Hi Qing,

> -----Original Message-----
> From: linux-rdma-ow...@vger.kernel.org [mailto:linux-rdma-
> ow...@vger.kernel.org] On Behalf Of Qing Huang
> Sent: Thursday, November 02, 2017 6:22 PM
> To: linux-r...@vger.kernel.org; linux-kernel@vger.kernel.org
> Cc: dledf...@redhat.com; sean.he...@intel.com; hal.rosenst...@gmail.com;
> ira.we...@intel.com; Mark Bloch <ma...@mellanox.com>; Qing Huang
> <qing.hu...@oracle.com>
> Subject: [PATCH] IB/CM: fix memory corruption by avoiding unnecessary
> memset
> 
> The size of path array could be dynamic. However the fixed number(2) of
> memset could cause memory corruption by writing into wrong memory space.
> 
> Fixes: 9fdca4da4d8c (IB/SA: Split struct sa_path_rec based on IB ands
>       ROCE specific fields)
> 
> Signed-off-by: Qing Huang <qing.hu...@oracle.com>
> ---
>  drivers/infiniband/core/cm.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c index
> 4c4b465..af4f6a0 100644
> --- a/drivers/infiniband/core/cm.c
> +++ b/drivers/infiniband/core/cm.c
> @@ -1856,7 +1856,9 @@ static int cm_req_handler(struct cm_work *work)
>       cm_process_routed_req(req_msg, work->mad_recv_wc->wc);
> 
>       memset(&work->path[0], 0, sizeof(work->path[0]));
> -     memset(&work->path[1], 0, sizeof(work->path[1]));
> +     if (cm_req_has_alt_path(req_msg))
> +             memset(&work->path[1], 0, sizeof(work->path[1]));
> +
>       grh = rdma_ah_read_grh(&cm_id_priv->av.ah_attr);
>       ret = ib_get_cached_gid(work->port->cm_dev->ib_device,
>                               work->port->port_num,
> @@ -3823,8 +3825,8 @@ static void cm_recv_handler(struct ib_mad_agent
> *mad_agent,
> 
>       switch (mad_recv_wc->recv_buf.mad->mad_hdr.attr_id) {
>       case CM_REQ_ATTR_ID:
> -             paths = 1 + (((struct cm_req_msg *) mad_recv_wc-
> >recv_buf.mad)->
> -                                                 alt_local_lid != 0);
> +             paths = 1 + cm_req_has_alt_path(
> +                             (struct cm_req_msg *)mad_recv_wc-
> >recv_buf.mad);
>               event = IB_CM_REQ_RECEIVED;
>               break;
>       case CM_MRA_ATTR_ID:
> --
> 2.9.3
> 
Thanks for the patch. Few weeks back I came across this bug and fix [1] is 
merged now by Doug.
[1] has one additional fix in cm_format_req_event() function as well.

[1] https://patchwork.kernel.org/patch/10015997/

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