Thomas Gleixner 0782e63bc6 sched: Handle priority boosted tasks proper in setscheduler() ...

Ronny reported that the following scenario is not handled correctly:

	T1 (prio = 10)
	   lock(rtmutex);

	T2 (prio = 20)
	   lock(rtmutex)
	      boost T1

	T1 (prio = 20)
	   sys_set_scheduler(prio = 30)
	   T1 prio = 30
	   ....
	   sys_set_scheduler(prio = 10)
	   T1 prio = 30

The last step is wrong as T1 should now be back at prio 20.

Commit c365c292d0 ("sched: Consider pi boosting in setscheduler()")
only handles the case where a boosted tasks tries to lower its
priority.

Fix it by taking the new effective priority into account for the
decision whether a change of the priority is required.

Reported-by: Ronny Meeus <[email protected]>
Tested-by: Steven Rostedt <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Steven Rostedt <[email protected]>
Cc: <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Mike Galbraith <[email protected]>
Fixes: c365c292d0 ("sched: Consider pi boosting in setscheduler()")
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1505051806060.4225@nanos
Signed-off-by: Ingo Molnar <[email protected]>

2015-05-08 11:53:55 +02:00

..

lglock.c

locking: Move the lglocks code to kernel/locking/

2013-11-06 09:24:20 +01:00

lockdep_internals.h

lockdep: Increase static allocations

2014-04-18 14:20:50 +02:00

lockdep_proc.c

lockdep/proc: Fix lock-time avg computation

2013-11-11 12:41:34 +01:00

lockdep_states.h

…

lockdep.c

lockdep: Make print_lock() robust against concurrent release

2015-04-17 09:42:14 +02:00

locktorture.c

locktorture: Cleanup header usage

2014-09-30 00:10:02 -07:00

Makefile

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2015-02-11 17:42:32 -08:00

mcs_spinlock.h

locking: Remove ACCESS_ONCE() usage

2015-02-24 08:44:16 +01:00

mutex-debug.c

mutex: Always clear owner field upon mutex_unlock()

2015-01-09 11:20:39 +01:00

mutex-debug.h

…

mutex.c

locking/mutex: Further simplify mutex_spin_on_owner()

2015-04-09 08:10:23 +02:00

mutex.h

locking/mutexes: Use MUTEX_SPIN_ON_OWNER when appropriate

2014-08-13 10:32:02 +02:00

osq_lock.c

locking: Remove ACCESS_ONCE() usage

2015-02-24 08:44:16 +01:00

percpu-rwsem.c

locking: Move the percpu-rwsem code to kernel/locking/

2013-11-06 09:24:22 +01:00

qrwlock.c

arch, locking: Ciao arch_mutex_cpu_relax()

2014-07-17 12:32:47 +02:00

rtmutex_common.h

rtmutex: Cleanup deadlock detector debug logic

2014-06-21 22:05:30 +02:00

rtmutex-debug.c

rtmutex: Cleanup deadlock detector debug logic

2014-06-21 22:05:30 +02:00

rtmutex-debug.h

rtmutex: Cleanup deadlock detector debug logic

2014-06-21 22:05:30 +02:00

rtmutex-tester.c

locking: Move the rtmutex code to kernel/locking/

2013-11-06 09:23:59 +01:00

rtmutex.c

sched: Handle priority boosted tasks proper in setscheduler()

2015-05-08 11:53:55 +02:00

rtmutex.h

rtmutex: Cleanup deadlock detector debug logic

2014-06-21 22:05:30 +02:00

rwsem-spinlock.c

locking/rwsem: Document barrier need when waking tasks

2015-02-18 16:57:10 +01:00

rwsem-xadd.c

locking/rwsem: Fix lock optimistic spinning when owner is not running

2015-03-07 09:50:49 +01:00

rwsem.c

locking/rwsem: Set lock ownership ASAP

2015-02-18 16:57:13 +01:00

rwsem.h

locking/rwsem: Set lock ownership ASAP

2015-02-18 16:57:13 +01:00

semaphore.c

locking/semaphore: Resolve some shadow warnings

2014-09-04 07:17:24 +02:00

spinlock_debug.c

locking: Move the spinlock code to kernel/locking/

2013-11-06 07:55:21 +01:00

spinlock.c

spinlock: Add spin_lock_bh_nested()

2015-01-03 14:32:57 -05:00