From mboxrd@z Thu Jan 1 00:00:00 1970 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 E8895C4332F for ; Tue, 18 Oct 2022 00:13:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231552AbiJRANd (ORCPT ); Mon, 17 Oct 2022 20:13:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36408 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230175AbiJRAMi (ORCPT ); Mon, 17 Oct 2022 20:12:38 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52C6387FB5; Mon, 17 Oct 2022 17:09:17 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 954E661302; Tue, 18 Oct 2022 00:08:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EDE81C433B5; Tue, 18 Oct 2022 00:08:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666051733; bh=suO48gKpN6vaGn7ollF2e/6WDrLDFaf4THUYc859unw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QqgdIlEgEM/1Q/NVPPtquNcTAiFNkVR91/uFuO9+nIkHWAdmAayxlrKEB2LOUnnxl HkcskpR0nHypMjdIPw5sHaUxGzBUt8Gz9k25Po7MlLsCJEZlfQT1zz2mv11u8yUxRG nihI403tJ7uUl6UfKHTaQ6PtZCGWB99zOwhfqFGDnkNLENyhOYXiNE6kA68mlohUtd Gd7Zz1eF6E9jRWc3Do5lQP2SIqO9jTKrIN6HDTSsh5hXr3AdloEXA9dWLj25vxkGIy UZhEpjg+ZkPyY53+znd3X2JN8nwD8usmw//aCHe2qzYQa2ISpPRwgcAJ3qlgJWs4ad wkwPAFoXP2TyQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Tejun Heo , Abhishek Shah , Gabriel Ryan , Christian Brauner , Sasha Levin , lizefan.x@bytedance.com, hannes@cmpxchg.org, cgroups@vger.kernel.org Subject: [PATCH AUTOSEL 5.19 06/29] cgroup: Remove data-race around cgrp_dfl_visible Date: Mon, 17 Oct 2022 20:08:15 -0400 Message-Id: <20221018000839.2730954-6-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221018000839.2730954-1-sashal@kernel.org> References: <20221018000839.2730954-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tejun Heo [ Upstream commit dc79ec1b232ad2c165d381d3dd2626df4ef9b5a4 ] There's a seemingly harmless data-race around cgrp_dfl_visible detected by kernel concurrency sanitizer. Let's remove it by throwing WRITE/READ_ONCE at it. Signed-off-by: Tejun Heo Reported-by: Abhishek Shah Cc: Gabriel Ryan Reviewed-by: Christian Brauner (Microsoft) Link: https://lore.kernel.org/netdev/20220819072256.fn7ctciefy4fc4cu@wittgenstein/ Signed-off-by: Sasha Levin --- kernel/cgroup/cgroup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 80c23f48f3b4..1969ba9b4090 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -2153,7 +2153,7 @@ static int cgroup_get_tree(struct fs_context *fc) struct cgroup_fs_context *ctx = cgroup_fc2context(fc); int ret; - cgrp_dfl_visible = true; + WRITE_ONCE(cgrp_dfl_visible, true); cgroup_get_live(&cgrp_dfl_root.cgrp); ctx->root = &cgrp_dfl_root; @@ -6068,7 +6068,7 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, struct cgroup *cgrp; int ssid, count = 0; - if (root == &cgrp_dfl_root && !cgrp_dfl_visible) + if (root == &cgrp_dfl_root && !READ_ONCE(cgrp_dfl_visible)) continue; seq_printf(m, "%d:", root->hierarchy_id); -- 2.35.1