[PATCH v6] workqueue: Remove unnecessary kfree() call in rcu_free_wq()

[PATCH v6] workqueue: Remove unnecessary kfree() call in rcu_free_wq()

[qiang.zhang]

From: Zhang Qiang <qiang.zhang@windriver.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@web.de> 
Signed-off-by: Zhang Qiang <qiang.zhang@windriver.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

Re: [PATCH v6] workqueue: Remove unnecessary kfree() call in rcu_free_wq()

[Markus Elfring]

> Thus delete this function call which became unnecessary with the referenced
> software update.
…
> Co-developed-by: Markus Elfring <Markus.Elfring@web.de>

I guess that this tag should usually trigger another consequence like the following.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?id=b0c3ba31be3e45a130e13b278cf3b90f69bda6f6#n548

Signed-off-by: Markus Elfring <Markus.Elfring@web.de>


Is there a need to tag also the patch review contribution of Lai Jiangshan?
https://lore.kernel.org/lkml/CAJhGHyC4XcNL8yzWZKZ=73wZJej4JwCaAHGV8qjYn-AqcEAEjQ@mail.gmail.com/
https://lore.kernel.org/patchwork/comment/1442889/
https://lkml.org/lkml/2020/5/26/201


I am unsure if such aspects will matter after Tejun Heo responded with the information
“Applied to wq/for-5.8.” to the previous patch version yesterday.
https://lore.kernel.org/lkml/20200527135214.GI83516@mtj.thefacebook.com/
https://lore.kernel.org/patchwork/comment/1443888/


>  v1->v2->v3->v4->v5->v6:
>  Modify weakly submitted information and tag.

I am curious how our imaginations and preferences will evolve further
also for such wording selections.

Regards,
Markus