On Mon, Jun 19, 2017 at 03:32:09PM +0200, Paolo Valente wrote:

quoted

static void bfq_finish_request(struct request *rq)
{
-	struct bfq_queue *bfqq = RQ_BFQQ(rq);
-	struct bfq_data *bfqd = bfqq->bfqd;
+	struct bfq_queue *bfqq;
+	struct bfq_data *bfqd;
+
+	if (!rq->elv.icq)
+		return;
+

If this is a rq dispatched from a bfqq (or even a request still in the
scheduler), then just exiting here will break bfq state seriously.
However, I guess that this case can never occur.

It is a request for which we didn't manage to allocate the ioc.

Previously those wouldn't have REQ_ELVPRIV set and thus we wouldn't
call into the finish method.  Now they do and the finish method needs
to handle those just like the init method.