Re: [RFC] race in request_module()

[Alexander Viro]

On Tue, 23 Apr 2002, Keith Owens wrote:

> There is no such thing as a failing modprobe.  It either works and the
> module is loaded or modprobe does not work and the module is not
> loaded.  This excludes the case where a module oops during init, but
> that is not what you are worried about.
> 
> When a module is loaded, it is marked !MOD_USED_ONCE.  An explicit
> rmmod will get rid of the module but rmmod -a will not.  rmmod -a will
> not remove a module unless __MOD_INC_USE_COUNT has been issued on the
> module at least once, or the module is loaded to satisfy unresolved
> symbols from another module.

Which is still racy - open()/close() bringing stuff from the same module
during the window in question and there we go.

IOW, echo </dev/foo will merrily set MOD_USED_ONCE.