Messages in this thread | | | From | David Howells <> | Subject | Re: [PATCH] fix race in mark_mounts_for_expiry() | Date | Wed, 18 May 2005 12:51:39 +0100 |
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Miklos Szeredi <miklos@szeredi.hu> wrote:
> Do you think my original fix is wrong, or is this just cosmetics?
What you're doing is tricky. It's asking for a race. Admittedly, it may not occur in the particular situation you're looking at, but can you always guarantee that? Remember, it may be a race against some piece of code that's not yet written, by an author who doesn't realise what _you_ are doing here because their changeset doesn't intersect with yours.
Remember: you have, in effect, made the usage count on that structure non-atomic.
I do something like that in rwsems and it's something I have to be very careful about. The main reason I can get away with it is that the actual implementation of rwsems is small and is located in a very restrictes set of places and it's not intermingled with other stuff.
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