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Wed, 9 Mar 2022 07:10:27 +0000 (GMT) Received: from eusmgms1.samsung.com (unknown [182.198.249.179]) by eusmtrp1.samsung.com (KnoxPortal) with ESMTP id 20220309071027eusmtrp12de1cc04d97ba6942d59916713b4cbb8~apNAx7Y0C2066120661eusmtrp1R; Wed, 9 Mar 2022 07:10:27 +0000 (GMT) X-AuditID: cbfec7f5-bf3ff70000002814-d7-622852e4163b Received: from eusmtip1.samsung.com ( [203.254.199.221]) by eusmgms1.samsung.com (EUCPMTA) with SMTP id E6.A7.09522.3E258226; Wed, 9 Mar 2022 07:10:27 +0000 (GMT) Received: from [106.210.134.192] (unknown [106.210.134.192]) by eusmtip1.samsung.com (KnoxPortal) with ESMTPA id 20220309071027eusmtip19d569007785921b281798bea93336883~apM--sSZp2204122041eusmtip1k; Wed, 9 Mar 2022 07:10:26 +0000 (GMT) Message-ID: <1be951c7-442f-eb45-a4fc-41fdb771eef7@samsung.com> Date: Wed, 9 Mar 2022 08:10:26 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Subject: Re: [PATCH linux-next] cgroup: fix suspicious rcu_dereference_check() usage warning Content-Language: en-US To: Chengming Zhou , tj@kernel.org, lizefan.x@bytedance.com, hannes@cmpxchg.org, peterz@infradead.org Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, songmuchun@bytedance.com, Linux Kernel Functional Testing , syzbot+16e3f2c77e7c5a0113f9@syzkaller.appspotmail.com, Zhouyi Zhou From: Marek Szyprowski In-Reply-To: <20220305034103.57123-1-zhouchengming@bytedance.com> Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrPKsWRmVeSWpSXmKPExsWy7djP87pPgjSSDJb2sFrcWD6DxWL1Jl+L y7vmsFmceH2EzeLrAS6L470HmCwO3j/HbHH/Yiejxa/lRxktbjZ+YbSYdKOf1YHb49+JNWwe h9+8Z/bYOesuu8fmFVoem1Z1snncubaHzWPmWzWPz5vkAjiiuGxSUnMyy1KL9O0SuDKunXrB UvCAp2LR78nMDYzXuLoYOTkkBEwkOlrmM3UxcnEICaxglFjRN4EZwvnCKLH4ejs7hPOZUeLl kftMMC37bi1jhEgsZ5TYsHwKlPORUeLz4VUsXYwcHLwCdhILLiWCNLAIqEhMn7SNFcTmFRCU ODnzCQuILSqQJPHgQB87iC0sECdx8e1TMJtZQFzi1hOIm0QEWhglLlxdwwriMAs8Z5T43tEN 1s0mYCjR9baLDcTmFHCUWND9iBGiW15i+9s5YE9ICEznlPgxZTnU3S4Sa59dZIOwhSVeHd/C DmHLSJye3MMC0dDMKPHw3Fp2CKeHUeJy0wxGiCpriTvnfrGB/MYsoCmxfpc+RNhR4tWa6awg YQkBPokbbwUhjuCTmLRtOjNEmFeio00IolpNYtbxdXBrD164xDyBUWkWUsDMQgqAWUjemYWw dwEjyypG8dTS4tz01GLjvNRyveLE3OLSvHS95PzcTYzANHb63/GvOxhXvPqod4iRiYPxEKME B7OSCO/98ypJQrwpiZVVqUX58UWlOanFhxilOViUxHmTMzckCgmkJ5akZqemFqQWwWSZODil Gpj0rpatuJ0dYHPAo1pF7rJwaGZ88e9VWxasPb6oIXiB5T9zf8HVwUuObvDK9vR2fcIToCWh bu13Psa1S0Rlw56/TCe2/OmbyOb0+43Y63N7Vr1zFZ+86q6Jjee1ua1vPk6a8Ota04Fwx8N1 0W/StbS6oucc+Z+XuTsj/cXle5vtr5Ypm7Z3xO2f4dZ32lyxf9OehnLBno9xGl5LOu8Jrj31 12VLu+D/dW+shecyfiu95r7hMCvHoYIN6gFnch6tfPz90bS6TR+FtI90355W+zXesu22wmnr gvKeS5/rilicd/Ieu8Jz9ljqa+fSi6pfz5jtX2sn2/Mjz1Gs6fv2bbru6Tv3L39obV73Yi57 mdFjJZbijERDLeai4kQAq8udptIDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrPIsWRmVeSWpSXmKPExsVy+t/xu7qPgzSSDNb361ncWD6DxWL1Jl+L y7vmsFmceH2EzeLrAS6L470HmCwO3j/HbHH/Yiejxa/lRxktbjZ+YbSYdKOf1YHb49+JNWwe h9+8Z/bYOesuu8fmFVoem1Z1snncubaHzWPmWzWPz5vkAjii9GyK8ktLUhUy8otLbJWiDS2M 9AwtLfSMTCz1DI3NY62MTJX07WxSUnMyy1KL9O0S9DKunXrBUvCAp2LR78nMDYzXuLoYOTkk BEwk9t1axtjFyMUhJLCUUeLv309MEAkZiZPTGlghbGGJP9e62CCK3jNKHHi7m6WLkYODV8BO YsGlRJAaFgEViemTtoHV8woISpyc+YQFxBYVSJJ4uW0jK0i5sECcxIXpPCBhZgFxiVtP5jOB jBQRaGGUmLHoCzOIwyzwnFHi55yZjCBVQgIOEpNunQKz2QQMJbreghzBycEp4CixoPsRI8Qk M4murV1QtrzE9rdzmCcwCs1CcscsJAtnIWmZhaRlASPLKkaR1NLi3PTcYkO94sTc4tK8dL3k /NxNjMCY3Xbs5+YdjPNefdQ7xMjEwXiIUYKDWUmE9/55lSQh3pTEyqrUovz4otKc1OJDjKbA wJjILCWanA9MGnkl8YZmBqaGJmaWBqaWZsZK4ryeBR2JQgLpiSWp2ampBalFMH1MHJxSDUx1 p9Z9ULzKMo9v1vPdLCl8V694BP1ZEVmoxbQlPrpx8uTphn7BDFemzTqg2nc+L1z22T4jueXt 8/5uF251cfBhyvn45vfZuJDtfxinC/ScSW83Toh7H/C74LnSofo9MQlqn+vcw6dxrN1v+9Oa u9Irvfx80DOONx6F++71HTlknC1kqDXlZdCOA2q/nuk7rS7USC0+rFxw2v/6J22/7DDl3C+l 4cFmTkK3d7N+bpslunelS1Gg5kaWa/wfn77zOME/504979yEnZdUbmlxhSWs/BKz6nPcn9rk ZYvOV/3ZdnN1rlpk+uU7OoFqf9qmT7kV4eN1XV3gsuuPC9+Lss/tWPNt/lyFSu2qcP7fiXFK LMUZiYZazEXFiQAdyppPYgMAAA== X-CMS-MailID: 20220309071027eucas1p1f066b42f49e524404d898929b60b344f X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20220309071027eucas1p1f066b42f49e524404d898929b60b344f X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20220309071027eucas1p1f066b42f49e524404d898929b60b344f References: <20220305034103.57123-1-zhouchengming@bytedance.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05.03.2022 04:41, Chengming Zhou wrote: > task_css_set_check() will use rcu_dereference_check() to check for > rcu_read_lock_held() on the read-side, which is not true after commit > dc6e0818bc9a ("sched/cpuacct: Optimize away RCU read lock"). This > commit drop explicit rcu_read_lock(), change to RCU-sched read-side > critical section. So fix the RCU warning by adding check for > rcu_read_lock_sched_held(). > > Fixes: dc6e0818bc9a ("sched/cpuacct: Optimize away RCU read lock") > Reported-by: Linux Kernel Functional Testing > Reported-by: syzbot+16e3f2c77e7c5a0113f9@syzkaller.appspotmail.com > Tested-by: Zhouyi Zhou > Signed-off-by: Chengming Zhou Right, this fixes the issue I've reported here: https://lore.kernel.org/all/f4bc652b-115f-35b5-91db-bad3b30fed9b@samsung.com/ Tested-by: Marek Szyprowski > --- > include/linux/cgroup.h | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h > index 1e356c222756..0d1ada8968d7 100644 > --- a/include/linux/cgroup.h > +++ b/include/linux/cgroup.h > @@ -450,6 +450,7 @@ extern struct mutex cgroup_mutex; > extern spinlock_t css_set_lock; > #define task_css_set_check(task, __c) \ > rcu_dereference_check((task)->cgroups, \ > + rcu_read_lock_sched_held() || \ > lockdep_is_held(&cgroup_mutex) || \ > lockdep_is_held(&css_set_lock) || \ > ((task)->flags & PF_EXITING) || (__c)) Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland