From patchwork Fri Jan 17 15:15:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Michal_Koutn=C3=BD?= X-Patchwork-Id: 11339417 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 62CAB13BD for ; Fri, 17 Jan 2020 15:15:55 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3B6912064C for ; Fri, 17 Jan 2020 15:15:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="nw/9BD9n" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B6912064C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=wIQl0UmYSNZWQaJTV9db6dUlPHnGxtuFiQA4AR+H3Ss=; b=nw/9BD9nB1N/Rt JKMOrU9dUe01XEw8ASzEQ/D1qggG6Zljrc33AuZFjtPWwI1gqnAlgbPrriEAmFcuTmK4pada2aS1z 0SN38zVXVuWSOh+yOImFCVKhx2x883793Tfy4UPsrBpv5emESdplgnoxnoNO1p7oN/JN1gB50RWBO ZDFWIqrALRl4Lp+qBDgfzwF52Puvf3z77Itn3Y4VvNvtu/xfv8oKXPxHuEXLmnUt9xgX0Ck/jZFiV 8vV3UELPPgwFgNYrr9ALu6wZ6zrimQFAASIgS0my9dFPGjwZd1xFn+3HHRpX2JcTN+rGh3JfAYNol GMTtSHtH1sP5+0z6pl/A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1isTLl-00005Z-Eg; Fri, 17 Jan 2020 15:15:53 +0000 Received: from mx2.suse.de ([195.135.220.15]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1isTLf-0008VJ-3U; Fri, 17 Jan 2020 15:15:51 +0000 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id C73C5AF41; Fri, 17 Jan 2020 15:15:45 +0000 (UTC) From: =?utf-8?q?Michal_Koutn=C3=BD?= To: cgroups@vger.kernel.org Subject: [PATCH 2/3] cgroup: Iterate tasks that did not finish do_exit() Date: Fri, 17 Jan 2020 16:15:32 +0100 Message-Id: <20200117151533.12381-3-mkoutny@suse.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200117151533.12381-1-mkoutny@suse.com> References: <20200116043612.52782-1-surenb@google.com> <20200117151533.12381-1-mkoutny@suse.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200117_071547_286293_C489E6AC X-CRM114-Status: GOOD ( 12.81 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [195.135.220.15 listed in list.dnswl.org] 0.0 RCVD_IN_MSPIKE_H3 RBL: Good reputation (+3) [195.135.220.15 listed in wl.mailspike.net] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record 0.0 RCVD_IN_MSPIKE_WL Mailspike good senders X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linger.lee@mediatek.com, tomcherry@google.com, shuah@kernel.org, linux-kernel@vger.kernel.org, matthias.bgg@gmail.com, Li Zefan , linux-mediatek@lists.infradead.org, linux-kselftest@vger.kernel.org, Johannes Weiner , Tejun Heo , alex.shi@linux.alibaba.com, kernel-team@android.com, guro@fb.com, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org PF_EXITING is set earlier than actual removal from css_set when a task is exitting. This can confuse cgroup.procs readers who see no PF_EXITING tasks, however, rmdir is checking against css_set membership so it can transitionally fail with EBUSY. Fix this by listing tasks that weren't unlinked from css_set active lists. It may happen that other users of the task iterator (without CSS_TASK_ITER_PROCS) spot a PF_EXITING task before cgroup_exit(). This is equal to the state before commit c03cd7738a83 ("cgroup: Include dying leaders with live threads in PROCS iterations") but it may be reviewed later. Reported-by: Suren Baghdasaryan Fixes: c03cd7738a83 ("cgroup: Include dying leaders with live threads in PROCS iterations") Signed-off-by: Michal Koutný Tested-by: Suren Baghdasaryan --- kernel/cgroup/cgroup.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index b56283e13491..132d258e7172 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4492,11 +4492,12 @@ static void css_task_iter_advance(struct css_task_iter *it) goto repeat; /* and dying leaders w/o live member threads */ - if (!atomic_read(&task->signal->live)) + if (it->cur_list == CSS_SET_TASKS_DYING && + !atomic_read(&task->signal->live)) goto repeat; } else { /* skip all dying ones */ - if (task->flags & PF_EXITING) + if (it->cur_list == CSS_SET_TASKS_DYING) goto repeat; } }