mptcp: provide rmem[0] limit

The mptcp proto struct currently does not provide the
required limit for forward memory scheduling. Under
pressure sk_rmem_schedule() will unconditionally try
to use such field and will oops.

Address the issue inheriting the tcp limit, as we already
do for the wmem one.

Fixes: 9c3f94e1681b ("mptcp: add missing memory scheduling in the rx path")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Link: https://lore.kernel.org/r/37af798bd46f402fb7c79f57ebbdd00614f5d7fa.1604861097.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index e7419fd..88f2a7a 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2467,6 +2467,7 @@ static struct proto mptcp_prot = {
        .memory_pressure        = &tcp_memory_pressure,
        .stream_memory_free     = mptcp_memory_free,
        .sysctl_wmem_offset     = offsetof(struct net, ipv4.sysctl_tcp_wmem),
+       .sysctl_rmem_offset     = offsetof(struct net, ipv4.sysctl_tcp_rmem),
        .sysctl_mem     = sysctl_tcp_mem,
        .obj_size       = sizeof(struct mptcp_sock),
        .slab_flags     = SLAB_TYPESAFE_BY_RCU,