 self" + log_test $? 0 "Fdb mac with nexthop group not aged out" run_cmd "$IP ro add 172.16.0.0/22 nhid 16" log_test $? 2 "Route add with fdb nexthop" -- 2.53.0