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From:   Vineeth Remanan Pillai <vpillai@digitalocean.com>
To:     Nishanth Aravamudan <naravamudan@digitalocean.com>,
        Julien Desfossez <jdesfossez@digitalocean.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Tim Chen <tim.c.chen@linux.intel.com>, mingo@kernel.org,
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        fweisbec@gmail.com, keescook@chromium.org, kerrnel@google.com,
        Phil Auld <pauld@redhat.com>, Aaron Lu <aaron.lwe@gmail.com>,
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        Mel Gorman <mgorman@techsingularity.net>,
        Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
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        Joel Fernandes <joelaf@google.com>, joel@joelfernandes.org,
        vineethrp@gmail.com, Chen Yu <yu.c.chen@intel.com>,
        Christian Brauner <christian.brauner@ubuntu.com>
Subject: [RFC PATCH 04/16] sched/fair: Add a few assertions
Date:   Tue, 30 Jun 2020 21:32:25 +0000
Message-Id: <8916c2d1121bb35ef0fe52fd050bf9705e673793.1593530334.git.vpillai@digitalocean.com>
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From: Peter Zijlstra <peterz@infradead.org>

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/sched/fair.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 5e9f11c8256f..e44a43b87975 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6203,6 +6203,11 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
 	}
 
 symmetric:
+	/*
+	 * per-cpu select_idle_mask usage
+	 */
+	lockdep_assert_irqs_disabled();
+
 	if (available_idle_cpu(target) || sched_idle_cpu(target))
 		return target;
 
@@ -6644,8 +6649,6 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)
  * certain conditions an idle sibling CPU if the domain has SD_WAKE_AFFINE set.
  *
  * Returns the target CPU number.
- *
- * preempt must be disabled.
  */
 static int
 select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_flags)
@@ -6656,6 +6659,11 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
 	int want_affine = 0;
 	int sync = (wake_flags & WF_SYNC) && !(current->flags & PF_EXITING);
 
+	/*
+	 * required for stable ->cpus_allowed
+	 */
+	lockdep_assert_held(&p->pi_lock);
+
 	if (sd_flag & SD_BALANCE_WAKE) {
 		record_wakee(p);
 
-- 
2.17.1