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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 074/242] sched: Reenable interrupts in do_sched_yield()
Date:   Mon, 28 Dec 2020 13:47:59 +0100
Message-Id: <20201228124908.329826479@linuxfoundation.org>
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From: Thomas Gleixner <tglx@linutronix.de>

[ Upstream commit 345a957fcc95630bf5535d7668a59ed983eb49a7 ]

do_sched_yield() invokes schedule() with interrupts disabled which is
not allowed. This goes back to the pre git era to commit a6efb709806c
("[PATCH] irqlock patch 2.5.27-H6") in the history tree.

Reenable interrupts and remove the misleading comment which "explains" it.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/87r1pt7y5c.fsf@nanos.tec.linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/sched/core.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index c5599174e7450..7cedada731c1b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4826,12 +4826,8 @@ SYSCALL_DEFINE0(sched_yield)
 	schedstat_inc(rq->yld_count);
 	current->sched_class->yield_task(rq);
 
-	/*
-	 * Since we are going to call schedule() anyway, there's
-	 * no need to preempt or enable interrupts:
-	 */
 	preempt_disable();
-	rq_unlock(rq, &rf);
+	rq_unlock_irq(rq, &rf);
 	sched_preempt_enable_no_resched();
 
 	schedule();
-- 
2.27.0