rtmutex proxy locking complicates the logic a bit and opens up the possibility for a task to wake and attempt to take another sleeping lock without knowing it has been enqueued on another lock already. Add a BUG_ON to catch this scenario early. Signed-off-by: Darren Hart <dvhltc@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: Eric Dumazet <eric.dumazet@xxxxxxxxx> Cc: John Kacur <jkacur@xxxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Mike Galbraith <efault@xxxxxx> --- kernel/rtmutex.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index baac7d9..22f9d18 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -459,6 +459,9 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock, top_waiter = rt_mutex_top_waiter(lock); plist_add(&waiter->list_entry, &lock->wait_list); + /* Tasks can only block on one lock at a time. */ + BUG_ON(task->pi_blocked_on != NULL); + task->pi_blocked_on = waiter; raw_spin_unlock(&task->pi_lock); -- 1.7.0.4 -- 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
