rcu: More info about potential deadlocks with rcu_read_unlock()

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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 <oleg@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

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Oleg Nesterov 2014-09-28 23:44:21 +02:00 • committed by Paul E. McKenney

parent b6331ae8af

commit ce36f2f3eb

1 changed files with 3 additions and 1 deletions

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include/linux/rcupdate.h

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