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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Maarten Lankhorst <maarten.lankhorst@canonical.com>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: [PATCH 3/3] locking: rtmutex: set state back to running on error
Date: Fri, 27 Feb 2015 17:57:09 +0100
Message-ID: <1425056229-22326-4-git-send-email-bigeasy@linutronix.de> (raw)
In-Reply-To: <1425056229-22326-1-git-send-email-bigeasy@linutronix.de>

The "usual" path is:
- rt_mutex_slowlock()
 - set_current_state()
 - task_blocks_on_rt_mutex() (ret 0)
 - __rt_mutex_slowlock()
   - sleep or not but do return with __set_current_state(TASK_RUNNING)
 - back to caller.

In the early error case where task_blocks_on_rt_mutex() return -EDEADLK
we never change the task's state back to RUNNING. I assume this is
intended. Without this change after ww_mutex using rt_mutex the selftest
passes but later I get plenty of
| bad: scheduling from the idle thread!
backtraces.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 kernel/locking/rtmutex.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 6d7d72ffa619..c4d07f254bb4 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1305,6 +1305,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 	}
 
 	if (unlikely(ret)) {
+		set_current_state(TASK_RUNNING);
 		if (rt_mutex_has_waiters(lock))
 			remove_waiter(lock, &waiter);
 		/* ww_mutex need the error reported */
-- 
2.1.4


  parent reply index

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-27 16:57 rt_mutex based ww_mutex implementation Sebastian Andrzej Siewior
2015-02-27 16:57 ` [PATCH 1/3] locking: ww_mutex: add one level of indirection for access of the lock Sebastian Andrzej Siewior
2015-02-27 18:20   ` Maarten Lankhorst
2015-02-27 18:57     ` Sebastian Andrzej Siewior
2015-02-27 16:57 ` [PATCH 2/3] locking: ww_mutex: Allow to use rt_mutex instead of mutex for the baselock Sebastian Andrzej Siewior
2015-03-02  3:20   ` Mike Galbraith
2015-03-02  8:46     ` Maarten Lankhorst
2015-03-02 12:50       ` Mike Galbraith
2015-03-06 12:14       ` Sebastian Andrzej Siewior
2015-03-06 12:16         ` Maarten Lankhorst
2015-03-06 12:36           ` Sebastian Andrzej Siewior
2015-03-06 17:50             ` Mike Galbraith
2015-03-09 10:00               ` Sebastian Andrzej Siewior
2015-03-09 10:51                 ` Mike Galbraith
2015-03-09 11:07                   ` Sebastian Andrzej Siewior
2015-03-09 11:29                     ` Mike Galbraith
2015-03-09 13:21                       ` Sebastian Andrzej Siewior
2015-03-09 22:27                         ` Paul E. McKenney
2015-03-10 12:30   ` Peter Zijlstra
2015-03-10 12:37   ` Peter Zijlstra
2015-03-10 12:39     ` Peter Zijlstra
2015-03-10 14:10     ` Maarten Lankhorst
2015-03-10 15:28       ` Peter Zijlstra
2015-03-10 18:21         ` Maarten Lankhorst
2015-03-10 12:43   ` Peter Zijlstra
2015-03-10 12:46   ` Peter Zijlstra
2015-02-27 16:57 ` Sebastian Andrzej Siewior [this message]
2015-02-28 10:00   ` [tip:locking/urgent] locking/rtmutex: Set state back to running on error tip-bot for Sebastian Andrzej Siewior
2015-03-01  5:35   ` [PATCH 3/3] locking: rtmutex: set " Mike Galbraith
2015-03-01  8:48   ` [tip:locking/urgent] locking/rtmutex: Set " tip-bot for Sebastian Andrzej Siewior

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