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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2008-08-11 12:34:42 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-08-11 12:34:42 +0200 |
| commit | b42e737e576339c795d9ac77a1fce6057f6bc0cf (patch) | |
| tree | 05aa0ba4f7dfd8d8a5ac3dc85893c18a20f159d3 /include/linux/lockdep.h | |
| parent | 3295f0ef9ff048a4619ede597ad9ec9cab725654 (diff) | |
| download | lwn-b42e737e576339c795d9ac77a1fce6057f6bc0cf.tar.gz lwn-b42e737e576339c795d9ac77a1fce6057f6bc0cf.zip | |
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.h | 7 |
1 files changed, 6 insertions, 1 deletions
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 { /* |