From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Fri, 27 Feb 2015 16:57:09 +0000 (+0100)
Subject: locking/rtmutex: Set state back to running on error
X-Git-Tag: MMI-PSA29.97-13-9~10530^2
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=9d3e2d02f54160725d97f4ab1e1e8de493fbf33a;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git

locking/rtmutex: Set state back to running on error

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>
Acked-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: afffc6c1805d ("locking/rtmutex: Optimize setting task running after being blocked")
Link: http://lkml.kernel.org/r/1425056229-22326-4-git-send-email-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index e16e5542bf13..6357265a31ad 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1193,6 +1193,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 		ret = __rt_mutex_slowlock(lock, state, timeout, &waiter);
 
 	if (unlikely(ret)) {
+		__set_current_state(TASK_RUNNING);
 		if (rt_mutex_has_waiters(lock))
 			remove_waiter(lock, &waiter);
 		rt_mutex_handle_deadlock(ret, chwalk, &waiter);