From: Chengming Zhou <zhouchengming@bytedance.com>
To: linux-kernel@vger.kernel.org, pmladek@suse.com,
sergey.senozhatsky@gmail.com, rostedt@goodmis.org,
mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
bsegall@google.com, mgorman@suse.de
Cc: zhouchengming@bytedance.com, songmuchun@bytedance.com
Subject: [PATCH 2/2] sched: mark PRINTK_DEFERRED_CONTEXT_MASK in __schedule()
Date: Mon, 28 Sep 2020 00:11:30 +0800 [thread overview]
Message-ID: <20200927161130.33172-2-zhouchengming@bytedance.com> (raw)
In-Reply-To: <20200927161130.33172-1-zhouchengming@bytedance.com>
The WARN_ON/WARN_ON_ONCE with rq lock held in __schedule() should be
deferred by marking the PRINTK_DEFERRED_CONTEXT_MASK, or will cause
deadlock on rq lock in the printk path.
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
kernel/sched/core.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 2d95dc3f4644..81d8bf614225 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4444,6 +4444,7 @@ static void __sched notrace __schedule(bool preempt)
*/
rq_lock(rq, &rf);
smp_mb__after_spinlock();
+ printk_deferred_enter();
/* Promote REQ to ACT */
rq->clock_update_flags <<= 1;
@@ -4530,6 +4531,7 @@ static void __sched notrace __schedule(bool preempt)
rq_unlock_irq(rq, &rf);
}
+ printk_deferred_exit();
balance_callback(rq);
}
--
2.11.0
next prev parent reply other threads:[~2020-09-27 16:11 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-27 16:11 [PATCH 1/2] printk: Add printk_deferred_{enter, exit} Chengming Zhou
2020-09-27 16:11 ` Chengming Zhou [this message]
2020-09-28 7:32 ` [PATCH 2/2] sched: mark PRINTK_DEFERRED_CONTEXT_MASK in __schedule() Peter Zijlstra
2020-09-28 7:52 ` Joe Perches
2020-09-28 8:00 ` Peter Zijlstra
2020-09-28 8:06 ` Peter Zijlstra
2020-09-28 8:54 ` [External] " Chengming Zhou
2020-09-28 9:01 ` Peter Zijlstra
2020-09-28 10:04 ` Chengming Zhou
2020-09-28 10:25 ` Peter Zijlstra
2020-09-28 23:50 ` Sergey Senozhatsky
2020-09-29 14:27 ` Petr Mladek
2020-09-29 15:09 ` Peter Zijlstra
2020-09-30 0:48 ` Sergey Senozhatsky
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