Commit bb065afb authored May 12, 2008 by Steven Rostedt Committed by Thomas Gleixner May 23, 2008

lockdep: update lockdep_recursion on graph_lock



With the introduction of ftrace, it is possible to recurse into
the lockdep functions via the mcount call. To prevent possible
lockups, updating the lockdep_recursion counter on grabbing the internal
lockdep_lock should prevent deadlocks.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent a98a3c3f

kernel/lockdep.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -82,6 +82,8 @@ static int graph_lock(void)
		__raw_spin_unlock(&lockdep_lock);
		return 0;
		}
		/* prevent any recursions within lockdep from causing deadlocks */
		current->lockdep_recursion++;
		return 1;
		}

		@@ -90,6 +92,7 @@ static inline int graph_unlock(void)
		if (debug_locks && !__raw_spin_is_locked(&lockdep_lock))
		return DEBUG_LOCKS_WARN_ON(1);

		current->lockdep_recursion--;
		__raw_spin_unlock(&lockdep_lock);
		return 0;
		}