New tests that I run cause 100% reproductible kernel crashes.
The problems appears that yaffs_FindObjectByName() can be called with name set to NULL.

The code path come from the two calls yaffs_ChangeObjectName() at the end of
yaffs_UnlinkFile() which set name to NULL and cause a crash when strcmp()
is called in yaffs_FindObjectByName().


For the moment I use the attached patch (beware there is also some traces added)
which test early for NULL name in yaffs_FindObjectByName() and return NULL in this case.
It seems to solve the problem, but it need to be checked.

What I find realy hard to understand is why we didn't find this one sooner
(I run previously a heavy test with lot of file creation and deletion and
everything went good :-().


Luc