verify: check that the block size is big enough

Fixes: https://github.com/axboe/fio/issues/822
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 4 insertions, 0 deletions

diff --git a/verify.c b/verify.c
index 48ba051d..37d2be8d 100644
--- a/verify.c
+++ b/verify.c
@@ -1191,6 +1191,10 @@ static void populate_hdr(struct thread_data *td, struct io_u *io_u,
 
 	fill_hdr(td, io_u, hdr, header_num, header_len, io_u->rand_seed);
 
+	if (header_len <= hdr_size(td, hdr)) {
+		td_verror(td, EINVAL, "Blocksize too small");
+		return;
+	}
 	data_len = header_len - hdr_size(td, hdr);
 
 	data = p + hdr_size(td, hdr);