From: "Paul E. McKenney" <paulmck@kernel.org>
To: Zqiang <qiang1.zhang@intel.com>
Cc: frederic@kernel.org, quic_neeraju@quicinc.com,
rcu@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] rcu: Check the validity of the boost_kthread_task pointer
Date: Thu, 24 Mar 2022 09:00:01 -0700 [thread overview]
Message-ID: <20220324160001.GW4285@paulmck-ThinkPad-P17-Gen-1> (raw)
In-Reply-To: <20220324111515.1810160-1-qiang1.zhang@intel.com>
On Thu, Mar 24, 2022 at 07:15:15PM +0800, Zqiang wrote:
> The boost kthreads may spawn failed, although the probability of
> creation failure is very low, in consideration of the robustness
> of the code, add boost_kthread_task pointer detection.
>
> Signed-off-by: Zqiang <qiang1.zhang@intel.com>
Good catch! As you say, rare, but definitely worth fixing.
I could not resist a bit of wordsmithing. Could you please check
to see if I messed something up?
Thanx, Paul
------------------------------------------------------------------------
commit ad3c438e248cbc41fe30a41287621c3dbfcdf51c
Author: Zqiang <qiang1.zhang@intel.com>
Date: Thu Mar 24 19:15:15 2022 +0800
rcu: Check for successful spawn of ->boost_kthread_task
For the spawning of the priority-boost kthreads can fail, improbable
though this might seem. This commit therefore refrains from attemoting
to initiate RCU priority boosting when The ->boost_kthread_task pointer
is NULL.
Signed-off-by: Zqiang <qiang1.zhang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 6b9bcd45c7b2..d58f6d6073bf 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1125,7 +1125,8 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
__releases(rnp->lock)
{
raw_lockdep_assert_held_rcu_node(rnp);
- if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) {
+ if (!rnp->boost_kthread_task ||
+ (!rcu_preempt_blocked_readers_cgp(rnp) && !rnp->exp_tasks)) {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return;
}
next prev parent reply other threads:[~2022-03-24 16:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-24 11:15 [PATCH] rcu: Check the validity of the boost_kthread_task pointer Zqiang
2022-03-24 16:00 ` Paul E. McKenney [this message]
2022-03-25 0:00 ` Zhang, Qiang1
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