Re: pre-patch-2.1.107 breaks kmod
Adam J. Richter (adam@yggdrasil.com)
Thu, 25 Jun 1998 21:51:24 -0700
In article <6muku5$10u$1@palladium.transmeta.com> H. Peter Anvin writes:
>Followup to: <Pine.LNX.3.95.980625125330.27350M-100000@penguin.transmeta.com>
>By author: Linus Torvalds <torvalds@transmeta.com>
>In newsgroup: linux.dev.kernel
>>
>> On Thu, 25 Jun 1998, Alan Cox wrote:
>> > > The patch does fix a real problem, though. Some kind of re-entrancy block
>> > > is needed to make sure that there aren't two copies of "insmod" trying to
>> > > insert the same module at the same time. It is possible that this
>> >
>> > Why ?
>> >
>> > One of the insmod requests will fail. All that matters is that the
>> > registering in module namespace is atomic, not that we load a
>> > module twice and one bales
>>
>> Have you actually tried it?
>>
>> The problem is that without the lock, it _isn't_ atomic.
>>
>> Linus
>>
>
>Well, that's the bug then -- loading two modules with the name name is
>illegal, and *has* to work such that exactly one succeeds even if it
>happens at the same time.
This would be a bug in the create_module(2) system call, not kmod or
the insmod program.
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