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| author |   Eric Dumazet <edumazet@google.com> | 2016-07-08 11:03:57 +0200 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2016-07-09 18:14:17 -0400 |
| commit | 95556a883834122c616bbeb942654d745ceb9712 (patch) | |
| tree | 38d19b84c9d1d2b632f0c08a321dd9fb44c7e5f3 /net | |
| parent | Merge branch 'ibmvnic-fixes' (diff) | |
| download | linux-dev-95556a883834122c616bbeb942654d745ceb9712.tar.xz linux-dev-95556a883834122c616bbeb942654d745ceb9712.zip | |
dccp: avoid deadlock in dccp_v4_ctl_send_reset
In the prep work I did before enabling BH while handling socket backlog,
I missed two points in DCCP :
1) dccp_v4_ctl_send_reset() uses bh_lock_sock(), assuming BH were
blocked. It is not anymore always true.
2) dccp_v4_route_skb() was using __IP_INC_STATS() instead of
IP_INC_STATS()
A similar fix was done for TCP, in commit 47dcc20a39d0
("ipv4: tcp: ip_send_unicast_reply() is not BH safe")
Fixes: 7309f8821fd6 ("dccp: do not assume DCCP code is non preemptible")
Fixes: 5413d1babe8f ("net: do not block BH while processing socket backlog")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/dccp/ipv4.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index 5c7e413a3ae4..25dd25b47d41 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -462,7 +462,7 @@ static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk, security_skb_classify_flow(skb, flowi4_to_flowi(&fl4)); rt = ip_route_output_flow(net, &fl4, sk); if (IS_ERR(rt)) { - __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); + IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); return NULL; } @@ -527,17 +527,19 @@ static void dccp_v4_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb) rxiph->daddr); skb_dst_set(skb, dst_clone(dst)); + local_bh_disable(); bh_lock_sock(ctl_sk); err = ip_build_and_send_pkt(skb, ctl_sk, rxiph->daddr, rxiph->saddr, NULL); bh_unlock_sock(ctl_sk); if (net_xmit_eval(err) == 0) { - DCCP_INC_STATS(DCCP_MIB_OUTSEGS); - DCCP_INC_STATS(DCCP_MIB_OUTRSTS); + __DCCP_INC_STATS(DCCP_MIB_OUTSEGS); + __DCCP_INC_STATS(DCCP_MIB_OUTRSTS); } + local_bh_enable(); out: - dst_release(dst); + dst_release(dst); } static void dccp_v4_reqsk_destructor(struct request_sock *req) |