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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2008-08-11 12:34:42 +0200
committerIngo Molnar <mingo@elte.hu>2008-08-11 12:34:42 +0200
commitb42e737e576339c795d9ac77a1fce6057f6bc0cf (patch)
tree05aa0ba4f7dfd8d8a5ac3dc85893c18a20f159d3 /include/linux/lockdep.h
parent3295f0ef9ff048a4619ede597ad9ec9cab725654 (diff)
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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>
Diffstat (limited to 'include/linux/lockdep.h')
-rw-r--r--include/linux/lockdep.h7
1 files changed, 6 insertions, 1 deletions
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 67f42b3..c88aa3d 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 {
/*
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