6.1-stable review patch. If anyone has any objections, please let me know.
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From: Costa Shulyupin costa.shul@redhat.com
[ 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@redhat.com Signed-off-by: Costa Shulyupin costa.shul@redhat.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Reviewed-by: Waiman Long longman@redhat.com Link: https://lore.kernel.org/r/20240222200856.569036-1-costa.shul@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/time/hrtimer.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 9bb88836c42e6..314fb7598a879 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> @@ -2220,8 +2221,8 @@ 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);