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| author | Eric Dumazet <edumazet@google.com> | 2018-04-17 18:11:44 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-04-18 23:19:39 -0400 |
| commit | 415787d7799f4fccbe8d49cb0b8e5811be6b0389 (patch) | |
| tree | a765037e30cfc5bde6925be6a633920edc5f7b70 | |
| parent | 0dcec221dd39d4d48fe6b22b4cacf2f49b95ffa0 (diff) | |
| download | linux-415787d7799f4fccbe8d49cb0b8e5811be6b0389.tar.bz2 | |
ipv6: frags: fix a lockdep false positive
lockdep does not know that the locks used by IPv4 defrag
and IPv6 reassembly units are of different classes.
It complains because of following chains :
1) sch_direct_xmit() (lock txq->_xmit_lock)
dev_hard_start_xmit()
xmit_one()
dev_queue_xmit_nit()
packet_rcv_fanout()
ip_check_defrag()
ip_defrag()
spin_lock() (lock frag queue spinlock)
2) ip6_input_finish()
ipv6_frag_rcv() (lock frag queue spinlock)
ip6_frag_queue()
icmpv6_param_prob() (lock txq->_xmit_lock at some point)
We could add lockdep annotations, but we also can make sure IPv6
calls icmpv6_param_prob() only after the release of the frag queue spinlock,
since this naturally makes frag queue spinlock a leaf in lock hierarchy.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv6/reassembly.c | 23 |
1 files changed, 12 insertions, 11 deletions
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c index 2cdf3dcf8c2c..b939b94e7e91 100644 --- a/net/ipv6/reassembly.c +++ b/net/ipv6/reassembly.c @@ -163,7 +163,8 @@ fq_find(struct net *net, __be32 id, const struct ipv6hdr *hdr, int iif) } static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, - struct frag_hdr *fhdr, int nhoff) + struct frag_hdr *fhdr, int nhoff, + u32 *prob_offset) { struct sk_buff *prev, *next; struct net_device *dev; @@ -179,11 +180,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1))); if ((unsigned int)end > IPV6_MAXPLEN) { - __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev), - IPSTATS_MIB_INHDRERRORS); - icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, - ((u8 *)&fhdr->frag_off - - skb_network_header(skb))); + *prob_offset = (u8 *)&fhdr->frag_off - skb_network_header(skb); return -1; } @@ -214,10 +211,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, /* RFC2460 says always send parameter problem in * this case. -DaveM */ - __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev), - IPSTATS_MIB_INHDRERRORS); - icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, - offsetof(struct ipv6hdr, payload_len)); + *prob_offset = offsetof(struct ipv6hdr, payload_len); return -1; } if (end > fq->q.len) { @@ -519,15 +513,22 @@ static int ipv6_frag_rcv(struct sk_buff *skb) iif = skb->dev ? skb->dev->ifindex : 0; fq = fq_find(net, fhdr->identification, hdr, iif); if (fq) { + u32 prob_offset = 0; int ret; spin_lock(&fq->q.lock); fq->iif = iif; - ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff); + ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff, + &prob_offset); spin_unlock(&fq->q.lock); inet_frag_put(&fq->q); + if (prob_offset) { + __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev), + IPSTATS_MIB_INHDRERRORS); + icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, prob_offset); + } return ret; } |