From 51b2e3517f75fda93a6852a4a209db52a6d2b11d Mon Sep 17 00:00:00 2001 From: Mike Marciniszyn Date: Sun, 25 Sep 2016 07:41:46 -0700 Subject: IB/hfi1: Fix defered ack race with qp destroy commit 72f53af2651957b0b9d6dead72a393eaf9a2c3be upstream. 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. Reviewed-by: Dennis Dalessandro Signed-off-by: Mike Marciniszyn Signed-off-by: Dennis Dalessandro Signed-off-by: Doug Ledford Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/hw/hfi1/rc.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/hw/hfi1/rc.c b/drivers/infiniband/hw/hfi1/rc.c index 5da190e6011b..bcf76c33726b 100644 --- a/drivers/infiniband/hw/hfi1/rc.c +++ b/drivers/infiniband/hw/hfi1/rc.c @@ -932,8 +932,10 @@ 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; @@ -942,6 +944,7 @@ queue_ack: /* Schedule the send tasklet. */ hfi1_schedule_send(qp); +unlock: spin_unlock_irqrestore(&qp->s_lock, flags); } -- cgit v1.2.3