On Sun, 16 Jan 2000, David Woodhouse wrote:
>
> tigran@sco.COM said:
> > see, the above does the second check only if the module successfully
> > loaded because there is no way for some feature to be added to the
> > kernel otherwise.
>
> What if another CPU loads the module between the first check and the
> request_module()? Then request_module() will fail because the module's already
> loaded, won't it?
which is why (amongst other reasons) you will notice lock/unlock_kernel()
in sys_open() around call to filp_open(). (I just grabbed misc_open() as a
random example of calling request_module() and was satisfied that the code
is safe)
A good exercise would be to go through all calls and see if each case
provides such mutex against itself. Have you done that? :)
Regards,
Tigran.
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