diff options
| author | Steven Rostedt <rostedt@goodmis.org> | 2014-04-30 00:13:08 (GMT) |
|---|---|---|
| committer | Scott Wood <scottwood@freescale.com> | 2015-02-13 22:21:15 (GMT) |
| commit | 8fca2ff3a8f5da52d4741e398f90b553eb74617e (patch) | |
| tree | aa1d009b845c7b221b2c5a11b44c4e70a7ad06ad /kernel | |
| parent | 5891b646b27275d6862ef026e4daa0a15f307e25 (diff) | |
| download | linux-fsl-qoriq-8fca2ff3a8f5da52d4741e398f90b553eb74617e.tar.xz | |
rt: Move migrate_disable up in trylocks
The changes to move the migrate_disable() down in the trylocks()
caused race conditions to appear in the cpu hotplug code. The
migrate disables must be done before any of the rtmutexes are
taken, otherwise a lock may be held that prevents hotplug from
moving forward.
Link: http://lkml.kernel.org/r/20140429201308.63292691@gandalf.local.home
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Nicholas Mc Guire <der.herr@hofr.at>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Kacur <jkacur@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/rt.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/kernel/rt.c b/kernel/rt.c index 5d17727..5f44def 100644 --- a/kernel/rt.c +++ b/kernel/rt.c @@ -180,12 +180,15 @@ EXPORT_SYMBOL(_mutex_unlock); */ int __lockfunc rt_write_trylock(rwlock_t *rwlock) { - int ret = rt_mutex_trylock(&rwlock->lock); + int ret; + + migrate_disable(); + ret = rt_mutex_trylock(&rwlock->lock); - if (ret) { + if (ret) rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_); - migrate_disable(); - } + else + migrate_enable(); return ret; } @@ -212,11 +215,12 @@ int __lockfunc rt_read_trylock(rwlock_t *rwlock) * write locked. */ if (rt_mutex_owner(lock) != current) { + migrate_disable(); ret = rt_mutex_trylock(lock); - if (ret) { + if (ret) rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_); - migrate_disable(); - } + else + migrate_enable(); } else if (!rwlock->read_depth) { ret = 0; } @@ -245,8 +249,8 @@ void __lockfunc rt_read_lock(rwlock_t *rwlock) */ if (rt_mutex_owner(lock) != current) { rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_); - __rt_spin_lock(lock); migrate_disable(); + __rt_spin_lock(lock); } rwlock->read_depth++; } |