diff --git a/block/blk-core.c b/block/blk-core.c
index c89883b..9b11aea 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -163,8 +163,18 @@ static void req_bio_endio(struct request *rq, struct bio *bio,
 		if (bio_integrity(bio))
 			bio_integrity_advance(bio, nbytes);
 
-		if (bio->bi_size == 0)
+		if (bio->bi_size == 0) {
+			static unsigned cnt;
+			if (bio_rw_ahead(bio) && !error && !(++cnt % 40)) {
+				printk("XXX %s: failing readahead bio, "
+				       "sec=%llu f=0x%lx rw=0x%lx\n",
+				       rq->rq_disk ? rq->rq_disk->disk_name : "?",
+				       (unsigned long long)bio->bi_sector,
+				       bio->bi_flags, bio->bi_rw);
+				error = -EIO;
+			}
 			bio_endio(bio, error);
+		}
 	} else {
 
 		/*