From patchwork Tue Nov 5 18:23:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Abeni X-Patchwork-Id: 840947 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 1A47C1E7C27 for ; Tue, 5 Nov 2024 18:24:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730831050; cv=none; b=Gn5vyktU7K5lLGc1Ks2DG2VYJll6HPksJhajct45mFIx2HqBRZMSIjXoTigH2N95HQTRmgYeg9L/6E0s4R8nv26IUKG3tIW4J4zeSXkwTIGJuxpcmVhOgOvEIqkFweG8u+CKtk7x/a/ENkRntCyHf+khcWVcNqt7H45XhEUf/SM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730831050; c=relaxed/simple; bh=CEjCyvXvJ/kGyO+gCOIAjc/shcY5Wcat2zi6BAVM/1I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PebuU7AK39AZePDW7VFRDpUdATQ64UWjQLmBZRWnrD0LADCsGllxf8NubnHsJBatNaZflHFr363NROv5cw2PXbgoL932SLdxiMamQtXIP7zXU+UGeXeVGVhJ0L+LBmtgPvTiUIfoMiQlBlmmKxb2YynHwe8XgoAKSO8uLfBdJGI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=UHxCPaP4; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="UHxCPaP4" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1730831048; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9nMzFaH7xhvOwU6njzW4m1dY8b7raVf0U5dhvj0ijxw=; b=UHxCPaP498sbndSxwSDDgKYC8M/Uhj2VM7MIHf7AFsra5Mes9vPMu7+z/UDvmMPWFNdGhI TT0tRPe5vL0/QjRwEiEBT/3NJNTrL9Evqm2GerHZLgN7jhpqPRoP5y1v67yB1EFGN1U0Af 0mBoAuI2PbBqxwus9T0RrZvolaIRYPQ= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-496-lwjcZruJMu6J3AHgI2rcKg-1; Tue, 05 Nov 2024 13:24:05 -0500 X-MC-Unique: lwjcZruJMu6J3AHgI2rcKg-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 3AE3F195395C; Tue, 5 Nov 2024 18:24:03 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.45.225.71]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id BE59C19560AA; Tue, 5 Nov 2024 18:23:59 +0000 (UTC) From: Paolo Abeni To: netdev@vger.kernel.org Cc: "David S. Miller" , David Ahern , Eric Dumazet , Jakub Kicinski , Simon Horman , Shuah Khan , linux-kselftest@vger.kernel.org Subject: [PATCH v2 net-next 1/2] ipv6: release nexthop on device removal Date: Tue, 5 Nov 2024 19:23:50 +0100 Message-ID: <604c45c188c609b732286b47ac2a451a40f6cf6d.1730828007.git.pabeni@redhat.com> In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 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 --- v1 -> v2: - dropped unintended whitespace change --- net/ipv6/route.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index d7ce5cf2017a..038c1eeef0be 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -374,6 +374,7 @@ static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev) { struct rt6_info *rt = dst_rt6_info(dst); struct inet6_dev *idev = rt->rt6i_idev; + struct fib6_info *from; if (idev && idev->dev != blackhole_netdev) { struct inet6_dev *blackhole_idev = in6_dev_get(blackhole_netdev); @@ -383,6 +384,8 @@ static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev) in6_dev_put(idev); } } + from = unrcu_pointer(xchg(&rt->from, NULL)); + fib6_info_release(from); } static bool __rt6_check_expired(const struct rt6_info *rt) @@ -1455,7 +1458,6 @@ static DEFINE_SPINLOCK(rt6_exception_lock); 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) @@ -1467,8 +1469,6 @@ static void rt6_remove_exception(struct rt6_exception_bucket *bucket, /* purge completely the exception to allow releasing the held resources: * some [sk] cache may keep the dst around for unlimited time */ - from = unrcu_pointer(xchg(&rt6_ex->rt6i->from, NULL)); - fib6_info_release(from); dst_dev_put(&rt6_ex->rt6i->dst); hlist_del_rcu(&rt6_ex->hlist);