3.13.11.6 -stable review patch. If anyone has any objections, please let me know.
------------------ From: Eric Dumazet <[email protected]> [ Upstream commit 63c6f81cdde58c41da62a8d8a209592e42a0203e ] Its too easy to add thousand of UDP sockets on a particular bucket, and slow down an innocent multicast receiver. Early demux is supposed to be an optimization, we should avoid spending too much time in it. It is interesting to note __udp4_lib_demux_lookup() only tries to match first socket in the chain. 10 is the threshold we already have in __udp4_lib_lookup() to switch to secondary hash. Fixes: 421b3885bf6d5 ("udp: ipv4: Add udp early demux") Signed-off-by: Eric Dumazet <[email protected]> Reported-by: David Held <[email protected]> Cc: Shawn Bohrer <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Kamal Mostafa <[email protected]> --- net/ipv4/udp.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index a7e4729..98ea36d 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1833,6 +1833,10 @@ static struct sock *__udp4_lib_mcast_demux_lookup(struct net *net, unsigned int count, slot = udp_hashfn(net, hnum, udp_table.mask); struct udp_hslot *hslot = &udp_table.hash[slot]; + /* Do not bother scanning a too big list */ + if (hslot->count > 10) + return NULL; + rcu_read_lock(); begin: count = 0; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
