From nobody Tue Jun 23 12:19:24 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B7429C433FE for ; Sat, 5 Mar 2022 03:41:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231129AbiCEDmN (ORCPT ); Fri, 4 Mar 2022 22:42:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51852 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231126AbiCEDmL (ORCPT ); Fri, 4 Mar 2022 22:42:11 -0500 Received: from mail-pj1-x102d.google.com (mail-pj1-x102d.google.com [IPv6:2607:f8b0:4864:20::102d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 82A6C229C98 for ; Fri, 4 Mar 2022 19:41:18 -0800 (PST) Received: by mail-pj1-x102d.google.com with SMTP id mv5-20020a17090b198500b001bf2a039831so2795552pjb.5 for ; Fri, 04 Mar 2022 19:41:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=g3T8Wrd1J7uGYe15NcawUAYKxW858bm+7idoDqUxKYI=; b=MyaYOjbzKClchfYsPyWtaapwj4xAq3tSb4HBkNNsRnhNYZTuEomnmeMB4qHMTVEYLf u7IYfAxFrljMrpJ5U148gK8VLJL8mZSazH5MslieGV4nb3kyeUTiGa7Le9jFztpUzjPK /hFELLvBajcg0wrFpUDLEEcuWt67POL2MCKy4HISQ5W20yghK4E1lQto1s/O6WhNLUml x2J/ZSdWA4XoA655TSnAWldBccQGT4aQZt8nvqrNXarkACbhsq73irzwEX68lHfzexAs UfWnSYy8uEi56AwIIHiEHgvVM2lzs7CBRtb0eAmi3EwVdwpMJSA6Xu5kZ53n6czbV3An tJ3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=g3T8Wrd1J7uGYe15NcawUAYKxW858bm+7idoDqUxKYI=; b=SU3L0EzkDuwcZne5Qx5wzwMKDNWlKP0/ZGI75zXfetz1A7Ao9HRsx+m8Ct1PYTEJyi mg7n5JHq2gFGyl9GVCdmwJP3Xm1xjnRfH0UaD9DTVXo+3oidXKcvGK5G5Pc/bgTkh112 kik54MvJVamjNsEqtof2kLP8gsR8+vY6Llskda6Uz1RZvS7dKRCr1GCxHfNNVAO7Xq49 rzGex5JsHd37hDqlFPzfEYGIq8m59SyITQ4WxJDroITaDcP0vob3+hgNNkRHhRC6eqgH OrQHlcaktghnuUTFZ4QjBmcVMExdT5+5eJutPY/1yhu9gegl4RVf7IKVMY3cVlRsJWKF 5dcg== X-Gm-Message-State: AOAM531n1QiEH4hUrYpPamXA/awWmyvBt4H17SgtV84Xc7SbHrN+Qtvz G+4E+vmlDrFDKMBm6Y9FFA3pDw== X-Google-Smtp-Source: ABdhPJxvVO84UijMWteTh39H+Sz9+e3LBMyDKw84DqwLeJMQyNDa3ooXBiIpls9IiNWRP8tv+hlaIg== X-Received: by 2002:a17:903:124a:b0:151:99fe:1a10 with SMTP id u10-20020a170903124a00b0015199fe1a10mr1545897plh.87.1646451678079; Fri, 04 Mar 2022 19:41:18 -0800 (PST) Received: from localhost.localdomain ([2409:8a28:e6d:cc00:d089:89fd:5c33:f12]) by smtp.gmail.com with ESMTPSA id h5-20020a056a001a4500b004e177b8cbfdsm7360927pfv.197.2022.03.04.19.41.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Mar 2022 19:41:17 -0800 (PST) From: Chengming Zhou To: 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, Chengming Zhou , Linux Kernel Functional Testing , syzbot+16e3f2c77e7c5a0113f9@syzkaller.appspotmail.com, Zhouyi Zhou Subject: [PATCH linux-next] cgroup: fix suspicious rcu_dereference_check() usage warning Date: Sat, 5 Mar 2022 11:41:03 +0800 Message-Id: <20220305034103.57123-1-zhouchengming@bytedance.com> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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 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)) --=20 2.20.1