On Thu, 2018-01-11 at 21:00 +0200, Leon Romanovsky wrote:

On Thu, Jan 11, 2018 at 04:02:33PM +0000, Bart Van Assche wrote:

...

On Thu, 2018-01-11 at 08:22 +0200, Leon Romanovsky wrote:

...

The proposed patch definitely decreases the chance of races, but it is not fixing them. There is a chance to have change in qp state immediately after your "if ..." check.

Hello Leon,

Please have a look at rxe_qp_error() and you will see that the patch I posted is a proper fix. In the scenario you described rxe_qp_error() will trigger a run of rxe_completer().

Bart,

What am I missing?

CPU1 CPU2 if (unlikely.... <--- /* move the qp to the error state */ void rxe_qp_error(struct rxe_qp *qp) { qp->req.state = QP_STATE_ERROR; qp->resp.state = QP_STATE_ERROR; qp->attr.qp_state = IB_QPS_ERR; ---> rxe_run_task(&qp->req.task, must_sched);

It is more or less the same as without "if (unlikely..."

Hello Leon,

In the above the part of rxe_qp_error() that I was referring to in my e-mail is missing:

if (qp_type(qp) == IB_QPT_RC) rxe_run_task(&qp->comp.task, 1);

Bart.