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authorJuergen Gross <jgross@suse.com>2021-06-23 15:09:13 +0200
committerJuergen Gross <jgross@suse.com>2021-06-24 12:52:36 +0200
commit3de218ff39b9e3f0d453fe3154f12a174de44b25 (patch)
tree992878585c4a8ec453556fa77989796fe510849d /drivers/xen/events
parent107866a8eb0b664675a260f1ba0655010fac1e08 (diff)
downloadlinux-3de218ff39b9e3f0d453fe3154f12a174de44b25.tar.bz2
xen/events: reset active flag for lateeoi events later
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>
Diffstat (limited to 'drivers/xen/events')
-rw-r--r--drivers/xen/events/events_base.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 7bbfd58958bc..d7e361fb0548 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -642,6 +642,9 @@ 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);
}
@@ -811,6 +814,7 @@ static void xen_evtchn_close(evtchn_port_t port)
BUG();
}
+/* Not called for lateeoi events. */
static void event_handler_exit(struct irq_info *info)
{
smp_store_release(&info->is_active, 0);
@@ -1883,7 +1887,12 @@ static void lateeoi_ack_dynirq(struct irq_data *data)
if (VALID_EVTCHN(evtchn)) {
do_mask(info, EVT_MASK_REASON_EOI_PENDING);
- event_handler_exit(info);
+ /*
+ * Don't call event_handler_exit().
+ * Need to keep is_active non-zero in order to ignore re-raised
+ * events after cpu affinity changes while a lateeoi is pending.
+ */
+ clear_evtchn(evtchn);
}
}