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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 D6CF6C433FE for ; Mon, 13 Sep 2021 13:19:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BBD0961209 for ; Mon, 13 Sep 2021 13:19:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240276AbhIMNUw (ORCPT ); Mon, 13 Sep 2021 09:20:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:34856 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239450AbhIMNTu (ORCPT ); Mon, 13 Sep 2021 09:19:50 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id BE530610CE; Mon, 13 Sep 2021 13:17:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631539049; bh=uUIWVZz5XUg/rEj4UYTgGO8eQs3sAcwNHViLVpRV0QA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tEvHID81TH4elvWsxCui7YKewn+9ZN5cD1VVLd5Is73dz2LiHB3alVsrcRGTDSUlC JTgHat1Bj7Dgl4NBxgEjGuoWA49DBJ8FKDpeztjatvfs/YmKrGgDUrPwlybtN3t64K OU/dNJERu/9YoMvLT4NHHwbpiwANTgOy9XPLKby8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Quentin Perret , "Peter Zijlstra (Intel)" , Sasha Levin Subject: [PATCH 5.4 004/144] sched/deadline: Fix reset_on_fork reporting of DL tasks Date: Mon, 13 Sep 2021 15:13:05 +0200 Message-Id: <20210913131048.118188162@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210913131047.974309396@linuxfoundation.org> References: <20210913131047.974309396@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Quentin Perret [ Upstream commit f95091536f78971b269ec321b057b8d630b0ad8a ] It is possible for sched_getattr() to incorrectly report the state of the reset_on_fork flag when called on a deadline task. Indeed, if the flag was set on a deadline task using sched_setattr() with flags (SCHED_FLAG_RESET_ON_FORK | SCHED_FLAG_KEEP_PARAMS), then p->sched_reset_on_fork will be set, but __setscheduler() will bail out early, which means that the dl_se->flags will not get updated by __setscheduler_params()->__setparam_dl(). Consequently, if sched_getattr() is then called on the task, __getparam_dl() will override kattr.sched_flags with the now out-of-date copy in dl_se->flags and report the stale value to userspace. To fix this, make sure to only copy the flags that are relevant to sched_deadline to and from the dl_se->flags field. Signed-off-by: Quentin Perret Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210727101103.2729607-2-qperret@google.com Signed-off-by: Sasha Levin --- kernel/sched/deadline.c | 7 ++++--- kernel/sched/sched.h | 2 ++ 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 3cf776d5bce8..7ab0b80cb12d 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2622,7 +2622,7 @@ void __setparam_dl(struct task_struct *p, const struct sched_attr *attr) dl_se->dl_runtime = attr->sched_runtime; dl_se->dl_deadline = attr->sched_deadline; dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; - dl_se->flags = attr->sched_flags; + dl_se->flags = attr->sched_flags & SCHED_DL_FLAGS; dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); dl_se->dl_density = to_ratio(dl_se->dl_deadline, dl_se->dl_runtime); } @@ -2635,7 +2635,8 @@ void __getparam_dl(struct task_struct *p, struct sched_attr *attr) attr->sched_runtime = dl_se->dl_runtime; attr->sched_deadline = dl_se->dl_deadline; attr->sched_period = dl_se->dl_period; - attr->sched_flags = dl_se->flags; + attr->sched_flags &= ~SCHED_DL_FLAGS; + attr->sched_flags |= dl_se->flags; } /* @@ -2710,7 +2711,7 @@ bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr) if (dl_se->dl_runtime != attr->sched_runtime || dl_se->dl_deadline != attr->sched_deadline || dl_se->dl_period != attr->sched_period || - dl_se->flags != attr->sched_flags) + dl_se->flags != (attr->sched_flags & SCHED_DL_FLAGS)) return true; return false; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 4e490e3db2f8..fe755c1a0af9 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -209,6 +209,8 @@ static inline int task_has_dl_policy(struct task_struct *p) */ #define SCHED_FLAG_SUGOV 0x10000000 +#define SCHED_DL_FLAGS (SCHED_FLAG_RECLAIM | SCHED_FLAG_DL_OVERRUN | SCHED_FLAG_SUGOV) + static inline bool dl_entity_is_special(struct sched_dl_entity *dl_se) { #ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL -- 2.30.2