block: fix the bio_vec array index out-of-bounds test

Current bio_vec array index out-of-bounds test within __end_that_request_first() does not seem correct. It checks bio->bi_idx against bio->bi_vcnt, but the subsequent code uses idx (which is, bio->bi_idx + next_idx) as the array index into bio_vec array. This means that the test really make sense only at the first iteration of !(nr_bytes >=bio->bi_size) case (when next_idx == zero). Fix this by replacing bio->bi_idx with idx. (This patch applies to 2.6.30-rc4.) Signed-off-by: Kazuhisa Ichikawa <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
jix · May 12, 2009 · af498d7 · af498d7
1 parent a4d7749
commit af498d7
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/block/blk-core.c b/block/blk-core.c
@@ -1768,10 +1768,10 @@ static int __end_that_request_first(struct request *req, int error,
 		} else {
 			int idx = bio->bi_idx + next_idx;
 
-			if (unlikely(bio->bi_idx >= bio->bi_vcnt)) {
+			if (unlikely(idx >= bio->bi_vcnt)) {
 				blk_dump_rq_flags(req, "__end_that");
 				printk(KERN_ERR "%s: bio idx %d >= vcnt %d\n",
-				       __func__, bio->bi_idx, bio->bi_vcnt);
+				       __func__, idx, bio->bi_vcnt);
 				break;
 			}