When a mutex owner with potential proxies wakes up those proxies are
activated as well, on the same CPU of the owner. They might have been
sleeping on a different CPU however.
Fixup potential proxies CPU at wakeup time before activating them (or
they get woken up with a wrong CPU reference).
Signed-off-by: Juri Lelli <juri.lelli@xxxxxxxxxx>
---
kernel/sched/core.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 54003515fd29..0314afe4ba80 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1664,6 +1664,14 @@ static inline void ttwu_activate(struct rq *rq, struct task_struct *p, int en_fl
blocked_entry);
list_del_init(&pp->blocked_entry);
+ /* XXX can't call set_task_cpu() because we are not holding
+ * neither pp->pi_lock nor task's rq lock. This should however
+ * be fine as this task can't be woken up as it is blocked on
+ * this mutex atm.
+ * A problem however might be that __set_task_cpu() calls
+ * set_task_rq() which deals with groups and such...
+ */
+ __set_task_cpu(pp, cpu_of(rq));
activate_task(rq, pp, en_flags);
pp->on_rq = TASK_ON_RQ_QUEUED;
resched_curr(rq);
@@ -3847,7 +3855,8 @@ static void __sched notrace __schedule(bool preempt)
* whether it wants to wake up a task to maintain
* concurrency.
*/
- if (prev->flags & PF_WQ_WORKER) {
+ if ((prev->flags & PF_WQ_WORKER) &&
+ !task_is_blocked(prev)) {
struct task_struct *to_wakeup;
to_wakeup = wq_worker_sleeping(prev);
--
2.17.1
