From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Joe Korty <Joe.Korty@concurrent-rt.com>
Cc: "julia@ni.com" <julia@ni.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"oleg@redhat.com" <oleg@redhat.com>,
"linux-rt-users@vger.kernel.org" <linux-rt-users@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: [PATCH RT] rtmutex/rwlock: preserve state like a sleeping lock
Date: Fri, 11 Jan 2019 21:22:57 +0100 [thread overview]
Message-ID: <20190111202257.5wcqht6nwx7y6lmy@linutronix.de> (raw)
In-Reply-To: <20181119194619.GA32121@zipoli.concurrent-rt.com>
The rwlock is spinning while acquiring a lock. Therefore it must become
a sleeping lock on RT and preserve its task state while sleeping and
waiting for the lock.
Reported-by: Joe Korty <Joe.Korty@concurrent-rt.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/locking/rwlock-rt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/locking/rwlock-rt.c b/kernel/locking/rwlock-rt.c
index f2e155b2c4a8b..c3b91205161cc 100644
--- a/kernel/locking/rwlock-rt.c
+++ b/kernel/locking/rwlock-rt.c
@@ -128,7 +128,7 @@ void __sched __read_rt_lock(struct rt_rw_lock *lock)
* That would put Reader1 behind the writer waiting on
* Reader2 to call read_unlock() which might be unbound.
*/
- rt_mutex_init_waiter(&waiter, false);
+ rt_mutex_init_waiter(&waiter, true);
rt_spin_lock_slowlock_locked(m, &waiter, flags);
/*
* The slowlock() above is guaranteed to return with the rtmutex is
--
2.20.1
prev parent reply other threads:[~2019-01-11 20:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-19 19:46 [ptrace, rt] erratic behaviour in PTRACE_SINGLESET on 4.13-rt and later Joe Korty
2018-11-20 17:29 ` Steven Rostedt
2018-11-27 14:58 ` Clark Williams
2018-11-27 15:10 ` Joe Korty
2019-01-14 14:45 ` bigeasy
2019-01-11 20:22 ` Sebastian Andrzej Siewior [this message]
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