From bb065afb8ebd07a03155502dba29ebf0f6fe67e8 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 12 May 2008 21:21:00 +0200 Subject: [PATCH] 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 Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/lockdep.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 90a440cbd6d..65548eff029 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -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; }