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 32B4825393F; Tue, 29 Apr 2025 17:51:05 +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=1745949065; cv=none; b=IPqbIYVUlKIa4o3VP4cgkjAyph4pV8PBhfa1tSnfIpWGbJGUdrY1sR247VMZWd4rCg31rGQWHBssMdf4f6LpR7Kp9yTu5762ng8izlyzqK8wm+DAdcX3bKCXz6KjJE/PpYWPohgFiSpYkYUOiCKpXF/GDhFE1aaWe+6Ht1Vhuyw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745949065; c=relaxed/simple; bh=wTD+AZaHWYLgycpG0MmeHb4DKma3YNjtiJr44/QqZzQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uU+sscHEcX3q7PNXVchkIWBjF1l32fQyPggUcU54T6HnThdUnRQRaBNlWQauaAyiX4DepPk/PpN/yE7hncxEQZ1rFQlIsM0VyqW6u8SnQ1UvF4e+6dgI1e+Y93Vi9/Wb7GnmnzRJtNDMm63P51FFm9yqzUDyt7OU4bmn5frgot8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ybAeFssN; 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="ybAeFssN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B7FA3C4CEE9; Tue, 29 Apr 2025 17:51:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745949065; bh=wTD+AZaHWYLgycpG0MmeHb4DKma3YNjtiJr44/QqZzQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ybAeFssNLnS82sccIpzkLtyTUSgAtvSKxRfJAtMxv1Btm1GYlt0I9WjOxPstAP4Kf snE933NFznaCtXRyJqItasyxcjwH3PFJnfDLm8GZvK3dq/BiCZD5ScKZbwWyNn9jY9 ewcdqBnwD4YyMzzZ2yH0tFgBPJmJ/imXw3gCWzjk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Paolo Abeni , Eric Dumazet , David Ahern , Jakub Kicinski , Harshit Mogalapalli Subject: [PATCH 5.15 203/373] ipv6: release nexthop on device removal Date: Tue, 29 Apr 2025 18:41:20 +0200 Message-ID: <20250429161131.514501753@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250429161123.119104857@linuxfoundation.org> References: <20250429161123.119104857@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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paolo Abeni [ Upstream commit eb02688c5c45c3e7af7e71f036a7144f5639cbfe ] The CI is hitting some aperiodic hangup at device removal time in the pmtu.sh self-test: unregister_netdevice: waiting for veth_A-R1 to become free. Usage count = 6 ref_tracker: veth_A-R1@ffff888013df15d8 has 1/5 users at dst_init+0x84/0x4a0 dst_alloc+0x97/0x150 ip6_dst_alloc+0x23/0x90 ip6_rt_pcpu_alloc+0x1e6/0x520 ip6_pol_route+0x56f/0x840 fib6_rule_lookup+0x334/0x630 ip6_route_output_flags+0x259/0x480 ip6_dst_lookup_tail.constprop.0+0x5c2/0x940 ip6_dst_lookup_flow+0x88/0x190 udp_tunnel6_dst_lookup+0x2a7/0x4c0 vxlan_xmit_one+0xbde/0x4a50 [vxlan] vxlan_xmit+0x9ad/0xf20 [vxlan] dev_hard_start_xmit+0x10e/0x360 __dev_queue_xmit+0xf95/0x18c0 arp_solicit+0x4a2/0xe00 neigh_probe+0xaa/0xf0 While the first suspect is the dst_cache, explicitly tracking the dst owing the last device reference via probes proved such dst is held by the nexthop in the originating fib6_info. Similar to commit f5b51fe804ec ("ipv6: route: purge exception on removal"), we need to explicitly release the originating fib info when disconnecting a to-be-removed device from a live ipv6 dst: move the fib6_info cleanup into ip6_dst_ifdown(). Tested running: ./pmtu.sh cleanup_ipv6_exception in a tight loop for more than 400 iterations with no spat, running an unpatched kernel I observed a splat every ~10 iterations. Fixes: f88d8ea67fbd ("ipv6: Plumb support for nexthop object in a fib6_info") Signed-off-by: Paolo Abeni Reviewed-by: Eric Dumazet Reviewed-by: David Ahern Link: https://patch.msgid.link/604c45c188c609b732286b47ac2a451a40f6cf6d.1730828007.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski (cherry picked from commit eb02688c5c45c3e7af7e71f036a7144f5639cbfe) [Harshit: Resolved conflict due to missing commit: e5f80fcf869a ("ipv6: give an IPv6 dev to blackhole_netdev") and commit: b4cb4a1391dc ("net: use unrcu_pointer() helper") in linux-5.15.y] Signed-off-by: Harshit Mogalapalli Signed-off-by: Greg Kroah-Hartman --- net/ipv6/route.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -377,6 +377,7 @@ static void ip6_dst_ifdown(struct dst_en struct inet6_dev *idev = rt->rt6i_idev; struct net_device *loopback_dev = dev_net(dev)->loopback_dev; + struct fib6_info *from; if (idev && idev->dev != loopback_dev) { struct inet6_dev *loopback_idev = in6_dev_get(loopback_dev); @@ -385,6 +386,8 @@ static void ip6_dst_ifdown(struct dst_en in6_dev_put(idev); } } + from = xchg((__force struct fib6_info **)&rt->from, NULL); + fib6_info_release(from); } static bool __rt6_check_expired(const struct rt6_info *rt) @@ -1443,7 +1446,6 @@ static DEFINE_SPINLOCK(rt6_exception_loc static void rt6_remove_exception(struct rt6_exception_bucket *bucket, struct rt6_exception *rt6_ex) { - struct fib6_info *from; struct net *net; if (!bucket || !rt6_ex) @@ -1455,8 +1457,6 @@ static void rt6_remove_exception(struct /* purge completely the exception to allow releasing the held resources: * some [sk] cache may keep the dst around for unlimited time */ - from = xchg((__force struct fib6_info **)&rt6_ex->rt6i->from, NULL); - fib6_info_release(from); dst_dev_put(&rt6_ex->rt6i->dst); hlist_del_rcu(&rt6_ex->hlist);