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由 David Vrabel 提交于
In unmask_evtchn(), when the mask bit is cleared after testing for pending and the event becomes pending between the test and clear, then the upcall will not become pending and the event may be lost or delayed. Avoid this by always clearing the mask bit before checking for pending. If a hypercall is needed, remask the event as EVTCHNOP_unmask will only retrigger pending events if they were masked. This fixes a regression introduced in 3.7 by b5e57923 (xen/events: fix unmask_evtchn for PV on HVM guests) which reordered the clear mask and check pending operations. Changes in v2: - set mask before hypercall. Cc: stable@vger.kernel.org Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com> Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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