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From: Peter Zijlstra <peterz@infradead.org>
To: tglx@linutronix.de, mingo@kernel.org
Cc: linux-kernel@vger.kernel.org, bigeasy@linutronix.de,
	qais.yousef@arm.com, swood@redhat.com, peterz@infradead.org,
	valentin.schneider@arm.com, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	bristot@redhat.com, vincent.donnefort@arm.com, tj@kernel.org,
	ouwen210@hotmail.com
Subject: [PATCH v4 18/19] sched: Deny self-issued __set_cpus_allowed_ptr() when migrate_disable()
Date: Fri, 23 Oct 2020 12:12:16 +0200	[thread overview]
Message-ID: <20201023102347.786713233@infradead.org> (raw)
In-Reply-To: 20201023101158.088940906@infradead.org

From: Valentin Schneider <valentin.schneider@arm.com>

  migrate_disable();
  set_cpus_allowed_ptr(current, {something excluding task_cpu(current)});
  affine_move_task(); <-- never returns

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201013140116.26651-1-valentin.schneider@arm.com
---
 kernel/sched/core.c |   13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2182,8 +2182,17 @@ static int __set_cpus_allowed_ptr(struct
 		goto out;
 	}
 
-	if (!(flags & SCA_MIGRATE_ENABLE) && cpumask_equal(&p->cpus_mask, new_mask))
-		goto out;
+	if (!(flags & SCA_MIGRATE_ENABLE)) {
+		if (cpumask_equal(&p->cpus_mask, new_mask))
+			goto out;
+
+		if (WARN_ON_ONCE(p == current &&
+				 is_migration_disabled(p) &&
+				 !cpumask_test_cpu(task_cpu(p), new_mask))) {
+			ret = -EBUSY;
+			goto out;
+		}
+	}
 
 	/*
 	 * Picking a ~random cpu helps in cases where we are changing affinity



  parent reply	other threads:[~2020-10-23 10:25 UTC|newest]

Thread overview: 81+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-23 10:11 [PATCH v4 00/19] sched: Migrate disable support Peter Zijlstra
2020-10-23 10:11 ` [PATCH v4 01/19] stop_machine: Add function and caller debug info Peter Zijlstra
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2020-10-23 10:12 ` [PATCH v4 02/19] sched: Fix balance_callback() Peter Zijlstra
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2020-11-11 20:30     ` Paul Bolle
2020-11-11 20:45       ` Peter Zijlstra
2020-10-23 10:12 ` [PATCH v4 03/19] sched/hotplug: Ensure only per-cpu kthreads run during hotplug Peter Zijlstra
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2020-10-23 10:12 ` [PATCH v4 04/19] sched/core: Wait for tasks being pushed away on hotplug Peter Zijlstra
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2020-10-23 10:12 ` [PATCH v4 05/19] workqueue: Manually break affinity " Peter Zijlstra
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2020-10-23 10:12 ` [PATCH v4 06/19] sched/hotplug: Consolidate task migration on CPU unplug Peter Zijlstra
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2020-10-23 10:12 ` [PATCH v4 07/19] sched: Fix hotplug vs CPU bandwidth control Peter Zijlstra
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2020-10-23 10:12 ` [PATCH v4 08/19] sched: Massage set_cpus_allowed() Peter Zijlstra
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2020-10-23 10:12 ` [PATCH v4 09/19] sched: Add migrate_disable() Peter Zijlstra
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2020-10-23 10:12 ` [PATCH v4 10/19] sched: Fix migrate_disable() vs set_cpus_allowed_ptr() Peter Zijlstra
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2020-11-12 16:38   ` [PATCH v4 10/19] " Qian Cai
2020-11-12 17:26     ` Valentin Schneider
2020-11-12 18:01       ` Qian Cai
2020-11-12 19:31         ` Valentin Schneider
2020-11-12 19:41           ` Qian Cai
2020-11-12 20:37           ` Qian Cai
2020-11-12 21:26             ` Valentin Schneider
2020-11-13 10:27           ` Peter Zijlstra
2020-11-12 18:35       ` Qian Cai
2020-11-20 12:34     ` [tip: sched/core] sched/core: Add missing completion for affine_move_task() waiters tip-bot2 for Valentin Schneider
2020-10-23 10:12 ` [PATCH v4 11/19] sched/core: Make migrate disable and CPU hotplug cooperative Peter Zijlstra
2020-10-29 16:27   ` Valentin Schneider
2020-10-29 17:34     ` Peter Zijlstra
2020-10-29 17:55       ` Valentin Schneider
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2020-11-13 15:06   ` [PATCH v4 11/19] " Qian Cai
2020-11-17 19:28     ` Valentin Schneider
2020-11-18 14:44       ` Qian Cai
2020-11-23 18:13         ` Sebastian Andrzej Siewior
2020-12-02 21:59           ` Qian Cai
2020-12-03 12:31           ` Qian Cai
2020-12-04  0:23       ` Qian Cai
2020-12-04 21:19       ` Qian Cai
2020-12-05 18:37         ` Valentin Schneider
2020-12-06  1:17           ` Qian Cai
2020-12-07 19:27         ` Valentin Schneider
2020-12-08 13:46           ` Qian Cai
2020-12-09 19:16             ` Valentin Schneider
2020-10-23 10:12 ` [PATCH v4 12/19] sched,rt: Use cpumask_any*_distribute() Peter Zijlstra
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2020-10-23 10:12 ` [PATCH v4 13/19] sched,rt: Use the full cpumask for balancing Peter Zijlstra
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2020-10-23 10:12 ` [PATCH v4 14/19] sched, lockdep: Annotate ->pi_lock recursion Peter Zijlstra
2020-10-29 16:27   ` Valentin Schneider
2020-10-29 17:38     ` Peter Zijlstra
2020-10-29 18:09       ` Valentin Schneider
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2020-10-23 10:12 ` [PATCH v4 15/19] sched: Fix migrate_disable() vs rt/dl balancing Peter Zijlstra
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2020-12-26 13:54   ` [PATCH v4 15/19] " Qais Yousef
2021-03-05 14:56     ` Peter Zijlstra
2021-03-05 15:41       ` Valentin Schneider
2021-03-05 17:11         ` Qais Yousef
2021-03-10 14:44         ` Qais Yousef
2021-03-05 16:48       ` Qais Yousef
2020-10-23 10:12 ` [PATCH v4 16/19] sched/proc: Print accurate cpumask vs migrate_disable() Peter Zijlstra
2020-11-11  8:23   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2020-10-23 10:12 ` [PATCH v4 17/19] sched: Add migrate_disable() tracepoints Peter Zijlstra
2020-10-29 16:27   ` Valentin Schneider
2020-10-29 17:43     ` Peter Zijlstra
2020-10-29 17:56       ` Valentin Schneider
2020-10-29 17:59         ` Peter Zijlstra
2020-10-23 10:12 ` Peter Zijlstra [this message]
2020-10-23 10:12 ` [PATCH v4 19/19] sched: Comment affine_move_task() Peter Zijlstra
2020-10-29 16:27   ` Valentin Schneider
2020-10-29 17:44     ` Peter Zijlstra
2020-10-29 19:03 ` [PATCH v4 00/19] sched: Migrate disable support Valentin Schneider
2020-11-09 16:39 ` Daniel Bristot de Oliveira

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