Re: [PATCH] Describe race of direct read and fork for unaligned buffers

From: Nick Piggin
Date: Tue May 01 2012 - 02:50:04 EST


On 30 April 2012 19:30, Jan Kara <jack@xxxxxxx> wrote:
> This is a long standing problem (or a surprising feature) in our implementation
> of get_user_pages() (used by direct IO). Since several attempts to fix it
> failed (e.g.
> http://linux.derkeiler.com/Mailing-Lists/Kernel/2009-04/msg06542.html, or
> http://lkml.indiana.edu/hypermail/linux/kernel/0903.1/01498.html refused in
> http://comments.gmane.org/gmane.linux.kernel.mm/31569) and it's not completely
> clear whether we really want to fix it given the costs, let's at least document
> it.

In any case, it should be documented even if it is ever fixed in newer
kernels. Thanks!
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