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From: "Paul E. McKenney" <paulmck@kernel.org>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
	rostedt@goodmis.org, Zqiang <qiang1.zhang@intel.com>,
	"Paul E . McKenney" <paulmck@kernel.org>
Subject: [PATCH rcu 1/3] rcu-tasks: Convert RCU_LOCKDEP_WARN() to WARN_ONCE()
Date: Wed, 31 Aug 2022 11:15:54 -0700	[thread overview]
Message-ID: <20220831181556.2696404-1-paulmck@kernel.org> (raw)
In-Reply-To: <20220831181553.GA2696186@paulmck-ThinkPad-P17-Gen-1>

From: Zqiang <qiang1.zhang@intel.com>

Kernels built with CONFIG_PROVE_RCU=y and CONFIG_DEBUG_LOCK_ALLOC=y
attempt to emit a warning when the synchronize_rcu_tasks_generic()
function is called during early boot while the rcu_scheduler_active
variable is RCU_SCHEDULER_INACTIVE.  However the warnings is not
actually be printed because the debug_lockdep_rcu_enabled() returns
false, exactly because the rcu_scheduler_active variable is still equal
to RCU_SCHEDULER_INACTIVE.

This commit therefore replaces RCU_LOCKDEP_WARN() with WARN_ONCE()
to force these warnings to actually be printed.

Signed-off-by: Zqiang <qiang1.zhang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/tasks.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 83c7e6620d403..469bf2a3b505e 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -560,7 +560,7 @@ static int __noreturn rcu_tasks_kthread(void *arg)
 static void synchronize_rcu_tasks_generic(struct rcu_tasks *rtp)
 {
 	/* Complain if the scheduler has not started.  */
-	RCU_LOCKDEP_WARN(rcu_scheduler_active == RCU_SCHEDULER_INACTIVE,
+	WARN_ONCE(rcu_scheduler_active == RCU_SCHEDULER_INACTIVE,
 			 "synchronize_rcu_tasks called too soon");
 
 	// If the grace-period kthread is running, use it.
-- 
2.31.1.189.g2e36527f23


  reply	other threads:[~2022-08-31 18:30 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-31 18:15 [PATCH rcu 0/7] RCU Tasks updates for v6.1 Paul E. McKenney
2022-08-31 18:15 ` Paul E. McKenney [this message]
2022-08-31 18:15 ` [PATCH rcu 2/3] rcu-tasks: Ensure RCU Tasks Trace loops have quiescent states Paul E. McKenney
2022-08-31 18:15 ` [PATCH rcu 3/3] rcu-tasks: Make RCU Tasks Trace check for userspace execution Paul E. McKenney

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