Commit 47879175 authored Jun 23, 2021 by Juergen Gross Committed by Greg Kroah-Hartman Jul 11, 2021

xen/events: reset active flag for lateeoi events later



commit 3de218ff39b9e3f0d453fe3154f12a174de44b25 upstream.

In order to avoid a race condition for user events when changing
cpu affinity reset the active flag only when EOI-ing the event.

This is working fine as all user events are lateeoi events. Note that
lateeoi_ack_mask_dynirq() is not modified as there is no explicit call
to xen_irq_lateeoi() expected later.

Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Fixes: b6622798bc50b62 ("xen/events: avoid handling the same event on two cpus at the same time")
Tested-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrvsky@oracle.com>
Link: https://lore.kernel.org/r/20210623130913.9405-1-jgross@suse.com


Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent a5c196ba

drivers/xen/events/events_base.c

+19 −4

Original line number	Diff line number	Diff line
		@@ -533,6 +533,9 @@ static void xen_irq_lateeoi_locked(struct irq_info *info, bool spurious)
		}

		info->eoi_time = 0;

		/* is_active hasn't been reset yet, do it now. */
		smp_store_release(&info->is_active, 0);
		do_unmask(info, EVT_MASK_REASON_EOI_PENDING);
		}

		@@ -1777,10 +1780,22 @@ static void lateeoi_ack_dynirq(struct irq_data *data)
		struct irq_info *info = info_for_irq(data->irq);
		evtchn_port_t evtchn = info ? info->evtchn : 0;

		if (VALID_EVTCHN(evtchn)) {
		if (!VALID_EVTCHN(evtchn))
		return;

		do_mask(info, EVT_MASK_REASON_EOI_PENDING);
		ack_dynirq(data);
		}

		if (unlikely(irqd_is_setaffinity_pending(data)) &&
		likely(!irqd_irq_disabled(data))) {
		do_mask(info, EVT_MASK_REASON_TEMPORARY);

		clear_evtchn(evtchn);

		irq_move_masked_irq(data);

		do_unmask(info, EVT_MASK_REASON_TEMPORARY);
		} else
		clear_evtchn(evtchn);
		}

		static void lateeoi_mask_ack_dynirq(struct irq_data *data)