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From: Andrew Fish <afish@apple.com>
To: Arka Sharma <arka.sw1988@gmail.com>
Cc: edk2-devel@lists.01.org
Subject: Re: Closing events and releasing resources in notify function
Date: Thu, 23 Mar 2017 23:37:46 -0700	[thread overview]
Message-ID: <9C33D691-C2DF-4F19-933D-5D344B96554B@apple.com> (raw)
In-Reply-To: <CAPO=kN0VmZcnqSDQfsEc8AKDazQ+QZNZ+PzNcTTXkrzJfrLJXw@mail.gmail.com>


> On Mar 23, 2017, at 11:22 PM, Arka Sharma <arka.sw1988@gmail.com> wrote:
> 
> Hi,
> 
> Is it ok to close the event and release the resource allocated to be
> sent as context inside the notify function. May be something like this
> 
> VOID
> EFIAPI
> NotifyRoutine (
>       EFI_EVENT Event,
>       VOID  *Context
> )
> {
>   //
>   // Perform intended task
>   //
>   FreePool (Context);
>   gBS->CloseEvent (Event);

You should close the event before you free the context, or you will have a race. You need to make sure there is no way for EFI to signal the event before you free the context. 

This all assumes you don't have other code doing crazy stuff with the Context or Event. It would  be a different answer for CreateEventEx()

Thanks,

Andrew Fish

> }
> 
> In the above example Context was allocated before creating the event
> and passed as a parameter to CreateEvent().
> 
> Regards,
> Arka
> _______________________________________________
> edk2-devel mailing list
> edk2-devel@lists.01.org
> https://lists.01.org/mailman/listinfo/edk2-devel



  reply	other threads:[~2017-03-24  6:37 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-24  6:22 Closing events and releasing resources in notify function Arka Sharma
2017-03-24  6:37 ` Andrew Fish [this message]
2017-03-24  7:07   ` Arka Sharma
2017-03-24  7:08     ` Andrew Fish

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