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From:   Neeraj Upadhyay <neeraju@codeaurora.org>
To:     paulmck@linux.vnet.ibm.com, josh@joshtriplett.org,
        rostedt@goodmis.org, mathieu.desnoyers@efficios.com,
        jiangshanlai@gmail.com, joel@joelfernandes.org
Cc:     rcu@vger.kernel.org, linux-kernel@vger.kernel.org,
        Neeraj Upadhyay <neeraju@codeaurora.org>
Subject: [PATCH] rcu: tree_stall: Correctly unlock root node in rcu_check_gp_start_stall
Date:   Fri, 29 Mar 2019 16:57:08 +0530
Message-Id: <1553858828-23097-1-git-send-email-neeraju@codeaurora.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Only unlock the root node, if current node (rnp) is not
root node.

Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
---
 kernel/rcu/tree_stall.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index f65a73a..0651833 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -630,7 +630,9 @@ static void rcu_check_gp_start_stall(struct rcu_node *rnp, struct rcu_data *rdp,
 	    time_before(j, rcu_state.gp_req_activity + gpssdelay) ||
 	    time_before(j, rcu_state.gp_activity + gpssdelay) ||
 	    atomic_xchg(&warned, 1)) {
-		raw_spin_unlock_rcu_node(rnp_root); /* irqs remain disabled. */
+		if (rnp_root != rnp)
+			/* irqs remain disabled. */
+			raw_spin_unlock_rcu_node(rnp_root);
 		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
 		return;
 	}
-- 
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