Messages in this thread | | | Date | Wed, 9 Apr 2008 12:19:50 -0700 (PDT) | From | Davide Libenzi <> | Subject | Re: [patch] eventfd/kaio integration fix |
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On Wed, 9 Apr 2008, Andrew Morton wrote:
> On Wed, 9 Apr 2008 11:45:47 -0700 (PDT) > Davide Libenzi <davidel@xmailserver.org> wrote: > > > Jeff Roberson discovered a race when using kaio eventfd based > > notifications. This patch fixes the race by moving the notification inside > > the spinlocked section of kaio. > > Missing information. > > What are the consequences of this race, when it occurs?
This was described in the original email. I posted a patch back then (waiting for Jeff test feedback - that never came), but then I forgot about it till now:
http://groups.google.com/group/linux.kernel/browse_thread/thread/e814b54c14198616
> > The operation is safe since eventfd > > spinlock and kaio one are unrelated. > > Yes, it's safe from that perspective. > > However with this patch applied, we will no longer run eventfd_signal() if > kiocbIsCancelled(iocb). Convincing is needed, please?
This was the intended behaviour. No event was actually *ready*, so no need to signal completion of an event.
- Davide
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