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authorNeeraj Upadhyay <neeraju@codeaurora.org>2019-03-29 16:57:08 +0530
committerPaul E. McKenney <paulmck@linux.ibm.com>2019-05-28 09:02:57 -0700
commit3ae976a7e3e87438b8439a01aeb79d4866b1c444 (patch)
tree3909fa53f6a8ea05abfd45fdbeab0423ab62523f /kernel
parentcd6d17b4a4646d4bf2568f3a4de13a5a13e2ed28 (diff)
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rcu: Correctly unlock root node in rcu_check_gp_start_stall()
On systems whose rcu_node tree has only one node, the rcu_check_gp_start_stall() function's values of rnp and rnp_root will be identical. In this case, it clearly does not make sense to release both rnp->lock and rnp_root->lock, but that is exactly what this function does in the last early exit. This commit therefore unlocks only rnp->lock when rnp and rnp_root are equal. Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org> Reviewed-by: Mukesh Ojha <mojha@codeaurora.org> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/rcu/tree_stall.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index f65a73a97323..065183391f75 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;
}