From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Fastabend Subject: Re: [net-next PATCH 2/3] net: sched: cls_u32 add missing rcu_assign_pointer and annotation Date: Mon, 15 Sep 2014 23:25:20 -0700 Message-ID: <5417D7D0.3080803@intel.com> References: <20140916024729.3010.47421.stgit@nitbit.x32> <20140916024759.3010.24175.stgit@nitbit.x32> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, jhs@mojatatu.com To: John Fastabend , xiyou.wangcong@gmail.com, davem@davemloft.net, eric.dumazet@gmail.com Return-path: Received: from mga09.intel.com ([134.134.136.24]:48404 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750813AbaIPGZs (ORCPT ); Tue, 16 Sep 2014 02:25:48 -0400 In-Reply-To: <20140916024759.3010.24175.stgit@nitbit.x32> Sender: netdev-owner@vger.kernel.org List-ID: On 09/15/2014 07:48 PM, John Fastabend wrote: > Add missing rcu_assign_pointer and missing annotation for ht_up > in cls_u32.c > > Caught by kbuild bot, > >>> net/sched/cls_u32.c:378:36: sparse: incorrect type in initializer (different address spaces) > net/sched/cls_u32.c:378:36: expected struct tc_u_hnode *ht > net/sched/cls_u32.c:378:36: got struct tc_u_hnode [noderef] *ht_up >>> net/sched/cls_u32.c:610:54: sparse: incorrect type in argument 4 (different address spaces) > net/sched/cls_u32.c:610:54: expected struct tc_u_hnode *ht > net/sched/cls_u32.c:610:54: got struct tc_u_hnode [noderef] *ht_up >>> net/sched/cls_u32.c:684:18: sparse: incorrect type in assignment (different address spaces) > net/sched/cls_u32.c:684:18: expected struct tc_u_hnode [noderef] *ht_up > net/sched/cls_u32.c:684:18: got struct tc_u_hnode *[assigned] ht >>> net/sched/cls_u32.c:359:18: sparse: dereference of noderef expression > > Signed-off-by: John Fastabend > --- > net/sched/cls_u32.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c > index 8cffe5a..19b2808 100644 > --- a/net/sched/cls_u32.c > +++ b/net/sched/cls_u32.c > @@ -375,7 +375,7 @@ static int u32_delete_key(struct tcf_proto *tp, struct tc_u_knode *key) > { > struct tc_u_knode __rcu **kp; > struct tc_u_knode *pkp; > - struct tc_u_hnode *ht = key->ht_up; > + struct tc_u_hnode *ht = rtnl_dereference(key->ht_up); > > if (ht) { > kp = &ht->ht[TC_U32_HASH(key->handle)]; > @@ -607,7 +607,8 @@ static int u32_change(struct net *net, struct sk_buff *in_skb, > if (TC_U32_KEY(n->handle) == 0) > return -EINVAL; > > - return u32_set_parms(net, tp, base, n->ht_up, n, tb, > + return u32_set_parms(net, tp, base, > + rtnl_dereference(n->ht_up), n, tb, > tca[TCA_RATE], ovr); > } > > @@ -681,7 +682,7 @@ static int u32_change(struct net *net, struct sk_buff *in_skb, > #endif > > memcpy(&n->sel, s, sizeof(*s) + s->nkeys*sizeof(struct tc_u32_key)); > - n->ht_up = ht; > + rcu_assign_pointer(n->ht_up, ht); also believe this should be RCU_INIT_POINTER() the rcu_assign_pointer() to attach n to the hash table happens below so there are no concurrent readers until after the assign. however while reviewing this I realize there is a 'copy'/'update' pattern I missed in the u32_set_parms case when the classid and ifindex is changed. So a fix coming for that shortly. > n->handle = handle; > n->fshift = s->hmask ? ffs(ntohl(s->hmask)) - 1 : 0; > tcf_exts_init(&n->exts, TCA_U32_ACT, TCA_U32_POLICE); > > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >