> -----Original Message-----
> From: Dexuan Cui [mailto:de...@microsoft.com]
> Sent: Wednesday, July 16, 2014 12:01 AM
> To: gre...@linuxfoundation.org; linux-ker...@vger.kernel.org; driverdev-
> de...@linuxdriverproject.org; o...@aepfle.de; a...@canonical.com;
> jasow...@redhat.com
> Cc: KY Srinivasan; Haiyang Zhang
> Subject: [PATCH] Drivers: hv: hv_fcopy: fix a race condition for SMP guest
> 
> We should schedule the 5s "timer work" before starting the data transfer,
> otherwise, the data transfer code may finish so fast on another virtual cpu
> that when the code(fcopy_write()) trying to cancel the 5s "timer work" can
> occasionally fail because the "timer work" may haven't been scheduled yet
> and as a result the fcopy process will be aborted wrongly by
> fcopy_work_func() in 5s.
> 
> Thank Liz Zhang <liz...@microsoft.com> for the initial investigation on the
> bug.
> 
> This addresses https://bugzilla.redhat.com/show_bug.cgi?id=1118123
> 
> Tested-by: Liz Zhang <liz...@microsoft.com>
> Cc: K. Y. Srinivasan <k...@microsoft.com>
> Cc: Haiyang Zhang <haiya...@microsoft.com>
> Cc: sta...@vger.kernel.org
> Signed-off-by: Dexuan Cui <de...@microsoft.com>

Thanks Dexuan.
Signed-off-by: K. Y. Srinivasan <k...@microsoft.com>


K. Y

> ---
>  drivers/hv/hv_fcopy.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c index
> eaaa3d8..23b2ce2 100644
> --- a/drivers/hv/hv_fcopy.c
> +++ b/drivers/hv/hv_fcopy.c
> @@ -246,8 +246,8 @@ void hv_fcopy_onchannelcallback(void *context)
>               /*
>                * Send the information to the user-level daemon.
>                */
> -             fcopy_send_data();
>               schedule_delayed_work(&fcopy_work, 5*HZ);
> +             fcopy_send_data();
>               return;
>       }
>       icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION |
> ICMSGHDRFLAG_RESPONSE;
> --
> 1.9.1

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