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=1794590525; b=dSnaCJ6LUlYCrCX1S4AX1Rr2xw4N/cAAjmhbf86JnM3LalA631M1O+ePUs5ix7nqJ/3y I2RQbV2s6VUuI19fPlPvuZDW2La7+VBmd3ya9cP/BN8a70YAASNM1/2b09KrN7V4N/teg z5GIFJanRBXgCqECrYMg4i9qaeCvmTXajRAJJT0C8E9qjDMiMM33fzaNPm/sWwdARcdGe 8mlCcvFy59WwcteU28FIruw4lNrS2cnnhE4PEwuYgHcGsYVuhwVOvfPl1Nj8MiYPGLNnw VZYTkLfJEWsYgzwa2IXRPoY8BcLeMKKcddGVD3xyvFi4VPcv1v4qQzTLKMcDjT2sEOQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794590525; 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=mljwpqVNVctO7Z5Z+M25HdBYBcAHOZ0vW8guwEj5K8s=; b=jEwHt6//dON3nwURNyAbMMEvXm0myvCiMPXP8WTO3bkj/3zyzjuiilr0B/3WRIigxllZ gicUryC7eac6Hrm2dXXn1Mkwkp+qHjGlzshBtZ5vCOK5sHfPAYkL6H2bzorNkighSzx1L /4i5tChjE9bu2/TbYZT2ER9kAsiU8i/G7kxjZumqCpotc7a7belprP3PbRCBxfFJALBov uQ25EbpZasXzJxEwxnPn/ATvCG6OGVNPCiWYgrWgKuj43P9OXQKcfZX8kE+UmUpc/ySpZ So2F4nB+944ztrNeM96y+B43gBoUMO9G9lWtpNd07veJDKScbiubEGbwdAN4Ob/kiFw== 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=0c+J8Oxr; 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 10B966073233; Fri, 13 Nov 2026 17:22:05 +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=0c+J8Oxr Received: by smtp.kernel.org (Postfix) with ESMTPSA id B01B11F000C4; Fri, 13 Nov 2026 17:22:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794590524; bh=mljwpqVNVctO7Z5Z+M25HdBYBcAHOZ0vW8guwEj5K8s=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=0c+J8Oxr88HLyBPQEz0r4EJzyxyjZx1AUpoa/3RxPEz+myFpxoMqsxo9XBEUbrYf/ F1emlAFUtFlh/ghXiXD4Y5LTZ7KYWs5+wDLERKEd6QDswQOVox8W4YYr9SYu5rzX5w NFTkBrzArZTNuCh1OGZB8yYA0qDlZmOLW/SGDhjc= 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 6.18 469/686] vxlan: Stop rejecting dynamic FDB entries with a nexthop ID Date: Fri, 13 Nov 2026 10:50:02 -0500 Message-ID: <20261113153836.790974902@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153820.902362109@linuxfoundation.org> References: <20261113153820.902362109@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-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 580fdec50bd59..090d50b163816 100644 --- a/drivers/net/vxlan/vxlan_core.c +++ b/drivers/net/vxlan/vxlan_core.c @@ -997,12 +997,6 @@ 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. */ @@ -1264,11 +1258,6 @@ 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; @@ -2889,6 +2878,9 @@ 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 7e450fb9d65b0..db65dd4abd3f7 100755 --- a/tools/testing/selftests/net/fib_nexthops.sh +++ b/tools/testing/selftests/net/fib_nexthops.sh @@ -423,6 +423,14 @@ 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 @@ -527,14 +535,18 @@ 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" @@ -641,14 +653,18 @@ 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