On Mon, 22 Apr 2002 23:35:51 -0400 (EDT),
Alexander Viro <viro@math.psu.edu> wrote:
>On Tue, 23 Apr 2002, Keith Owens wrote:
>> 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.
Where is the race?
open /dev/foo
request_module(foo)
load foo, mark !MOD_USED_ONCE.
continue with open, MOD_INC_USE_COUNT(foo), mark MOD_USED_ONCE.
return to use, module is locked down
User space closes /dev/foo
Release foo resources.
MOD_DEC_USE_COUNT(foo)
return to user space
rmmod -a cleans up. Nothing is using foo, it is removed.
-
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This archive was generated by hypermail 2b29 : Tue Apr 23 2002 - 22:00:35 EST