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 0A82853A7; Fri, 6 Dec 2024 15:03:36 +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=1733497416; cv=none; b=Kd79IuP6Hw5DgH0N5mn1UGfhKet71aAQqwQ+o7X0IDms89d7bL0ebV63j3mhQ5zzqsDoL1Zta81bMDUEIcZJj8BjgqeKaa1FF4O1juV7p8gtdcI15VS3Z5OpZNJBl51wiMw3fhE7dfp9JZ6B+6CvrD14ZTVzB2wT04wbUL7HlVk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733497416; c=relaxed/simple; bh=QLtpHCB8lSaToy/l1MS4HBz1yzt82sbyOOaEUxjps9c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HSVxrrjFmyOyyIfKgHrW7NTttGxhQL7bc1or+YUZUpL0ZjD9qPGBtOszxApbgkDWhfG6rz/I9yy4B1mWcnlHNHRqhTvJw+ZkkHS3w5Bsdcx+WiGSCaHqKomUHWniPDJXpX8XfcjqydpocmZcPrrf8Er/xo+LXroeHYKVq33IYOE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DtS6ajQo; 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="DtS6ajQo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D56AC4CEDC; Fri, 6 Dec 2024 15:03:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1733497415; bh=QLtpHCB8lSaToy/l1MS4HBz1yzt82sbyOOaEUxjps9c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DtS6ajQo+VhOYjfnltqIPA8G4vJBlqIeTypwRbwb1APCC8RWE1A0+jbQci/OmW2Pa wJ2oVn+9vtCRYx9luDmfpORcwN5IgaMWx9MCl2ETFql/T4C53jGCniRpZMDGR9YCqD zVn9t17U49+FYZow79wRzduZIqECkJM/JgpAZE14= 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 , Sasha Levin Subject: [PATCH 6.6 244/676] ipv6: release nexthop on device removal Date: Fri, 6 Dec 2024 15:31:03 +0100 Message-ID: <20241206143702.862224624@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241206143653.344873888@linuxfoundation.org> References: <20241206143653.344873888@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-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 Signed-off-by: Sasha Levin --- 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 341a42c2d6f14..e320dfa7fe7fc 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -376,6 +376,7 @@ static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev) { struct rt6_info *rt = (struct 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); @@ -385,6 +386,8 @@ 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) @@ -1447,7 +1450,6 @@ 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) @@ -1459,8 +1461,6 @@ 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); -- 2.43.0