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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 5417DC4338F for ; Tue, 27 Jul 2021 10:11:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2827C61042 for ; Tue, 27 Jul 2021 10:11:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236219AbhG0KLM (ORCPT ); Tue, 27 Jul 2021 06:11:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45028 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236229AbhG0KLK (ORCPT ); Tue, 27 Jul 2021 06:11:10 -0400 Received: from mail-wr1-x44a.google.com (mail-wr1-x44a.google.com [IPv6:2a00:1450:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A0BEC061764 for ; Tue, 27 Jul 2021 03:11:10 -0700 (PDT) Received: by mail-wr1-x44a.google.com with SMTP id s8-20020a5d42480000b02901404c442853so5815259wrr.12 for ; Tue, 27 Jul 2021 03:11:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=M8fGV9XuOvxhABWv6H1Hi3CTxbO7iUQ4hHxLrwKgnhI=; b=qQ8Lgx5tLTtB2PtilQSqTMr3gP5bLAJtlapPDv58e5/sXsVab1XL10t4XYS627C0cZ Nuc7Lieiisf1BMqWF4k6bY8gfoSRs7OkiOfqmBq9vq39UlEe/42670Lo98FZYJ+6H2T1 rsu+Hus+4JjHP5/bwtTyZGE5F70x2FbUmpAlvr9JR5ViUjLjXau0SZrc0ItjWJz2NcBU fT2ZztTv4ZLA9EPeXdQZw9gLghJ68SJ0UmBegrsXoggKM0KBRsoOcO7ehGJpdYmD8HhA t8+T3cfDJ00/dp7Y3Pnb83EKXicKZVprgX5PMJQrzmMWn4VjIftMjK3pv4GryF+DY4TG OTXQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=M8fGV9XuOvxhABWv6H1Hi3CTxbO7iUQ4hHxLrwKgnhI=; b=BJdPvgPGY3ftpwV+t8qG3Wn1ay8qLNXsJmSu1fbZTN3xZ4ueQSnjPx6lR3ODtSZC+z ieZvhhFbaBlXwtLd8sALZVf3nSScSDG9lirgpS8ZwCOo6IMWdJ6+bUGqROrw9iSVAZrv 5vFS+Weeif9MajquhbYcUOEtfw75fSnedNFInGyFSvLw6skf+iUBthx6MdN7fgKqp/pu KpyTd0rBsjYzyJyUNhO8PpyQoEdI8hRoaYduiXuwAjtcSO1XFWkkd0Qm7DIyMNeBM1F2 0eeAAM1IItCLHJ7IT5n7OMwcTdsRbf5XhDpkwTl7hqy6d7YUe6bjniEesU6NhQECJZxg 8HNw== X-Gm-Message-State: AOAM532iiJHAeTpiM8GTLAXcbh85mPIvcxxisw/lRzzp48OqX3ILd3Ce hXv8a+xRsYGrC5ny74fjm7qcqPI1Gnb1 X-Google-Smtp-Source: ABdhPJzXcB/fubpj/sGnBdXnymKNQrFX3qziewZPyRKhJDQjyGjZNPrKvHhgRd6gheTvat7hr+AYNybTrS/K X-Received: from luke.lon.corp.google.com ([2a00:79e0:d:210:c468:e033:fa2b:3a6]) (user=qperret job=sendgmr) by 2002:a7b:c8d2:: with SMTP id f18mr21166013wml.135.1627380669011; Tue, 27 Jul 2021 03:11:09 -0700 (PDT) Date: Tue, 27 Jul 2021 11:11:01 +0100 In-Reply-To: <20210727101103.2729607-1-qperret@google.com> Message-Id: <20210727101103.2729607-2-qperret@google.com> Mime-Version: 1.0 References: <20210727101103.2729607-1-qperret@google.com> X-Mailer: git-send-email 2.32.0.432.gabb21c7263-goog Subject: [PATCH 1/2] sched/deadline: Fix reset_on_fork reporting of DL tasks From: Quentin Perret To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , linux-kernel@vger.kernel.org Cc: Quentin Perret Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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 aaacd6cfd42f..5cafc642e647 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2741,7 +2741,7 @@ 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); } @@ -2754,7 +2754,8 @@ 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; } /* @@ -2851,7 +2852,7 @@ 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 14a41a243f7b..ad3aee63db26 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -227,6 +227,8 @@ static inline void update_avg(u64 *avg, u64 sample) */ #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 -- 2.32.0.432.gabb21c7263-goog