From 3ba9f93b12361e005dd65fcc8072b42e3189f4f4 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 11 Jun 2021 10:28:13 +0200 Subject: sched,perf,kvm: Fix preemption condition When ran from the sched-out path (preempt_notifier or perf_event), p->state is irrelevant to determine preemption. You can get preempted with !task_is_running() just fine. The right indicator for preemption is if the task is still on the runqueue in the sched-out path. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Mark Rutland Link: https://lore.kernel.org/r/20210611082838.285099381@infradead.org --- kernel/events/core.c | 7 +++---- virt/kvm/kvm_main.c | 2 +- 2 files changed, 4 insertions(+), 5 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index fe88d6eea3c2..fd89000c9bf5 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8682,13 +8682,12 @@ static void perf_event_switch(struct task_struct *task, }, }; - if (!sched_in && task->state == TASK_RUNNING) + if (!sched_in && task->on_rq) { switch_event.event_id.header.misc |= PERF_RECORD_MISC_SWITCH_OUT_PREEMPT; + } - perf_iterate_sb(perf_event_switch_output, - &switch_event, - NULL); + perf_iterate_sb(perf_event_switch_output, &switch_event, NULL); } /* diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 6a6bc7af0e28..5f166eb8ee2e 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -5025,7 +5025,7 @@ static void kvm_sched_out(struct preempt_notifier *pn, { struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn); - if (current->state == TASK_RUNNING) { + if (current->on_rq) { WRITE_ONCE(vcpu->preempted, true); WRITE_ONCE(vcpu->ready, true); } -- cgit v1.2.3