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Fri, 20 May 2022 09:56:51 -0700 (PDT) Message-ID: <1fadd74c-25d0-b9ab-8a06-27a9faa6579b@linaro.org> Date: Fri, 20 May 2022 09:56:50 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH] cgroup: don't queue css_release_work if one already pending Content-Language: en-US To: =?UTF-8?Q?Michal_Koutn=c3=bd?= Cc: Tejun Heo , Hillf Danton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzbot+e42ae441c3b10acf9e9d@syzkaller.appspotmail.com References: <20220412192459.227740-1-tadeusz.struk@linaro.org> <20220414164409.GA5404@blackbody.suse.cz> <20220422100400.GA29552@blackbody.suse.cz> <20220519112319.2455-1-hdanton@sina.com> <25fb057a-077f-b601-dcb7-130071c733db@linaro.org> <489592f6-b783-7bdb-2cc8-0c8e35ebc674@linaro.org> <20220520164255.GB17335@blackbody.suse.cz> From: Tadeusz Struk In-Reply-To: <20220520164255.GB17335@blackbody.suse.cz> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 8C41F180019 X-Stat-Signature: oxzwppopqbfb1ft1haqze4cgwro8wuoi X-Rspam-User: Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=linaro.org header.s=google header.b="WCgjyI/p"; spf=pass (imf06.hostedemail.com: domain of tadeusz.struk@linaro.org designates 209.85.210.182 as permitted sender) smtp.mailfrom=tadeusz.struk@linaro.org; dmarc=pass (policy=none) header.from=linaro.org X-HE-Tag: 1653065809-964382 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 5/20/22 09:42, Michal Koutný wrote: > On Fri, May 20, 2022 at 09:38:12AM -0700, Tadeusz Struk wrote: >> as this is a result of enqueuing the same css->destroy_work onto the same WQ, >> one on the rcu path and one on the css_release path. >> I will prototype it today and test with syzbot. > In my understanding, you'd need two independent work_structs in a css, > not two separate workqueues to put the single entry on. I think either way would work, but two workqueues would be less churn. I can try both. -- Thanks, Tadeusz