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From:   "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>
To:     Dexuan Cui <decui@microsoft.com>,
        "'gregkh@linuxfoundation.org'" <gregkh@linuxfoundation.org>,
        KY Srinivasan <kys@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
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Subject: RE: [PATCH] Drivers: hv: vmbus: Reset the channel callback in
 vmbus_onoffer_rescind()
Thread-Topic: [PATCH] Drivers: hv: vmbus: Reset the channel callback in
 vmbus_onoffer_rescind()
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Date:   Fri, 13 Jul 2018 13:59:53 +0000
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From: Dexuan Cui  Sent: Thursday, July 12, 2018 10:53 PM
>=20
> Before setting channel->rescind in vmbus_rescind_cleanup(), we should mak=
e
> sure the channel callback won't run any more, otherwise a high-level
> driver like pci_hyperv, which may be infinitely waiting for the host VSP'=
s
> response and notices the channel has been rescinded, can't safely give
> up: e.g., in hv_pci_protocol_negotiation() -> wait_for_response(), it's
> unsafe to exit from wait_for_response() and proceed with the on-stack
> variable "comp_pkt" popped. The issue was originally spotted by
> Michael Kelley <mikelley@microsoft.com>.
>=20
> In vmbus_close_internal(), the patch also minimizes the range protected b=
y
> disabling/enabling channel->callback_event: we don't really need that for
> the whole function.
>=20
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> Cc: stable@vger.kernel.org
> Cc: K. Y. Srinivasan <kys@microsoft.com>
> Cc: Stephen Hemminger <sthemmin@microsoft.com>
> Cc: Michael Kelley <mikelley@microsoft.com>

Reviewed-by: Michael Kelley <mikelley@microsoft.com>