ipv4: fix possible seqlock deadlock
Eric Dumazet [Thu, 14 Nov 2013 21:37:54 +0000 (13:37 -0800)]
[ Upstream commit c9e9042994d37cbc1ee538c500e9da1bb9d1bcdf ]

ip4_datagram_connect() being called from process context,
it should use IP_INC_STATS() instead of IP_INC_STATS_BH()
otherwise we can deadlock on 32bit arches, or get corruptions of
SNMP counters.

Fixes: 584bdf8cbdf6 ("[IPV4]: Fix "ipOutNoRoutes" counter error for TCP and UDP")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/ipv4/datagram.c

index b28e863..19e3637 100644 (file)
@@ -57,7 +57,7 @@ int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
        if (IS_ERR(rt)) {
                err = PTR_ERR(rt);
                if (err == -ENETUNREACH)
-                       IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
+                       IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
                goto out;
        }