3.12.15-rt26-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Steven Rostedt <rostedt@xxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxx Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Mike Galbraith <umgwanakikbuti@xxxxxxxxx> Cc: Nicholas Mc Guire <der.herr@xxxxxxx> Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Cc: linux-rt-users <linux-rt-users@xxxxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: John Kacur <jkacur@xxxxxxxxxx> Cc: Clark Williams <williams@xxxxxxxxxx> --- kernel/rt.c | 20 ++++++++++++-------- 1 file 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++; } -- 1.8.5.3 -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
