block: fix too broad elevator check in blk_mq_free_request()

We added RQF_ELV to tell whether there's an IO scheduler attached, and
RQF_ELVPRIV tells us whether there's an IO scheduler with private data
attached. Don't check RQF_ELV in blk_mq_free_request(), what we care
about here is just if we have scheduler private data attached.

This fixes a boot crash

Fixes: 2ff0682da6e0 ("block: store elevator state in request")
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Reported-by: syzbot+eb8104072aeab6cc1195@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 9248edd..bbc6139 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -580,7 +580,7 @@ void blk_mq_free_request(struct request *rq)
        struct request_queue *q = rq->q;
        struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
 
-       if (rq->rq_flags & (RQF_ELVPRIV | RQF_ELV)) {
+       if (rq->rq_flags & RQF_ELVPRIV) {
                struct elevator_queue *e = q->elevator;
 
                if (e->type->ops.finish_request)