Re: [PATCH] add lock hook to prevent race

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chrisat_private

* Antony Edwards (aedwardat_private) wrote:
> Hi,
> 
> This is a patch for consideration. It addresses a race condition detected
> using the validation tools we (IBM) are working on, and also an
> inconsistency in the use of the file_ops->lock hook. It is against the
> 2.5.2 patch. Sorry for the length of the description -- but that's race
> conditions for you.

Anthony, thanks for the detailed report.  This looks like a good catch.
I do like making flock() and fcntl() locks funnel through the same hook.
I realize that copy_from_user can sleep in the fucntions fcntl_[gs]etlk(64),
but it's not clear to me what could be raceable if that (kernel) interface
was changed to using the already looked up filp instead of the fd.

any ideas?

thanks,
-chris
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