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McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Josh Triplett , Boqun Feng , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Uladzislau Rezki , joel@joelfernandes.org, rcu@vger.kernel.org References: <20260103002343.6599-1-joelagnelf@nvidia.com> <20260103002343.6599-2-joelagnelf@nvidia.com> <20260105103145.5b3eaaf5@gandalf.local.home> Content-Language: en-US From: Joel Fernandes In-Reply-To: <20260105103145.5b3eaaf5@gandalf.local.home> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MN2PR18CA0028.namprd18.prod.outlook.com (2603:10b6:208:23c::33) To SN7PR12MB8059.namprd12.prod.outlook.com (2603:10b6:806:32b::7) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SN7PR12MB8059:EE_|IA1PR12MB8286:EE_ X-MS-Office365-Filtering-Correlation-Id: ad1e3d65-a9fe-46c4-0b9f-08de4c714a5a X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|1800799024|366016; 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If this >> warning ever fires, it indicates a bug where a task was added to >> a blocked list without properly setting the blocked flag first. >> >> Signed-off-by: Joel Fernandes >> --- >> kernel/rcu/tree_plugin.h | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h >> index dbe2d02be824..73ba5f4a968d 100644 >> --- a/kernel/rcu/tree_plugin.h >> +++ b/kernel/rcu/tree_plugin.h >> @@ -846,6 +846,7 @@ void exit_rcu(void) >> if (unlikely(!list_empty(¤t->rcu_node_entry))) { >> rcu_preempt_depth_set(1); >> barrier(); >> + WARN_ON_ONCE(!t->rcu_read_unlock_special.b.blocked); >> WRITE_ONCE(t->rcu_read_unlock_special.b.blocked, true); Right, so it is ever not set then we are trying to "right" a "wrong", so.. > > If we warn when it is not set, could we just remove setting it? > Or do: > > if (WARN_ON_ONCE(!t->rcu_read_unlock_special.b.blocked)) > WRITE_ONCE(t->rcu_read_unlock_special.b.blocked, true); .. we could just do this. I'll apply the suggestion, thanks! - Joel