Commit 2585014188d5 ("rcu-tasks: Be more patient for RCU Tasks
boot-time testing") fixes false positive rcu_tasks verification check
failure by repeating the test once every second until timeout using
schedule_timeout_uninterruptible().
Since rcu_tasks_verify_selft_tests() is called from do_initcalls()
as a late_initcall, this has the undesirable side effect of perhaps
delaying other late_initcall's queued after it by a second or more.
Fix this by using delayed_work to repeat the verification check instead.
Fixes: 2585014188d5 ("rcu-tasks: Be more patient for RCU Tasks boot-time testing")
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
---
kernel/rcu/tasks.h | 35 ++++++++++++++++++++++++++++++++---
1 file changed, 32 insertions(+), 3 deletions(-)
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index fcbd0ec33c86..e151cd5ae2bc 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -1832,6 +1832,11 @@ static void rcu_tasks_initiate_self_tests(void)
#endif
}
+/*
+ * Return: 0 - test passed
+ * 1 - test failed, but have not timed out yet
+ * -1 - test failed and timed out
+ */
static int rcu_tasks_verify_self_tests(void)
{
int ret = 0;
@@ -1847,16 +1852,40 @@ static int rcu_tasks_verify_self_tests(void)
ret = -1;
break;
}
- schedule_timeout_uninterruptible(1);
+ ret = 1;
+ break;
}
}
- if (ret)
+ if (ret < 0)
WARN_ON(1);
return ret;
}
-late_initcall(rcu_tasks_verify_self_tests);
+
+/*
+ * Repeat the rcu_tasks_verify_self_tests() call once every second until the
+ * test passes or has timed out.
+ */
+static struct delayed_work rcu_tasks_verify_work;
+static void rcu_tasks_verify_work_fn(struct work_struct *work __maybe_unused)
+{
+ int ret = rcu_tasks_verify_self_tests();
+
+ if (ret <= 0)
+ return;
+
+ /* Test fails but not timed out yet, reschedule another check */
+ schedule_delayed_work(&rcu_tasks_verify_work, HZ);
+}
+
+static int rcu_tasks_verify_schedule_work(void)
+{
+ INIT_DELAYED_WORK(&rcu_tasks_verify_work, rcu_tasks_verify_work_fn);
+ rcu_tasks_verify_work_fn(NULL);
+ return 0;
+}
+late_initcall(rcu_tasks_verify_schedule_work);
#else /* #ifdef CONFIG_PROVE_RCU */
static void rcu_tasks_initiate_self_tests(void) { }
#endif /* #else #ifdef CONFIG_PROVE_RCU */
--
2.31.1
