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authorIngo Molnar <mingo@elte.hu>2006-12-13 00:34:40 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-13 09:05:50 -0800
commit81fc685a898f84d0787eeebb1c118de0bd3484a0 (patch)
treef604565b228c12b3db6037673870882c8022c4a9
parenta664089741aa9010333ecbdadbf5d9de62bafa2d (diff)
[PATCH] lockdep: improve verbose messages
Make verbose lockdep messages (off by default) more informative by printing out the hash chain key. (this patch was what helped me catch the earlier lockdep hash-collision bug) Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--kernel/lockdep.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 5d69c7d7407..5ba2825bd46 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -1264,7 +1264,7 @@ out_unlock_set:
* add it and return 0 - in this case the new dependency chain is
* validated. If the key is already hashed, return 1.
*/
-static inline int lookup_chain_cache(u64 chain_key)
+static inline int lookup_chain_cache(u64 chain_key, struct lock_class *class)
{
struct list_head *hash_head = chainhashentry(chain_key);
struct lock_chain *chain;
@@ -1286,9 +1286,13 @@ cache_hit:
__raw_spin_lock(&hash_lock);
return 1;
#endif
+ if (very_verbose(class))
+ printk("\nhash chain already cached, key: %016Lx tail class: [%p] %s\n", chain_key, class->key, class->name);
return 0;
}
}
+ if (very_verbose(class))
+ printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", chain_key, class->key, class->name);
/*
* Allocate a new chain entry from the static array, and add
* it to the hash:
@@ -2139,7 +2143,7 @@ out_calc_hash:
* (If lookup_chain_cache() returns with 1 it acquires
* hash_lock for us)
*/
- if (!trylock && (check == 2) && lookup_chain_cache(chain_key)) {
+ if (!trylock && (check == 2) && lookup_chain_cache(chain_key, class)) {
/*
* Check whether last held lock:
*