JFFS2: cannot execute /bin/bash: Permission denied

[Michael Rothwell <rothwell@holly-springs.nc.us>]

I'm building a JFFS2 filesystem on a 16MB CF card. If I try to run
bin/bash (really ash) from the mounted filesystem, it runs. But it will
not run when booting from the flash card, or chrooting into it:

[root@gromit flash]# chroot /mnt/flash
chroot: cannot execute /bin/bash: Permission denied

I have also tried real bash, just to see.

[root@gromit flash]# ls -al bin/*ash
-rwxr-xr-x    1 root     root        94364 Nov 30 23:47 bin/ash
-rwxr-xr-x    1 root     root       519964 Dec  1 11:17 bin/bash

Permissions seem to be correct. Busybox init complains that it cannot
execute /etc/rc.sysinit (specified in inittab, and exists with correct
permissions, #!/bin/sh at the top, etc.) This happens with sh as a
symlink to busybox, to ash, and to bash.

I get no error messages from JFFS2. On my desktop, I'm using a USB CF
reader, and the flash shows up as /dev/sda. On the device that boots
this card, it's /dev/hda. Same symptoms, "Permission denied"

/dev/mtdblock0 on /mnt/flash type jffs2 (rw)
/dev/sda1 on /mnt/flash/boot type ext2 (rw)

Any ideas?