[PATCH v4 18/23] sched: Fix try_invoke_on_locked_down_task() semantics

Masami Hiramatsu
2020-08-28T12:32:07Z

From: Peter Zijlstra <peterz@infradead.org>

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/sched/core.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 2d95dc3f4644..13b0db2d0be2 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3006,15 +3006,14 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
*/
bool try_invoke_on_locked_down_task(struct task_struct *p, bool (*func)(struct task_struct *t, void *arg), void *arg)
{
- bool ret = false;
struct rq_flags rf;
+ bool ret = false;
struct rq *rq;

- lockdep_assert_irqs_enabled();
- raw_spin_lock_irq(&p->pi_lock);
+ raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
if (p->on_rq) {
rq = __task_rq_lock(p, &rf);
- if (task_rq(p) == rq)
+ if (task_rq(p) == rq && rq->curr != p)
ret = func(p, arg);
rq_unlock(rq, &rf);
} else {
@@ -3028,7 +3027,7 @@ bool try_invoke_on_locked_down_task(struct task_struct *p, bool (*func)(struct t
ret = func(p, arg);
}
}
- raw_spin_unlock_irq(&p->pi_lock);
+ raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags);
return ret;
}