On Tue, 23 Apr 2002 14:09:21 -0400 (EDT),
Alexander Viro <viro@math.psu.edu> wrote:
>
>
>On Tue, 23 Apr 2002, Keith Owens wrote:
>
>> open /dev/foo
>> request_module(foo)
>> load foo, mark !MOD_USED_ONCE.
>
>Another process:
> open /dev/foo
> MOD_INC_USE_COUNT
> mark MOD_USED_ONCE
> close /dev/foo
> MOD_DEC_USE_COUNT
>rmmod -a
> kills module
>
>> continue with open, MOD_INC_USE_COUNT(foo), mark MOD_USED_ONCE.
> module not loaded
You need two rmmod -a sweeps with no intervening activity on the module
before the module will be autocleaned. See MOD_VISITED. Unless the
first process hangs in the kernel for minutes, it will find the module
still present, use the module and cancel the rmmod -a status.
BTW, I do not disagree that module unloading in general is racy,
especially for ancillary data such as exception tables, unwind data,
timers, kernel threads etc. Which is why Rusty and I plan to rewrite
module loading and unloading in 2.5. I just do not see a race in the
area you are looking at.
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This archive was generated by hypermail 2b29 : Tue Apr 23 2002 - 22:00:37 EST