4.4-stable patches

added patches:
	xen-events-reset-active-flag-for-lateeoi-events-later.patch

diff --git a/queue-4.4/series b/queue-4.4/series
index e64b0cf3fb06c0ce90d9f12f0c92a69c711f5312..1f135223a8d0549d06a3fca5a84a64287dd951a1 100644 (file)
--- a/queue-4.4/series
+++ b/queue-4.4/series
@@ -1,2 +1,3 @@
 scsi-sr-return-appropriate-error-code-when-disk-is-e.patch
 drm-nouveau-fix-dma_address-check-for-cpu-gpu-sync.patch
+xen-events-reset-active-flag-for-lateeoi-events-later.patch

diff --git a/queue-4.4/xen-events-reset-active-flag-for-lateeoi-events-later.patch b/queue-4.4/xen-events-reset-active-flag-for-lateeoi-events-later.patch
new file mode 100644 (file)
index 0000000..c315de9
--- /dev/null
+++ b/queue-4.4/xen-events-reset-active-flag-for-lateeoi-events-later.patch
@@ -0,0 +1,69 @@
+From 3de218ff39b9e3f0d453fe3154f12a174de44b25 Mon Sep 17 00:00:00 2001
+From: Juergen Gross <jgross@suse.com>
+Date: Wed, 23 Jun 2021 15:09:13 +0200
+Subject: xen/events: reset active flag for lateeoi events later
+
+From: Juergen Gross <jgross@suse.com>
+
+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>
+
+---
+ drivers/xen/events/events_base.c |   23 +++++++++++++++++++----
+ 1 file changed, 19 insertions(+), 4 deletions(-)
+
+--- a/drivers/xen/events/events_base.c
++++ b/drivers/xen/events/events_base.c
+@@ -533,6 +533,9 @@ static void xen_irq_lateeoi_locked(struc
+       }
+ 
+       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 ir
+       struct irq_info *info = info_for_irq(data->irq);
+       evtchn_port_t evtchn = info ? info->evtchn : 0;
+ 
+-      if (VALID_EVTCHN(evtchn)) {
+-              do_mask(info, EVT_MASK_REASON_EOI_PENDING);
+-              ack_dynirq(data);
+-      }
++      if (!VALID_EVTCHN(evtchn))
++              return;
++
++      do_mask(info, EVT_MASK_REASON_EOI_PENDING);
++
++      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)