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Mon, 09 Nov 2026 08:37:00 -0800 (PST) Received: from victus-lab ([193.205.81.5]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4b96cd012e1sm138851295e9.8.2026.11.09.08.36.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Nov 2026 08:36:59 -0800 (PST) From: Yuri Andriaccio To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Tejun Heo , Johannes Weiner , =?UTF-8?q?Michal=20Koutn=C3=BD?= Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Luca Abeni , Yuri Andriaccio Subject: [RFC PATCH v7 24/29] sched/syscalls: Allow unpriviledged tasks to set RT priority inside cgroups. Date: Mon, 9 Nov 2026 17:36:10 +0100 Message-ID: <20261109163616.195264-25-yurand2000@gmail.com> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261109163616.195264-1-yurand2000@gmail.com> References: <20261109163616.195264-1-yurand2000@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Signed-off-by: Yuri Andriaccio --- kernel/sched/syscalls.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/kernel/sched/syscalls.c b/kernel/sched/syscalls.c index f1e9de478e1d..36bb07b10d41 100644 --- a/kernel/sched/syscalls.c +++ b/kernel/sched/syscalls.c @@ -444,15 +444,27 @@ static int user_check_sched_setscheduler(struct task_struct *p, if (rt_policy(policy)) { unsigned long rlim_rtprio = task_rlimit(p, RLIMIT_RTPRIO); + struct task_group *active_context; - /* Can't set/change the rt policy: */ - if (policy != p->policy && !rlim_rtprio) - goto req_priv; + if (!rt_group_sched_enabled()) + goto root_cgroup_checks; - /* Can't increase priority: */ - if (attr->sched_priority > p->rt_priority && - attr->sched_priority > rlim_rtprio) - goto req_priv; + scoped_guard(raw_spinlock_irq, dl_bw_lock_of_tg(p->sched_task_group)) { + active_context = dl_bandwidth_read(p->sched_task_group)->active_context; + } + + /* Allow changing to the rt policy when not in the root cgroup */ + if (active_context == &root_task_group) { +root_cgroup_checks: + /* Can't set/change the rt policy: */ + if (policy != p->policy && !rlim_rtprio) + goto req_priv; + + /* Can't increase priority: */ + if (attr->sched_priority > p->rt_priority && + attr->sched_priority > rlim_rtprio) + goto req_priv; + } } /* -- 2.56.0