Re: [rhashtable] [ INFO: possible recursive locking detected ]

On Wed, Mar 11, 2015 at 11:41:56PM -0400, David Miller wrote:

From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Thu, 12 Mar 2015 14:37:45 +1100

quoted

rhashtable: Add annotation to nested lock
    
Commit aa34a6cb0478842452bac58edb50d3ef9e178c92 ("rhashtable:
Add arbitrary rehash function") killed the annotation on the
nested lock which leads to bitching from lockdep.
    
Reported-by: Fengguang Wu <redacted>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

This doesn't apply to net-next, the second hunk gives a reject.

Sorry, I based on this on top of the cleanup patches sent earlier.
Here is a rebase on net-next.  I will resend the cleanups later.

--8<--
rhashtable: Add annotation to nested lock
    
Commit aa34a6cb0478842452bac58edb50d3ef9e178c92 ("rhashtable:
Add arbitrary rehash function") killed the annotation on the
nested lock which leads to bitching from lockdep.
    
Reported-by: Fengguang Wu <redacted>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index b1c19c5..d7f3db5 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c

@@ -234,7 +234,7 @@ static int rhashtable_rehash_one(struct rhashtable *ht, unsigned old_hash)
 
 	new_bucket_lock = bucket_lock(new_tbl, new_hash);
 
-	spin_lock(new_bucket_lock);
+	spin_lock_nested(new_bucket_lock, RHT_LOCK_NESTED);
 	head = rht_dereference_bucket(new_tbl->buckets[new_hash],
 				      new_tbl, new_hash);
 

@@ -415,7 +415,7 @@ static bool __rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj,
 	tbl = rht_dereference_rcu(ht->future_tbl, ht);
 	if (tbl != old_tbl) {
 		hash = obj_raw_hashfn(ht, tbl, rht_obj(ht, obj));
-		spin_lock(bucket_lock(tbl, hash));
+		spin_lock_nested(bucket_lock(tbl, hash), RHT_LOCK_NESTED);
 	}
 
 	if (compare &&

-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt