2019-01-14 10:08:29 +00:00
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Fri, 11 Jan 2019 21:16:31 +0100
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Subject: [PATCH] rtmutex/rwlock: preserve state like a sleeping lock
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2019-02-27 18:51:46 +00:00
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.25-rt16.tar.xz
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2019-01-14 10:08:29 +00:00
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The rwlock is spinning while acquiring a lock. Therefore it must become
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a sleeping lock on RT and preserve its task state while sleeping and
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waiting for the lock to become available.
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Reported-by: Joe Korty <Joe.Korty@concurrent-rt.com>
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Cc: stable-rt@vger.kernel.org
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/locking/rwlock-rt.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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--- a/kernel/locking/rwlock-rt.c
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+++ b/kernel/locking/rwlock-rt.c
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@@ -128,7 +128,7 @@ void __sched __read_rt_lock(struct rt_rw
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* That would put Reader1 behind the writer waiting on
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* Reader2 to call read_unlock() which might be unbound.
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*/
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- rt_mutex_init_waiter(&waiter, false);
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+ rt_mutex_init_waiter(&waiter, true);
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rt_spin_lock_slowlock_locked(m, &waiter, flags);
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/*
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* The slowlock() above is guaranteed to return with the rtmutex is
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