no crash after setting ESP to 0 in module

[Julien Oster]

Hello,

I already asked this once, but since I got no answer I figured I'll
try it again, maybe this time someone has the time to quickly explain
me that thing.

If I build a kernel module which does something like, say:

MOV ESP, 0

in init_module() then I get an oops, insmod (or whatever process tried
to insert the module) gets killed by the kernel and everything goes on
like that never happened.

My question is now: why? How? I really expect the processor to fail
into a triple fault when doing such a nasty thing, since I am in Ring
0 and there isn't any stack to handle the stack fault exception.

Where's the magic?

Regards,
Julien