From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:48716 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752497AbeBINlZ (ORCPT ); Fri, 9 Feb 2018 08:41:25 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paolo Abeni , Cong Wang , "David S. Miller" Subject: [PATCH 4.9 27/92] cls_u32: add missing RCU annotation. Date: Fri, 9 Feb 2018 14:38:56 +0100 Message-Id: <20180209133933.184130086@linuxfoundation.org> In-Reply-To: <20180209133931.211869118@linuxfoundation.org> References: <20180209133931.211869118@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paolo Abeni [ Upstream commit 058a6c033488494a6b1477b05fe8e1a16e344462 ] In a couple of points of the control path, n->ht_down is currently accessed without the required RCU annotation. The accesses are safe, but sparse complaints. Since we already held the rtnl lock, let use rtnl_dereference(). Fixes: a1b7c5fd7fe9 ("net: sched: add cls_u32 offload hooks for netdevs") Fixes: de5df63228fc ("net: sched: cls_u32 changes to knode must appear atomic to readers") Signed-off-by: Paolo Abeni Acked-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sched/cls_u32.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) --- a/net/sched/cls_u32.c +++ b/net/sched/cls_u32.c @@ -496,6 +496,7 @@ static void u32_clear_hw_hnode(struct tc static int u32_replace_hw_knode(struct tcf_proto *tp, struct tc_u_knode *n, u32 flags) { + struct tc_u_hnode *ht = rtnl_dereference(n->ht_down); struct net_device *dev = tp->q->dev_queue->dev; struct tc_cls_u32_offload u32_offload = {0}; struct tc_to_netdev offload; @@ -520,7 +521,7 @@ static int u32_replace_hw_knode(struct t offload.cls_u32->knode.sel = &n->sel; offload.cls_u32->knode.exts = &n->exts; if (n->ht_down) - offload.cls_u32->knode.link_handle = n->ht_down->handle; + offload.cls_u32->knode.link_handle = ht->handle; err = dev->netdev_ops->ndo_setup_tc(dev, tp->q->handle, tp->protocol, &offload); @@ -788,8 +789,9 @@ static void u32_replace_knode(struct tcf static struct tc_u_knode *u32_init_knode(struct tcf_proto *tp, struct tc_u_knode *n) { - struct tc_u_knode *new; + struct tc_u_hnode *ht = rtnl_dereference(n->ht_down); struct tc_u32_sel *s = &n->sel; + struct tc_u_knode *new; new = kzalloc(sizeof(*n) + s->nkeys*sizeof(struct tc_u32_key), GFP_KERNEL); @@ -807,11 +809,11 @@ static struct tc_u_knode *u32_init_knode new->fshift = n->fshift; new->res = n->res; new->flags = n->flags; - RCU_INIT_POINTER(new->ht_down, n->ht_down); + RCU_INIT_POINTER(new->ht_down, ht); /* bump reference count as long as we hold pointer to structure */ - if (new->ht_down) - new->ht_down->refcnt++; + if (ht) + ht->refcnt++; #ifdef CONFIG_CLS_U32_PERF /* Statistics may be incremented by readers during update