linux-kernel - [PATCH v6] workqueue: Remove unnecessary kfree() call in rcu_free

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Date:   Thu, 28 May 2020 09:37:36 +0800
From:   <qiang.zhang@...driver.com>
To:     <tj@...nel.org>
CC:     <jiangshanlai@...il.com>, <markus.elfring@....de>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH v6] workqueue: Remove unnecessary kfree() call in rcu_free_wq()

From: Zhang Qiang <qiang.zhang@...driver.com>

The data structure member "wq->rescuer" was reset to a null pointer
in one if branch. It was passed to a call of the function "kfree"
in the callback function "rcu_free_wq" (which was eventually executed).
The function "kfree" does not perform more meaningful data processing
for a passed null pointer (besides immediately returning from such a call).
Thus delete this function call which became unnecessary with the referenced
software update.

Fixes: def98c84b6cd ("workqueue: Fix spurious sanity check failures in destroy_workqueue()")

Co-developed-by: Markus Elfring <Markus.Elfring@....de> 
Signed-off-by: Zhang Qiang <qiang.zhang@...driver.com>
---
 v1->v2->v3->v4->v5->v6:
 Modify weakly submitted information and tag.

 kernel/workqueue.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 891ccad5f271..a2451cdcd503 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3491,7 +3491,6 @@ static void rcu_free_wq(struct rcu_head *rcu)
 	else
 		free_workqueue_attrs(wq->unbound_attrs);

-	kfree(wq->rescuer);
 	kfree(wq);
 }

-- 
2.24.1