Re: [patch] For 2.4: syscall revoke.

From: Alan Cox (alan@lxorguk.ukuu.org.uk)
Date: Fri Oct 13 2000 - 13:26:09 EST


> 1) one process does read() on device, another does revoke()
> followed by rmmod. Oops - nothing holds module in memory, the first
> process is executing code from that module (->read(), that is) and
> we unmap that code.
>
> 2) every access to ->f_op suddenly becomes unsafe. Basically the
> same scenario, but here we have the window between fetching ->f_op and
> calling ->f_op->foo. You have no exclusion here, and even if you had, you
> still got #1 to deal with.

Is #2 actually a problem if #1 is ok. We don't destroy f_ops tables except
on a module unload. Another thing that is arguable is that revoke() should
not return until the revocation is completed. That would solve #1 in the
process I belive ?

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