From: Ingo Molnar Date: Wed, 13 Dec 2006 08:34:40 +0000 (-0800) Subject: [PATCH] lockdep: improve verbose messages X-Git-Tag: v2.6.20-rc1~90 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=81fc685a898f84d0787eeebb1c118de0bd3484a0;p=linux-2.6 [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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 5d69c7d740..5ba2825bd4 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: *