On 8/29/2017 1:34 PM, Roland Dreier wrote:
> From: Roland Dreier <roland@xxxxxxxxxxxxxxx>
>
> A couple of places in the CM do
>
> spin_lock_irq(&cm_id_priv->lock);
> ...
> if (cm_alloc_response_msg(work->port, work->mad_recv_wc, &msg))
>
> However when the underlying transport is RoCE, this leads to a sleeping function
> being called with the lock held - the callchain is
>
> cm_alloc_response_msg() ->
> ib_create_ah_from_wc() ->
> ib_init_ah_from_wc() ->
> rdma_addr_find_l2_eth_by_grh() ->
> rdma_resolve_ip()
>
> and rdma_resolve_ip() starts out by doing
>
> req = kzalloc(sizeof *req, GFP_KERNEL);
>
> not to mention rdma_addr_find_l2_eth_by_grh() doing
>
> wait_for_completion(&ctx.comp);
>
> to wait for the task that rdma_resolve_ip() queues up.
>
> Fix this by moving the AH creation out of the lock.
>
> Signed-off-by: Roland Dreier <roland@xxxxxxxxxxxxxxx>
This looks good Roland, thanks for that. Will apply today.
--
Doug Ledford <dledford@xxxxxxxxxx>
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