lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 25 May 2020 18:19:59 +0800 From: qzhang2 <qiang.zhang@...driver.com> To: Markus Elfring <Markus.Elfring@....de>, Tejun Heo <tj@...nel.org>, Lai Jiangshan <jiangshanlai@...il.com> Cc: linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org Subject: Re: [PATCH v2] workqueue: Fix double kfree for rescuer I see, kfree does nothing with null pointers and direct return. but again kfree is not a good suggestion. On 5/25/20 5:50 PM, Markus Elfring wrote: >> The duplicate memory release should be deleted from the implementation >> of the callback function "rcu_free_wq". > > I tried to help with the selection of a better commit message. > I have taken another look also at the implementation of the function “destroy_workqueue”. > > * The function call “destroy_workqueue” can be performed there in an if branch > after the statement “wq->rescuer = NULL” was executed. > > * This data processing is independent from a possible call of the > function “call_rcu(&wq->rcu, rcu_free_wq)” in another if branch. > Thus it seems that a null pointer is intentionally passed by a data structure > member to this callback function on demand. > The corresponding call of the function “kfree” can tolerate this special case. > > > Now I find that the proposed change can be inappropriate. > > Regards, > Markus >
Powered by blists - more mailing lists