From: Mike Marciniszyn Date: Sun, 25 Sep 2016 14:41:46 +0000 (-0700) Subject: IB/hfi1: Fix defered ack race with qp destroy X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=72f53af2651957b0b9d6dead72a393eaf9a2c3be;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git IB/hfi1: Fix defered ack race with qp destroy There is a a bug in defered ack stuff that causes a race with the destroy of a QP. A packet causes a defered ack to be pended by putting the QP into an rcd queue. A return from the driver interrupt processing will process that rcd queue of QPs and attempt to do a direct send of the ack. At this point no locks are held and the above QP could now be put in the reset state in the qp destroy logic. A refcount protects the QP while it is in the rcd queue so it isn't going anywhere yet. If the direct send fails to allocate a pio buffer, hfi1_schedule_send() is called to trigger sending an ack from the send engine. There is no state test in that code path. The refcount is then dropped from the driver.c caller potentially allowing the qp destroy to continue from its refcount wait in parallel with the workqueue scheduling of the qp. Cc: stable@vger.kernel.org Reviewed-by: Dennis Dalessandro Signed-off-by: Mike Marciniszyn Signed-off-by: Dennis Dalessandro Signed-off-by: Doug Ledford --- diff --git a/drivers/infiniband/hw/hfi1/rc.c b/drivers/infiniband/hw/hfi1/rc.c index d32f0c86a623..e9623d0166df 100644 --- a/drivers/infiniband/hw/hfi1/rc.c +++ b/drivers/infiniband/hw/hfi1/rc.c @@ -926,8 +926,10 @@ void hfi1_send_rc_ack(struct hfi1_ctxtdata *rcd, struct rvt_qp *qp, return; queue_ack: - this_cpu_inc(*ibp->rvp.rc_qacks); spin_lock_irqsave(&qp->s_lock, flags); + if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK)) + goto unlock; + this_cpu_inc(*ibp->rvp.rc_qacks); qp->s_flags |= RVT_S_ACK_PENDING | RVT_S_RESP_PENDING; qp->s_nak_state = qp->r_nak_state; qp->s_ack_psn = qp->r_ack_psn; @@ -936,6 +938,7 @@ queue_ack: /* Schedule the send tasklet. */ hfi1_schedule_send(qp); +unlock: spin_unlock_irqrestore(&qp->s_lock, flags); }