bind mounts, chroots, and mismatching kernel with userland

I have a 32-bit debian system, but I recently needed to mmap large
files, so I started using a 64-bit kernel with my 32-bit userland and
installed a 64-bit debian chroot to run inside.  I use bind mounts for
proc, sys, tmp, dev, and home.  It all works fine, but occasionally, the
filesystem gets corrupted (/ and /home are on the same system).  I am
running linux 3.2.21 (3.2.0-3 in debian).

Have I done something I shouldn't do?

I hope this is the right mailing list for this question; I couldn't find
another linux fs user mailing list.

Thanks,
Jayen