Hang when make_request calls submit_bio

I am writing a lock device driver in kernel 2.6.32. We need to create a new bio and call submit_bio in make_request before redirecting the bio from the request queue to lower devices. For this, we have made a function my_sync_io (), which is similar to sync_page_io () from md.

However, our my_sync_io () function never returns. Kernel panic after 120 seconds. We think the function is waiting for something like a lock.

Does anyone know about this?

Thank.