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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Paolo Abeni <pabeni@redhat.com>,
        Matthieu Baerts <matthieu.baerts@tessares.net>,
        Jakub Kicinski <kuba@kernel.org>
Subject: [PATCH 5.9 248/255] mptcp: provide rmem[0] limit
Date:   Tue, 17 Nov 2020 14:06:28 +0100
Message-Id: <20201117122151.000605205@linuxfoundation.org>
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From: Paolo Abeni <pabeni@redhat.com>

[ Upstream commit 989ef49bdf100cc772b3a8737089df36b1ab1e30 ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/mptcp/protocol.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2122,6 +2122,7 @@ 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,