From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Mon, 11 Aug 2008 10:34:42 +0000 (+0200)
Subject: lockdep: fix overflow in the hlock shrinkage code
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=b42e737e576339c795d9ac77a1fce6057f6bc0cf;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

lockdep: fix overflow in the hlock shrinkage code

There is a overflow by 1 case in the new shrunken hlock code.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 67f42b300c65..c88aa3d8e87f 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -191,7 +191,12 @@ struct lock_chain {
 };
 
 #define MAX_LOCKDEP_KEYS_BITS		11
-#define MAX_LOCKDEP_KEYS		(1UL << MAX_LOCKDEP_KEYS_BITS)
+/*
+ * Subtract one because we offset hlock->class_idx by 1 in order
+ * to make 0 mean no class. This avoids overflowing the class_idx
+ * bitfield and hitting the BUG in hlock_class().
+ */
+#define MAX_LOCKDEP_KEYS		((1UL << MAX_LOCKDEP_KEYS_BITS) - 1)
 
 struct held_lock {
 	/*