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rcu-tasks: Use delayed_work to delay rcu_tasks_verify_self_tests()

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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 delaying
other late_initcall's queued after it by a second or more.  Fix this by
instead using delayed_work to repeat the verification check.

Fixes: 2585014188d5 ("rcu-tasks: Be more patient for RCU Tasks boot-time testing")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Waiman Long 2022-06-14 08:06:20 -04:00 committed by Paul E. McKenney
parent 1cf1144e84
commit e72ee5e1a8
1 changed files with 32 additions and 5 deletions
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37
kernel/rcu/tasks.h
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@ -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 +1852,38 @@ static int rcu_tasks_verify_self_tests(void)
ret = -1;
break;
}
schedule_timeout_uninterruptible(1);
ret = 1;
break;
}
}
if (ret)
WARN_ON(1);
WARN_ON(ret < 0);
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 */