From: John Fastabend <john.r.fastabend@intel•com>
To: John Fastabend <john.fastabend@gmail•com>,
xiyou.wangcong@gmail•com, davem@davemloft•net,
eric.dumazet@gmail•com
Cc: netdev@vger•kernel.org, jhs@mojatatu•com
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 [thread overview]
Message-ID: <5417D7D0.3080803@intel.com> (raw)
In-Reply-To: <20140916024759.3010.24175.stgit@nitbit.x32>
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] <asn:4>*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] <asn:4>*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] <asn:4>*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 <john.r.fastabend@intel•com>
> ---
> 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
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>
next prev parent reply other threads:[~2014-09-16 6:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-16 2:47 [net-next PATCH 1/3] net: sched: fix unsued cpu variable John Fastabend
2014-09-16 2:48 ` [net-next PATCH 2/3] net: sched: cls_u32 add missing rcu_assign_pointer and annotation John Fastabend
2014-09-16 6:25 ` John Fastabend [this message]
2014-09-16 2:48 ` [net-next PATCH 3/3] net: sched: cls_cgroup fix possible memory leak of 'new' John Fastabend
2014-09-16 3:04 ` Cong Wang
2014-09-16 3:29 ` John Fastabend
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