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 655261F75B3; Tue, 3 Dec 2024 15:10:06 +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=1733238606; cv=none; b=DD/8RA/BOrfEQ2OzRzV2FJJ4Uql/1X0g95VtTwqhl26Cbh/BqObWJuGxNH0JmtsaPO7a2v4i9P9feQL8GDf03UTRYxF3I6UHevyEYu97I0e2yjnVsrwJtl0OBZ5HPlIisgOy+SeNncugHrkUZtfla29l56fuKb9IS7DC/I+qCUY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733238606; c=relaxed/simple; bh=mkmWDhrRN/DOD7kKNqnbkoQZAOa6+15xzif9HBrQZgM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ccZls4vbDfMOq6dQB/y5eqMizw1rE6CoA2qFbld4/KR3jixW0pCMkIlaACV1hyRmVysYHkyzu5xq+Z4biSCSdKZ/3KPMLnqrcpz81vc0+sIVH9PvwQWS2YRT6/IUvx6kxpWUcGp7ZZDL8yuLUvEy4m0CMxriBAX3sUb4F/4Rc5g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=R1Qn/hwC; 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="R1Qn/hwC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1CB6C4CECF; Tue, 3 Dec 2024 15:10:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1733238606; bh=mkmWDhrRN/DOD7kKNqnbkoQZAOa6+15xzif9HBrQZgM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=R1Qn/hwCRZn9qeSBaZtg7kXu0bXzCFXQEeWK0PNENKInpLffjVOERNc6EpxRvBpM4 bLtMF/6hIfifGB/3MhlEdO2d3SA1I+FCfYd6TH5hDUZL6KS2Ug5ohV/FqXkdg6UDwA 6rP7DXjVjDqERLsB3YdpO1hqDLCJcFfPu1dY7Sh4= 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 6.11 334/817] ipv6: release nexthop on device removal Date: Tue, 3 Dec 2024 15:38:26 +0100 Message-ID: <20241203144008.856794950@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241203143955.605130076@linuxfoundation.org> References: <20241203143955.605130076@linuxfoundation.org> User-Agent: quilt/0.67 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 6.11-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 b4dcd8f3e7bab..606cdd87745a6 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); -- 2.43.0