diff --git a/include/spdk_internal/bdev.h b/include/spdk_internal/bdev.h
index b95c82949..899c5bffa 100644
--- a/include/spdk_internal/bdev.h
+++ b/include/spdk_internal/bdev.h
@@ -380,7 +380,9 @@ void spdk_bdev_poller_stop(struct spdk_bdev_poller **ppoller);
  * \param bdev_io I/O to allocate buffer for.
  * \param cb callback to be called when the buffer is allocated
  * or the bdev_io has an SGL assigned already.
- * \param len size of the buffer to allocate.
+ * \param len size of the buffer to allocate. In case the bdev_io
+ * doesn't have an SGL assigned this field must be no bigger than
+ * \c SPDK_BDEV_LARGE_BUF_MAX_SIZE.
  */
 void spdk_bdev_io_get_buf(struct spdk_bdev_io *bdev_io, spdk_bdev_io_get_buf_cb cb, uint64_t len);
 
diff --git a/lib/bdev/bdev.c b/lib/bdev/bdev.c
index eec49c7e5..8870ced68 100644
--- a/lib/bdev/bdev.c
+++ b/lib/bdev/bdev.c
@@ -282,6 +282,7 @@ spdk_bdev_io_get_buf(struct spdk_bdev_io *bdev_io, spdk_bdev_io_get_buf_cb cb, u
 		return;
 	}
 
+	assert(len <= SPDK_BDEV_LARGE_BUF_MAX_SIZE);
 	ch = spdk_io_channel_get_ctx(bdev_io->ch->mgmt_channel);
 
 	bdev_io->buf_len = len;