[PATCH] block: fix EOD return for device with nr_sectors == 0

[Jens Axboe <axboe@kernel.dk>]

A recent commit skipped dumping the usual "attempt to access beyond end
of device" message if the device size is 0 sectors, as that's a common
pattern for devices that have been hot removed. But while it stopped
that message, it also prevented returning -EIO for that condition.
Reinstate the -EIO return, while retaining the quiet operation for
triggering EOD for a device with 0 sectors.

Reported-by: syzbot+4b12286339fe4c2700c1@syzkaller.appspotmail.com
Reported-by: Sahil Chandna <chandna.linuxkernel@gmail.com>
Fixes: d0a2b527d8c3 ("block: tone down bio_check_eod")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

---

diff --git a/block/blk-core.c b/block/blk-core.c
index 4201504158a1..a27185cd8ede 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -557,9 +557,11 @@ static inline int bio_check_eod(struct bio *bio)
 	sector_t maxsector = bdev_nr_sectors(bio->bi_bdev);
 	unsigned int nr_sectors = bio_sectors(bio);
 
-	if (nr_sectors && maxsector &&
+	if (nr_sectors &&
 	    (nr_sectors > maxsector ||
 	     bio->bi_iter.bi_sector > maxsector - nr_sectors)) {
+		if (!maxsector)
+			return -EIO;
 		pr_info_ratelimited("%s: attempt to access beyond end of device\n"
 				    "%pg: rw=%d, sector=%llu, nr_sectors = %u limit=%llu\n",
 				    current->comm, bio->bi_bdev, bio->bi_opf,

-- 
Jens Axboe