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| author | Gregory Haskins <ghaskins@novell.com> | 2007-10-11 22:11:11 +0200 |
|---|---|---|
| committer | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2007-10-11 22:11:11 +0200 |
| commit | 3aa416b07f0adf01c090baab26fb70c35ec17623 (patch) | |
| tree | a2c2c2f7bd8445b138b293ba6661833f970954ee /kernel/lockdep.c | |
| parent | 94c61c0aeffe64452e742087cf803d0347ef8418 (diff) | |
| download | lwn-3aa416b07f0adf01c090baab26fb70c35ec17623.tar.gz lwn-3aa416b07f0adf01c090baab26fb70c35ec17623.zip | |
lockdep: fix mismatched lockdep_depth/curr_chain_hash
It is possible for the current->curr_chain_key to become inconsistent with the
current index if the chain fails to validate. The end result is that future
lock_acquire() operations may inadvertently fail to find a hit in the cache
resulting in a new node being added to the graph for every acquire.
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/lockdep.c')
| -rw-r--r-- | kernel/lockdep.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 734da579ad13..42ae4a5ab4dc 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -1521,7 +1521,7 @@ cache_hit: } static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, - struct held_lock *hlock, int chain_head) + struct held_lock *hlock, int chain_head, u64 chain_key) { /* * Trylock needs to maintain the stack of held locks, but it @@ -1534,7 +1534,7 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, * graph_lock for us) */ if (!hlock->trylock && (hlock->check == 2) && - lookup_chain_cache(curr->curr_chain_key, hlock->class)) { + lookup_chain_cache(chain_key, hlock->class)) { /* * Check whether last held lock: * @@ -1576,7 +1576,7 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, #else static inline int validate_chain(struct task_struct *curr, struct lockdep_map *lock, struct held_lock *hlock, - int chain_head) + int chain_head, u64 chain_key) { return 1; } @@ -2450,11 +2450,11 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, chain_head = 1; } chain_key = iterate_chain_key(chain_key, id); - curr->curr_chain_key = chain_key; - if (!validate_chain(curr, lock, hlock, chain_head)) + if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) return 0; + curr->curr_chain_key = chain_key; curr->lockdep_depth++; check_chain_key(curr); #ifdef CONFIG_DEBUG_LOCKDEP |