From patchwork Thu Feb 21 05:49:39 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joel Fernandes X-Patchwork-Id: 1045766 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=joelfernandes.org Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="jT740G6e"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 444k8d2nx6z9s2R for ; Thu, 21 Feb 2019 16:50:25 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726779AbfBUFuD (ORCPT ); Thu, 21 Feb 2019 00:50:03 -0500 Received: from mail-qk1-f195.google.com ([209.85.222.195]:36473 "EHLO mail-qk1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726706AbfBUFuB (ORCPT ); Thu, 21 Feb 2019 00:50:01 -0500 Received: by mail-qk1-f195.google.com with SMTP id o125so3618690qkf.3 for ; Wed, 20 Feb 2019 21:50:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=JmLFpdRORBxQq944X6ow6jxn2Py1BtKo1o+DDQDbcPs=; b=jT740G6evoueaiJkbiGaGk2LjNX0z7MTAZi+fD2cpXIP210C+G4HEXamwzwB9f3j3n okdYQ422tOGTD2Sxn/0g/EyMYJJk0CzjHVDJh5+fUmQcBDwYkvWB18jKitux3eahODAo 2GIame4vikPR+xBuFaIgPHpPxTizicTNgU7WU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=JmLFpdRORBxQq944X6ow6jxn2Py1BtKo1o+DDQDbcPs=; b=eyKaqxE4MB+1FQ47tGWnqJ1JBN/Ur38caGRs0QUxwna2KVH2Zi0QjXmE3ZB2Dhws7P tux8R/+LjzRabbLsNZOgiQd00sx3XqZwbxcbJq/zKN4C0C2f/naLYRusmwBxdK2wyunZ sA1NdELPCx+jrzskgRH60TPbqyDHH/sVnNc2oMf9+wWCL9WMKKjS/ek0Xk2OOwkkjplO Z1jzcrWW8+3Myto6oC8MDRcaf0EmQ6qJK5uWwAGpGNLRvltXxI4N/cDlqPT1YA/5VYMb kHXyrC+L3OZs8DQqKcrjSpe+OGl7SyAiitIzNdoUNMPCCvlMaH/nWAiHj6gPwpYCik+V Q1jQ== X-Gm-Message-State: AHQUAuZyAyTKxzxZ/jc2d9Sk4yCHuwjIdMgvn1FVMiB51tS17RKLQz2s iV4dzXoyL1IM843WHKXIVMvCYA== X-Google-Smtp-Source: AHgI3IbOR4CRoe9MkfK2GQWb1kgEoC51CJYPHhkELH+l4iSnuB0HTltkfM39dpwbfZwR6vOy5FGzWg== X-Received: by 2002:a37:8d01:: with SMTP id p1mr28226874qkd.91.1550728200127; Wed, 20 Feb 2019 21:50:00 -0800 (PST) Received: from joelaf.cam.corp.google.com ([2620:0:1004:1100:cca9:fccc:8667:9bdc]) by smtp.gmail.com with ESMTPSA id k185sm11561219qkd.62.2019.02.20.21.49.58 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Feb 2019 21:49:59 -0800 (PST) From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: "Joel Fernandes (Google)" , Alexei Starovoitov , Christian Brauner , Daniel Borkmann , David Ahern , "David S. Miller" , Ido Schimmel , Ingo Molnar , intel-wired-lan@lists.osuosl.org (moderated list:INTEL ETHERNET DRIVERS), Jakub Kicinski , Jeff Kirsher , Jesper Dangaard Brouer , John Fastabend , Josh Triplett , keescook@chromium.org, Lai Jiangshan , Martin KaFai Lau , Mathieu Desnoyers , netdev@vger.kernel.org, "Paul E. McKenney" , Peter Zijlstra , rcu@vger.kernel.org, Song Liu , Steven Rostedt , xdp-newbies@vger.kernel.org, Yonghong Song Subject: [PATCH RFC 2/5] ixgbe: Fix incorrect RCU API usage Date: Thu, 21 Feb 2019 00:49:39 -0500 Message-Id: <20190221054942.132388-3-joel@joelfernandes.org> X-Mailer: git-send-email 2.21.0.rc0.258.g878e2cd30e-goog In-Reply-To: <20190221054942.132388-1-joel@joelfernandes.org> References: <20190221054942.132388-1-joel@joelfernandes.org> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Recently, I added an RCU annotation check in rcu_assign_pointer. This caused a sparse error to be reported by the ixgbe driver. Further looking, it seems the adapter->xdp_prog pointer is not annotated with __rcu. Annonating it fixed the error, but caused a bunch of other warnings. This patch tries to fix all warnings by using RCU API properly. This makes sense to do because not using RCU properly can result in various hard to find bugs. This is a best effort fix and is only build tested. The sparse errors and warnings go away with the change. I request maintainers / developers in this area to test it properly. Signed-off-by: Joel Fernandes (Google) --- drivers/net/ethernet/intel/ixgbe/ixgbe.h | 4 ++-- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 17 ++++++++++++----- 2 files changed, 14 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h index 08d85e336bd4..3b14daf27516 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h @@ -311,7 +311,7 @@ struct ixgbe_ring { struct ixgbe_ring *next; /* pointer to next ring in q_vector */ struct ixgbe_q_vector *q_vector; /* backpointer to host q_vector */ struct net_device *netdev; /* netdev ring belongs to */ - struct bpf_prog *xdp_prog; + struct bpf_prog __rcu *xdp_prog; struct device *dev; /* device for DMA mapping */ void *desc; /* descriptor ring memory */ union { @@ -560,7 +560,7 @@ struct ixgbe_adapter { unsigned long active_vlans[BITS_TO_LONGS(VLAN_N_VID)]; /* OS defined structs */ struct net_device *netdev; - struct bpf_prog *xdp_prog; + struct bpf_prog __rcu *xdp_prog; struct pci_dev *pdev; struct mii_bus *mii_bus; diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index daff8183534b..6aa59bb13a14 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -2199,7 +2199,7 @@ static struct sk_buff *ixgbe_run_xdp(struct ixgbe_adapter *adapter, u32 act; rcu_read_lock(); - xdp_prog = READ_ONCE(rx_ring->xdp_prog); + xdp_prog = rcu_dereference(rx_ring->xdp_prog); if (!xdp_prog) goto xdp_out; @@ -6547,7 +6547,7 @@ int ixgbe_setup_rx_resources(struct ixgbe_adapter *adapter, rx_ring->queue_index) < 0) goto err; - rx_ring->xdp_prog = adapter->xdp_prog; + rcu_assign_pointer(rx_ring->xdp_prog, adapter->xdp_prog); return 0; err: @@ -10246,7 +10246,10 @@ static int ixgbe_xdp_setup(struct net_device *dev, struct bpf_prog *prog) if (nr_cpu_ids > MAX_XDP_QUEUES) return -ENOMEM; - old_prog = xchg(&adapter->xdp_prog, prog); + rcu_read_lock(); + old_prog = rcu_dereference(adapter->xdp_prog); + rcu_assign_pointer(adapter->xdp_prog, prog); + rcu_read_unlock(); /* If transitioning XDP modes reconfigure rings */ if (!!prog != !!old_prog) { @@ -10271,13 +10274,17 @@ static int ixgbe_xdp_setup(struct net_device *dev, struct bpf_prog *prog) static int ixgbe_xdp(struct net_device *dev, struct netdev_bpf *xdp) { struct ixgbe_adapter *adapter = netdev_priv(dev); + struct bpf_prog *prog; switch (xdp->command) { case XDP_SETUP_PROG: return ixgbe_xdp_setup(dev, xdp->prog); case XDP_QUERY_PROG: - xdp->prog_id = adapter->xdp_prog ? - adapter->xdp_prog->aux->id : 0; + rcu_read_lock(); + prog = rcu_dereference(adapter->xdp_prog); + xdp->prog_id = prog ? prog->aux->id : 0; + rcu_read_unlock(); + return 0; case XDP_QUERY_XSK_UMEM: return ixgbe_xsk_umem_query(adapter, &xdp->xsk.umem,