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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4390CC43215 for ; Tue, 19 Nov 2019 05:21:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 11B432235D for ; Tue, 19 Nov 2019 05:21:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574140886; bh=VuFC/eywt7h/O4gNzTZEFXUuvrmosZ8nF36EuyKYbEg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XOsCugAmKb/UxZ+mdA3Ok5Q4/OY+8YLfKRhUGN63PJEF+P5OzmSrJ+1yjIG/ZzjlM GzViq7b0pzAtJv0T1JkkPwckiuTm+jsUWqqP97G4BZvsX2vwdJYtOQ33yi2nRH/4dI cRf+GyiO0VElQpMPrcFuegIS0GhjurEzifE8XkVs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727363AbfKSFVZ (ORCPT ); Tue, 19 Nov 2019 00:21:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:36254 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727243AbfKSFVX (ORCPT ); Tue, 19 Nov 2019 00:21:23 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 442A52235D; Tue, 19 Nov 2019 05:21:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574140881; bh=VuFC/eywt7h/O4gNzTZEFXUuvrmosZ8nF36EuyKYbEg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AYWvtxXhCaaJZawBt+IkFHsSO/Q5ZO6DciMK+11YJr4fbmXVRaz8bdmR8KcrsoWBt v6mYAS674g5j1UHZoGR92Vtt79r0uBmT9RAaL0+xI+Vpk9eIf/02hD8cC0bbrjxFOS 0rR7DYsmij4cmf3SdilBKEwokQ9hcP410GGGYu1Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oleg Nesterov , Roman Gushchin , Tejun Heo , Bruce Ashfield Subject: [PATCH 5.3 19/48] cgroup: freezer: call cgroup_enter_frozen() with preemption disabled in ptrace_stop() Date: Tue, 19 Nov 2019 06:19:39 +0100 Message-Id: <20191119051003.108253979@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191119050946.745015350@linuxfoundation.org> References: <20191119050946.745015350@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Oleg Nesterov commit 937c6b27c73e02cd4114f95f5c37ba2c29fadba1 upstream. ptrace_stop() does preempt_enable_no_resched() to avoid the preemption, but after that cgroup_enter_frozen() does spin_lock/unlock and this adds another preemption point. Reported-and-tested-by: Bruce Ashfield Fixes: 76f969e8948d ("cgroup: cgroup v2 freezer") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by: Oleg Nesterov Acked-by: Roman Gushchin Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- kernel/signal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2205,8 +2205,8 @@ static void ptrace_stop(int exit_code, i */ preempt_disable(); read_unlock(&tasklist_lock); - preempt_enable_no_resched(); cgroup_enter_frozen(); + preempt_enable_no_resched(); freezable_schedule(); cgroup_leave_frozen(true); } else {