This is a note to let you know that I've just added the patch titled
hrtimer: Select housekeeping CPU during migration
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
hrtimer-select-housekeeping-cpu-during-migration.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit ccba8d41540721ca7b69aeacec59ac5cc32c36a7
Author: Costa Shulyupin <costa.shul@xxxxxxxxxx>
Date: Thu Feb 22 22:08:56 2024 +0200
hrtimer: Select housekeeping CPU during migration
[ Upstream commit 56c2cb10120894be40c40a9bf0ce798da14c50f6 ]
During CPU-down hotplug, hrtimers may migrate to isolated CPUs,
compromising CPU isolation.
Address this issue by masking valid CPUs for hrtimers using
housekeeping_cpumask(HK_TYPE_TIMER).
Suggested-by: Waiman Long <longman@xxxxxxxxxx>
Signed-off-by: Costa Shulyupin <costa.shul@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Waiman Long <longman@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240222200856.569036-1-costa.shul@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index edb0f821dceaa..6057fe2e179b0 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -38,6 +38,7 @@
#include <linux/sched/deadline.h>
#include <linux/sched/nohz.h>
#include <linux/sched/debug.h>
+#include <linux/sched/isolation.h>
#include <linux/timer.h>
#include <linux/freezer.h>
#include <linux/compat.h>
@@ -2223,8 +2224,8 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
int hrtimers_cpu_dying(unsigned int dying_cpu)
{
+ int i, ncpu = cpumask_any_and(cpu_active_mask, housekeeping_cpumask(HK_TYPE_TIMER));
struct hrtimer_cpu_base *old_base, *new_base;
- int i, ncpu = cpumask_first(cpu_active_mask);
tick_cancel_sched_timer(dying_cpu);
