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| author | Gregory Haskins <ghaskins@novell.com> | 2007-10-31 11:44:05 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-11-02 08:44:16 -0700 |
| commit | 8aa78d8d9e98513a529f99f12cfd577531021f9b (patch) | |
| tree | 8c6c121f86c4c290e255c13113dd5e75f7efe338 | |
| parent | 02d29bbef2858caeac240a3d6291695717845c41 (diff) | |
| download | lwn-8aa78d8d9e98513a529f99f12cfd577531021f9b.tar.gz lwn-8aa78d8d9e98513a529f99f12cfd577531021f9b.zip | |
lockdep: fix mismatched lockdep_depth/curr_chain_hash
patch 3aa416b07f0adf01c090baab26fb70c35ec17623 in mainline.
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.
[ peterz: this might explain some of the lockdep is so _slow_ complaints. ]
[ mingo: this does not impact the correctness of validation, but may slow
down future operations significantly, if the chain gets very long. ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | kernel/lockdep.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 1a5ff2211d88..072cf2533251 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -2166,7 +2166,6 @@ out_calc_hash: } #endif chain_key = iterate_chain_key(chain_key, id); - curr->curr_chain_key = chain_key; /* * Trylock needs to maintain the stack of held locks, but it @@ -2215,6 +2214,7 @@ out_calc_hash: if (unlikely(!debug_locks)) return 0; + curr->curr_chain_key = chain_key; curr->lockdep_depth++; check_chain_key(curr); #ifdef CONFIG_DEBUG_LOCKDEP |