From ecc74e7acb6d4fd53cd042a391fd38f09de3d84a Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 25 Sep 2023 17:54:13 +0200 Subject: [PATCH] xen/events: fix delayed eoi list handling [ Upstream commit 47d970204054f859f35a2237baa75c2d84fcf436 ] When delaying eoi handling of events, the related elements are queued into the percpu lateeoi list. In case the list isn't empty, the elements should be sorted by the time when eoi handling is to happen. Unfortunately a new element will never be queued at the start of the list, even if it has a handling time lower than all other list elements. Fix that by handling that case the same way as for an empty list. Fixes: e99502f76271 ("xen/events: defer eoi in case of excessive number of events") Reported-by: Jan Beulich Signed-off-by: Juergen Gross Reviewed-by: Oleksandr Tyshchenko Signed-off-by: Juergen Gross Signed-off-by: Sasha Levin --- drivers/xen/events/events_base.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index 52891546e697..24e39984914f 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -551,7 +551,9 @@ static void lateeoi_list_add(struct irq_info *info) spin_lock_irqsave(&eoi->eoi_list_lock, flags); - if (list_empty(&eoi->eoi_list)) { + elem = list_first_entry_or_null(&eoi->eoi_list, struct irq_info, + eoi_list); + if (!elem || info->eoi_time < elem->eoi_time) { list_add(&info->eoi_list, &eoi->eoi_list); mod_delayed_work_on(info->eoi_cpu, system_wq, &eoi->delayed, delay);