[PATCH] sched/wait: Fix a kthread_park race with wait_woken()

From: Arve Hjønnevåg
Date: Thu Apr 06 2023 - 15:41:08 EST


kthread_park and wait_woken have a similar race that kthread_stop and
wait_woken used to have before it was fixed in
cb6538e740d7543cd989128625cf8cac4b471e0a. Extend that fix to also cover
kthread_park.

Signed-off-by: Arve Hjønnevåg <arve@xxxxxxxxxxx>
---
kernel/sched/wait.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
index 133b74730738..a9cf49da884b 100644
--- a/kernel/sched/wait.c
+++ b/kernel/sched/wait.c
@@ -425,9 +425,9 @@ int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, i
}
EXPORT_SYMBOL(autoremove_wake_function);

-static inline bool is_kthread_should_stop(void)
+static inline bool is_kthread_should_stop_or_park(void)
{
- return (current->flags & PF_KTHREAD) && kthread_should_stop();
+ return (current->flags & PF_KTHREAD) && (kthread_should_stop() || kthread_should_park());
}

/*
@@ -459,7 +459,7 @@ long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout)
* or woken_wake_function() sees our store to current->state.
*/
set_current_state(mode); /* A */
- if (!(wq_entry->flags & WQ_FLAG_WOKEN) && !is_kthread_should_stop())
+ if (!(wq_entry->flags & WQ_FLAG_WOKEN) && !is_kthread_should_stop_or_park())
timeout = schedule_timeout(timeout);
__set_current_state(TASK_RUNNING);

--
2.40.0.577.gac1e443424-goog