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Date: Tue, 31 Mar 2026 19:26:33 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Weiming Shi <bestswngs@gmail.com>
Cc: Allison Henderson <allison.henderson@oracle.com>, "David S . Miller"
 <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, Paolo Abeni
 <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
 netdev@vger.kernel.org, linux-rdma@vger.kernel.org, Xiang Mei
 <xmei5@asu.edu>
Subject: Re: [PATCH net] rds: ib: reject FRMR registration before IB
 connection is established
Message-ID: <20260331192633.26144848@kernel.org>
In-Reply-To: <20260330163237.2752440-2-bestswngs@gmail.com>
References: <20260330163237.2752440-2-bestswngs@gmail.com>
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On Tue, 31 Mar 2026 00:32:38 +0800 Weiming Shi wrote:
> rds_ib_get_mr() extracts the rds_ib_connection from conn->c_transport_data
> and passes it to rds_ib_reg_frmr() for FRWR memory registration. On a
> fresh outgoing connection, ic is allocated in rds_ib_conn_alloc() with
> i_cm_id = NULL because the connection worker has not yet called
> rds_ib_conn_path_connect() to create the rdma_cm_id. When sendmsg() with
> RDS_CMSG_RDMA_MAP is called on such a connection, the sendmsg path parses
> the control message before any connection establishment, allowing
> rds_ib_post_reg_frmr() to dereference ic->i_cm_id->qp and crash the
> kernel.

Allison?