From ce36f2f3eb6613a73bc6f3a5256bde7dd3f95710 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Sun, 28 Sep 2014 23:44:21 +0200 Subject: [PATCH] rcu: More info about potential deadlocks with rcu_read_unlock() The comment above rcu_read_unlock() explains the potential deadlock if the caller holds one of the locks taken by rt_mutex_unlock() paths, but it is not clear from this documentation that any lock which can be taken from interrupt can lead to deadlock as well and we need to take rt_mutex_lock() into account too. The problem is that rt_mutex_lock() takes wait_lock without disabling irqs, and thus an interrupt taking some LOCK can obviously race with rcu_read_unlock_special() called with the same LOCK held. Signed-off-by: Oleg Nesterov Signed-off-by: Paul E. McKenney --- Reading git-format-patch failed