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authorEric Dumazet <edumazet@google.com>2016-07-08 11:03:57 +0200
committerDavid S. Miller <davem@davemloft.net>2016-07-09 18:14:17 -0400
commit95556a883834122c616bbeb942654d745ceb9712 (patch)
tree38d19b84c9d1d2b632f0c08a321dd9fb44c7e5f3 /net
parent03addc2bcebd953e74c52f0664629032fd9767e9 (diff)
downloadlinux-95556a883834122c616bbeb942654d745ceb9712.tar.bz2
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.c10
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)